From: Jarkko Hietaniemi <jhi@iki.fi>
Date: Thu, 21 Feb 2002 20:02:27 +0000 (+0000)
Subject: Upgrade to Math::BigInt 1.51.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=b3abae2aec672e5343915a64fe25c941cfd52764;p=p5sagit%2Fp5-mst-13.2.git

Upgrade to Math::BigInt 1.51.

p4raw-id: //depot/perl@14817
---

diff --git a/MANIFEST b/MANIFEST
index e5ff86f..7341699 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -1134,19 +1134,25 @@ lib/look.pl			A "look" equivalent
 lib/Math/BigFloat.pm		An arbitrary precision floating-point arithmetic package
 lib/Math/BigInt.pm		An arbitrary precision integer arithmetic package
 lib/Math/BigInt/Calc.pm		Pure Perl module to support Math::BigInt
-lib/Math/BigInt/t/bare_mbi.t	Test Math::BigInt::CareCalc
+lib/Math/BigInt/t/bare_mbi.t	Test MBI under Math::BigInt::BareCalc
+lib/Math/BigInt/t/bare_mbf.t	Test MBF under Math::BigInt::BareCalc
 lib/Math/BigInt/t/bigfltpm.inc	Shared tests for bigfltpm.t and sub_mbf.t
 lib/Math/BigInt/t/bigfltpm.t	See if BigFloat.pm works
 lib/Math/BigInt/t/bigintc.t	See if BigInt/Calc.pm works
 lib/Math/BigInt/t/bigintpm.inc	Shared tests for bigintpm.t and sub_mbi.t
 lib/Math/BigInt/t/bigintpm.t	See if BigInt.pm works
 lib/Math/BigInt/t/calling.t	Test calling conventions
+lib/Math/BigInt/t/config.t	Test Math::BigInt->config()
+lib/Math/BigInt/t/constant.t	Test Math::BigInt/BigFloat under :constant
+lib/Math/BigInt/t/inf_nan.t	Special tests for inf and NaN handling
 lib/Math/BigInt/t/mbimbf.inc	Actual BigInt/BigFloat accuracy, precicion and fallback, round_mode tests
 lib/Math/BigInt/t/mbimbf.t	BigInt/BigFloat accuracy, precicion and fallback, round_mode
 lib/Math/BigInt/t/require.t	Test if require Math::BigInt works
 lib/Math/BigInt/t/sub_mbf.t	Empty subclass test of BigFloat
 lib/Math/BigInt/t/sub_mbi.t	Empty subclass test of BigInt
 lib/Math/BigInt/t/sub_mif.t	Test A & P with subclasses using mbimbf.inc
+lib/Math/BigInt/t/upgrade.inc	Actual tests for upgrade.t
+lib/Math/BigInt/t/upgrade.t	Test if use Math::BigInt(); under upgrade works
 lib/Math/BigInt/t/use.t		Test if use Math::BigInt(); works
 lib/Math/Complex.pm		A Complex package
 lib/Math/Complex.t		See if Math::Complex works
diff --git a/lib/Math/BigFloat.pm b/lib/Math/BigFloat.pm
index 92e53b3..2b7faae 100644
--- a/lib/Math/BigFloat.pm
+++ b/lib/Math/BigFloat.pm
@@ -1,5 +1,3 @@
-#!/usr/bin/perl -w
-
 # The following hash values are internally used:
 #   _e: exponent (BigInt)
 #   _m: mantissa (absolute BigInt)
@@ -10,7 +8,7 @@
 
 package Math::BigFloat;
 
-$VERSION = '1.27';
+$VERSION = '1.28';
 require 5.005;
 use Exporter;
 use Math::BigInt qw/objectify/;
@@ -18,6 +16,7 @@ use Math::BigInt qw/objectify/;
 
 use strict;
 use vars qw/$AUTOLOAD $accuracy $precision $div_scale $round_mode $rnd_mode/;
+use vars qw/$upgrade $downgrade/;
 my $class = "Math::BigFloat";
 
 use overload
@@ -25,6 +24,7 @@ use overload
                       ref($_[0])->bcmp($_[1],$_[0]) : 
                       ref($_[0])->bcmp($_[0],$_[1])},
 'int'	=>	sub { $_[0]->as_number() },		# 'trunc' to bigint
+'log'	=>	sub { $_[0]->blog() },
 ;
 
 ##############################################################################
@@ -43,6 +43,9 @@ $accuracy   = undef;
 $precision  = undef;
 $div_scale  = 40;
 
+$upgrade = undef;
+$downgrade = undef;
+
 ##############################################################################
 # the old code had $rnd_mode, so we need to support it, too
 
@@ -62,7 +65,7 @@ BEGIN { tie $rnd_mode, 'Math::BigFloat'; }
   # valid method aliases for AUTOLOAD
   my %methods = map { $_ => 1 }  
    qw / fadd fsub fmul fdiv fround ffround fsqrt fmod fstr fsstr fpow fnorm
-        fint facmp fcmp fzero fnan finf finc fdec flog
+        fint facmp fcmp fzero fnan finf finc fdec flog ffac
 	fceil ffloor frsft flsft fone flog
       /;
   # valid method's that can be hand-ed up (for AUTOLOAD)
@@ -86,7 +89,7 @@ sub new
   # sign  => sign (+/-), or "NaN"
 
   my ($class,$wanted,@r) = @_;
- 
+
   # avoid numify-calls by not using || on $wanted!
   return $class->bzero() if !defined $wanted;	# default to 0
   return $wanted->copy() if UNIVERSAL::isa($wanted,'Math::BigFloat');
@@ -130,7 +133,7 @@ sub new
     $self->{_e} -= CORE::length($$mfv) if CORE::length($$mfv) != 0; 		
     $self->{sign} = $$mis;
     }
-  # print "mbf new ",join(' ',@r),"\n";
+  # print "mbf new $self->{sign} $self->{_m} e $self->{_e}\n";
   $self->bnorm()->round(@r);		# first normalize, then round
   }
 
@@ -337,7 +340,7 @@ sub bcmp
     return +1 if $x->{sign} eq '+inf';
     return -1 if $x->{sign} eq '-inf';
     return -1 if $y->{sign} eq '+inf';
-    return +1 if $y->{sign} eq '-inf';
+    return +1;
     }
 
   # check sign for speed first
@@ -356,9 +359,7 @@ sub bcmp
   my $lym = $y->{_m}->length();
   my $lx = $lxm + $x->{_e};
   my $ly = $lym + $y->{_e};
-  # print "x $x y $y lx $lx ly $ly\n";
-  my $l = $lx - $ly; $l = -$l if $x->{sign} eq '-';
-  # print "$l $x->{sign}\n";
+  my $l = $lx - $ly; $l->bneg() if $x->{sign} eq '-';
   return $l <=> 0 if $l != 0;
   
   # lengths (corrected by exponent) are equal
@@ -376,7 +377,7 @@ sub bcmp
     }
   my $rc = $xm->bcmp($ym);
   $rc = -$rc if $x->{sign} eq '-';		# -124 < -123
-  return $rc <=> 0;
+  $rc <=> 0;
   }
 
 sub bacmp 
@@ -392,7 +393,7 @@ sub bacmp
     return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
     return 0 if ($x->is_inf() && $y->is_inf());
     return 1 if ($x->is_inf() && !$y->is_inf());
-    return -1 if (!$x->is_inf() && $y->is_inf());
+    return -1;
     }
 
   # shortcut 
@@ -407,9 +408,7 @@ sub bacmp
   my $lym = $y->{_m}->length();
   my $lx = $lxm + $x->{_e};
   my $ly = $lym + $y->{_e};
-  # print "x $x y $y lx $lx ly $ly\n";
   my $l = $lx - $ly;
-  # print "$l $x->{sign}\n";
   return $l <=> 0 if $l != 0;
   
   # lengths (corrected by exponent) are equal
@@ -425,8 +424,7 @@ sub bacmp
     {
     $xm = $x->{_m}->copy()->blsft(-$diff,10);
     }
-  my $rc = $xm->bcmp($ym);
-  return $rc <=> 0;
+  $xm->bcmp($ym) <=> 0;
   }
 
 sub badd 
@@ -435,6 +433,7 @@ sub badd
   # return result as BFLOAT
   my ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
 
+  #print "mbf badd $x $y\n";
   # inf and NaN handling
   if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
     {
@@ -571,7 +570,7 @@ sub bdec
 
 sub blog
   {
-  my ($self,$x,$base,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(2,@_);
+  my ($self,$x,$base,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(2,@_);
 
   # http://www.efunda.com/math/taylor_series/logarithmic.cfm?search_string=log
 
@@ -579,38 +578,88 @@ sub blog
   #              _                               _
   # taylor:     |    u    1   u^3   1   u^5       |
   # ln (x)  = 2 |   --- + - * --- + - * --- + ... |  x > 0
-  #             |_   v    3    v    5   v        _|
+  #             |_   v    3   v^3   5   v^5      _|
 
-  return $x->bzero(@r) if $x->is_one();
-  return $x->bone(@r) if $x->bcmp($base) == 0;
+  # we need to limit the accuracy to protect against overflow
+  my $fallback = 0;
+  my $scale = 0;
+  my @params = $x->_find_round_parameters($a,$p,$r);
 
-  my $d = $r[0] || $self->accuracy() || 40;
-  $d += 2;					# 2 more for rounding
- 
-  my $u = $x->copy(); $u->bdec();
-  my $v = $x->copy(); $v->binc();
+  # no rounding at all, so must use fallback
+  if (scalar @params == 1)
+    {
+    # simulate old behaviour
+    $params[1] = $self->div_scale();	# and round to it as accuracy
+    $scale = $params[1]+4; 		# at least four more for proper round
+    $params[3] = $r;			# round mode by caller or undef
+    $fallback = 1;			# to clear a/p afterwards
+    }
+  else
+    {
+    # the 4 below is empirical, and there might be cases where it is not
+    # enough...
+    $scale = abs($params[1] || $params[2]) + 4;	# take whatever is defined
+    }
 
-  $x->bdec()->bdiv($v,$d); 			# first term: u/v
+  return $x->bzero(@params) if $x->is_one();
+  return $x->bnan() if $x->{sign} ne '+' || $x->is_zero();
+  #return $x->bone('+',@params) if $x->bcmp($base) == 0;
 
-  $u *= $u; $v *= $v;
-  my $below = $v->copy()->bmul($v);
-  my $over = $u->copy()->bmul($u);
+  # when user set globals, they would interfere with our calculation, so
+  # disable then and later re-enable them
+  no strict 'refs';
+  my $abr = "$self\::accuracy"; my $ab = $$abr; $$abr = undef;
+  my $pbr = "$self\::precision"; my $pb = $$pbr; $$pbr = undef;
+  # we also need to disable any set A or P on $x (_find_round_parameters took
+  # them already into account), since these would interfere, too
+  delete $x->{_a}; delete $x->{_p};
+  # need to disable $upgrade in BigInt, to aoid deep recursion
+  local $Math::BigInt::upgrade = undef;
+  
+  my $v = $x->copy(); $v->binc();		# v = x+1
+  $x->bdec(); my $u = $x->copy();		# u = x-1; x = x-1
+
+  $x->bdiv($v,$scale); 				# first term: u/v
+
+  my $below = $v->copy();
+  my $over = $u->copy();
+  $u *= $u; $v *= $v;				# u^2, v^2
+  $below->bmul($v);				# u^3, v^3
+  $over->bmul($u);
   my $factor = $self->new(3); my $two = $self->new(2);
 
   my $diff = $self->bone();
-  my $limit = $self->new("1E-". ($d-1)); my $last;
+  my $limit = $self->new("1E-". ($scale-1)); my $last;
   # print "diff $diff limit $limit\n";
-  while ($diff > $limit)
+  while ($diff->bcmp($limit) > 0)
     {
-    print "$x $over $below $factor\n";
+    #print "$x $over $below $factor\n";
     $diff = $x->copy()->bsub($last)->babs();
-    print "diff $diff $limit\n";
+    #print "diff $diff $limit\n";
     $last = $x->copy();
-    $x += $over->copy()->bdiv($below->copy()->bmul($factor),$d);
+    $x += $over->copy()->bdiv($below->copy()->bmul($factor),$scale);
     $over *= $u; $below *= $v; $factor->badd($two);
     }
   $x->bmul($two);
-  return $x->round(@r);
+  
+  # shortcut to not run trough _find_round_parameters again
+  if (defined $params[1])
+    {
+    $x->bround($params[1],$params[3]);		# then round accordingly
+    }
+  else
+    {
+    $x->bfround($params[2],$params[3]);		# then round accordingly
+    }
+  if ($fallback)
+    {
+    # clear a/p after round, since user did not request it
+    $x->{_a} = undef; $x->{_p} = undef;
+    }
+  # restore globals
+  $$abr = $ab; $$pbr = $pb;
+
+  $x;
   }
 
 sub blcm 
@@ -637,25 +686,37 @@ sub bgcd
   $x;
   }
 
+###############################################################################
+# is_foo methods (is_negative, is_positive are inherited from BigInt)
+
+sub is_int
+  {
+  # return true if arg (BFLOAT or num_str) is an integer
+  my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
+
+  return 1 if ($x->{sign} =~ /^[+-]$/) &&	# NaN and +-inf aren't
+    $x->{_e}->{sign} eq '+';			# 1e-1 => no integer
+  0;
+  }
+
 sub is_zero
   {
-  # return true if arg (BFLOAT or num_str) is zero (array '+', '0')
+  # return true if arg (BFLOAT or num_str) is zero
   my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
 
   return 1 if $x->{sign} eq '+' && $x->{_m}->is_zero();
-  return 0;
+  0;
   }
 
 sub is_one
   {
-  # return true if arg (BFLOAT or num_str) is +1 (array '+', '1')
-  # or -1 if signis given
+  # return true if arg (BFLOAT or num_str) is +1 or -1 if signis given
   my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
 
   my $sign = shift || ''; $sign = '+' if $sign ne '-';
   return 1
    if ($x->{sign} eq $sign && $x->{_e}->is_zero() && $x->{_m}->is_one()); 
-  return 0;
+  0;
   }
 
 sub is_odd
@@ -663,9 +724,9 @@ sub is_odd
   # return true if arg (BFLOAT or num_str) is odd or false if even
   my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
   
-  return 0 if $x->{sign} !~ /^[+-]$/;			# NaN & +-inf aren't
-  return 1 if ($x->{_e}->is_zero() && $x->{_m}->is_odd()); 
-  return 0;
+  return 1 if ($x->{sign} =~ /^[+-]$/) &&		# NaN & +-inf aren't
+    ($x->{_e}->is_zero() && $x->{_m}->is_odd()); 
+  0;
   }
 
 sub is_even
@@ -674,9 +735,10 @@ sub is_even
   my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
 
   return 0 if $x->{sign} !~ /^[+-]$/;			# NaN & +-inf aren't
-  return 1 if $x->{_m}->is_zero();			# 0e1 is even
-  return 1 if ($x->{_e}->is_zero() && $x->{_m}->is_even()); # 123.45 is never
-  return 0;
+#  return 1 if $x->{_m}->is_zero();			# 0e1 is even
+  return 1 if ($x->{_e}->{sign} eq '+' 			# 123.45 is never
+     && $x->{_m}->is_even()); 				# but 1200 is
+  0;
   }
 
 sub bmul 
@@ -757,6 +819,13 @@ sub bdiv
   $scale = $ly if $ly > $scale;
   my $diff = $ly - $lx;
   $scale += $diff if $diff > 0;		# if lx << ly, but not if ly << lx!
+    
+  # make copy of $x in case of list context for later reminder calculation
+  my $rem;
+  if (wantarray && !$y->is_one())
+    {
+    $rem = $x->copy();
+    }
 
   $x->{sign} = $x->{sign} ne $y->sign() ? '-' : '+'; 
 
@@ -792,11 +861,9 @@ sub bdiv
   
   if (wantarray)
     {
-    my $rem;
     if (!$y->is_one())
       {
-      $rem = $x->copy();
-      $rem->bmod($y,$params[1],$params[2],$params[3]);
+      $rem->bmod($y,$params[1],$params[2],$params[3]);	# copy already done
       }
     else
       {
@@ -852,7 +919,7 @@ sub bmod
     $x->blsft($shifty,10);		# 123 => 1230, $y->{_m} is already 25
     }
   # $ym is now mantissa of $y based on exponent 0
-  
+
   my $shiftx = 0;			# correct _e of $x by this
   if ($x->{_e}->{sign} eq '-')		# has digits after dot
     {
@@ -871,6 +938,8 @@ sub bmod
   $x->{_e}->bsub($shifty) if $shifty != 0;
   
   # now mantissas are equalized, exponent of $x is adjusted, so calc result
+#  $ym->{sign} = '-' if $neg; # bmod() will make the correction for us
+
   $x->{_m}->bmod($ym);
 
   $x->{sign} = '+' if $x->{_m}->is_zero();		# fix sign for -0
@@ -923,16 +992,19 @@ sub bsqrt
   # disable then and later re-enable them
   no strict 'refs';
   my $abr = "$self\::accuracy"; my $ab = $$abr; $$abr = undef;
-  $abr = "$self\::precision"; my $pb = $$abr; $$abr = undef;
+  my $pbr = "$self\::precision"; my $pb = $$pbr; $$pbr = undef;
   # we also need to disable any set A or P on $x (_find_round_parameters took
   # them already into account), since these would interfere, too
   delete $x->{_a}; delete $x->{_p};
+  # need to disable $upgrade in BigInt, to aoid deep recursion
+  local $Math::BigInt::upgrade = undef;
 
   my $xas = $x->as_number();
   my $gs = $xas->copy()->bsqrt();	# some guess
+
   if (($x->{_e}->{sign} ne '-')		# guess can't be accurate if there are
 					# digits after the dot
-   && ($xas->bcmp($gs * $gs) == 0))	# guess hit the nail on the head?
+   && ($xas->bacmp($gs * $gs) == 0))	# guess hit the nail on the head?
     {
     # exact result
     $x->{_m} = $gs; $x->{_e} = Math::BigInt->bzero(); $x->bnorm();
@@ -950,6 +1022,7 @@ sub bsqrt
       # clear a/p after round, since user did not request it
       $x->{_a} = undef; $x->{_p} = undef;
       }
+    ${"$self\::accuracy"} = $ab; ${"$self\::precision"} = $pb;
     return $x;
     }
   $gs = $self->new( $gs );		# BigInt to BigFloat
@@ -957,7 +1030,7 @@ sub bsqrt
   my $lx = $x->{_m}->length();
   $scale = $lx if $scale < $lx;
   my $e = $self->new("1E-$scale");	# make test variable
-  return $x->bnan() if $e->sign() eq 'NaN';
+#  return $x->bnan() if $e->sign() eq 'NaN';
 
   my $y = $x->copy();
   my $two = $self->new(2);
@@ -966,17 +1039,12 @@ sub bsqrt
   $y = $self->new($y) unless $y->isa('Math::BigFloat'); 
 
   my $rem;
-#  my $steps = 0;
   while ($diff >= $e)
     {
-#    return $x->bnan() if $gs->is_zero();
-
     $rem = $y->copy()->bdiv($gs,$scale)->badd($gs)->bdiv($two,$scale);
     $diff = $rem->copy()->bsub($gs)->babs();
     $gs = $rem->copy();
-#    $steps++;
     }
-#  print "steps $steps\n";
   # copy over to modify $x
   $x->{_m} = $rem->{_m}; $x->{_e} = $rem->{_e};
   
@@ -995,10 +1063,39 @@ sub bsqrt
     $x->{_a} = undef; $x->{_p} = undef;
     }
   # restore globals
-  ${"$self\::accuracy"} = $ab; ${"$self\::precision"} = $pb;
+  $$abr = $ab; $$pbr = $pb;
   $x;
   }
 
+sub bfac
+  {
+  # (BINT or num_str, BINT or num_str) return BINT
+  # compute factorial numbers
+  # modifies first argument
+  my ($self,$x,@r) = objectify(1,@_);
+
+  return $x->bnan() if $x->{sign} ne '+';	# inf, NnN, <0 etc => NaN
+  return $x->bone(@r) if $x->is_zero() || $x->is_one();		# 0 or 1 => 1
+
+  return $x->bnan() if $x->{_e}->{sign} ne '+';	# digits after dot?
+  
+  # use BigInt's bfac() for faster calc
+  $x->{_m}->blsft($x->{_e},10);		# un-norm m
+  $x->{_e}->bzero();			# norm $x again
+  $x->{_m}->bfac();			# factorial
+  $x->bnorm();
+ 
+  #my $n = $x->copy();
+  #$x->bone();
+  #my $f = $self->new(2);
+  #while ($f->bacmp($n) < 0)
+  #  {
+  #  $x->bmul($f); $f->binc();
+  #  }
+  #$x->bmul($f);					# last step
+  $x->round(@r);				# round
+  }
+
 sub bpow 
   {
   # (BFLOAT or num_str, BFLOAT or num_str) return BFLOAT
@@ -1093,7 +1190,7 @@ sub bfround
     return $x->bzero() if $scale < $zad;
     if ($scale == $zad)			# for 0.006, scale -3 and trunc
       {
-      $scale = -$len-1;
+      $scale = -$len;
       }
     else
       {
@@ -1114,29 +1211,31 @@ sub bfround
     {
     # 123 => 100 means length(123) = 3 - $scale (2) => 1
 
-    # calculate digits before dot
-    my $dbt = $x->{_m}->length(); $dbt += $x->{_e} if $x->{_e}->sign() eq '-';
-    # if not enough digits before dot, round to zero
-    return $x->bzero() if ($scale > $dbt) && ($dbt < 0);
-    # scale always >= 0 here
-    if ($dbt == 0)
-      {
-      # 0.49->bfround(1): scale == 1, dbt == 0: => 0.0
-      # 0.51->bfround(0): scale == 0, dbt == 0: => 1.0
-      # 0.5->bfround(0):  scale == 0, dbt == 0: => 0
-      # 0.05->bfround(0): scale == 0, dbt == 0: => 0
-      # print "$scale $dbt $x->{_m}\n";
-      $scale = -$x->{_m}->length();
-      }
-    elsif ($dbt > 0)
-      {
-      # correct by subtracting scale
-      $scale = $dbt - $scale;
-      }
+    my $dbt = $x->{_m}->length(); 
+    # digits before dot 
+    my $dbd = $dbt + $x->{_e}; 
+    # should be the same, so treat it as this 
+    $scale = 1 if $scale == 0; 
+    # shortcut if already integer 
+    return $x if $scale == 1 && $dbt <= $dbd; 
+    # maximum digits before dot 
+    ++$dbd;
+
+    if ($scale > $dbd) 
+       { 
+       # not enough digits before dot, so round to zero 
+       return $x->bzero; 
+       }
+    elsif ( $scale == $dbd )
+       { 
+       # maximum 
+       $scale = -$dbt; 
+       } 
     else
-      {
-      $scale = $x->{_m}->length() - $scale;
-      }
+       { 
+       $scale = $dbd - $scale; 
+       }
+
     }
   # print "using $scale for $x->{_m} with '$mode'\n";
   # pass sign to bround for rounding modes '+inf' and '-inf'
@@ -1257,12 +1356,11 @@ sub DESTROY
 
 sub AUTOLOAD
   {
-  # make fxxx and bxxx work
-  # my $self = $_[0];
+  # make fxxx and bxxx both work by selectively mapping fxxx() to MBF::bxxx()
+  # or falling back to MBI::bxxx()
   my $name = $AUTOLOAD;
 
   $name =~ s/.*:://;	# split package
-  #print "$name\n";
   no strict 'refs';
   if (!method_alias($name))
     {
@@ -1283,7 +1381,7 @@ sub AUTOLOAD
     return &{'Math::BigInt'."::$name"}(@_);
     }
   my $bname = $name; $bname =~ s/^f/b/;
-  *{$class."\:\:$name"} = \&$bname;
+  *{$class."::$name"} = \&$bname;
   &$bname;	# uses @_
   }
 
@@ -1337,20 +1435,28 @@ sub parts
 sub import
   {
   my $self = shift;
-  for ( my $i = 0; $i < @_ ; $i++ )
+  my $l = scalar @_; my $j = 0; my @a = @_;
+  for ( my $i = 0; $i < $l ; $i++, $j++)
     {
     if ( $_[$i] eq ':constant' )
       {
       # this rest causes overlord er load to step in
       # print "overload @_\n";
       overload::constant float => sub { $self->new(shift); }; 
-      splice @_, $i, 1; last;
+      splice @a, $j, 1; $j--;
+      }
+    elsif ($_[$i] eq 'upgrade')
+      {
+      # this causes upgrading
+      $upgrade = $_[$i+1];              # or undef to disable
+      my $s = 2; $s = 1 if @a-$j < 2;   # avoid "can not modify non-existant..."
+      splice @a, $j, $s; $j -= $s;
       }
     }
   # any non :constant stuff is handled by our parent, Exporter
   # even if @_ is empty, to give it a chance
-  $self->SUPER::import(@_);      	# for subclasses
-  $self->export_to_level(1,$self,@_);	# need this, too
+  $self->SUPER::import(@a);      	# for subclasses
+  $self->export_to_level(1,$self,@a);	# need this, too
   }
 
 sub bnorm
@@ -1434,30 +1540,41 @@ Math::BigFloat - Arbitrary size floating point math package
 
   use Math::BigFloat;
 
-  # Number creation	
-  $x = Math::BigInt->new($str);	# defaults to 0
-  $nan  = Math::BigInt->bnan(); # create a NotANumber
-  $zero = Math::BigInt->bzero();# create a "+0"
+  # Number creation
+  $x = Math::BigFloat->new($str);	# defaults to 0
+  $nan  = Math::BigFloat->bnan();	# create a NotANumber
+  $zero = Math::BigFloat->bzero();	# create a +0
+  $inf = Math::BigFloat->binf();	# create a +inf
+  $inf = Math::BigFloat->binf('-');	# create a -inf
+  $one = Math::BigFloat->bone();	# create a +1
+  $one = Math::BigFloat->bone('-');	# create a -1
 
   # Testing
-  $x->is_zero();		# return whether arg is zero or not
-  $x->is_nan();			# return whether arg is NaN or not
+  $x->is_zero();		# true if arg is +0
+  $x->is_nan();			# true if arg is NaN
   $x->is_one();			# true if arg is +1
   $x->is_one('-');		# true if arg is -1
   $x->is_odd();			# true if odd, false for even
   $x->is_even();		# true if even, false for odd
   $x->is_positive();		# true if >= 0
   $x->is_negative();		# true if <  0
-  $x->is_inf(sign)		# true if +inf or -inf (sign default '+')
+  $x->is_inf(sign);		# true if +inf, or -inf (default is '+')
+
   $x->bcmp($y);			# compare numbers (undef,<0,=0,>0)
   $x->bacmp($y);		# compare absolutely (undef,<0,=0,>0)
   $x->sign();			# return the sign, either +,- or NaN
+  $x->digit($n);		# return the nth digit, counting from right
+  $x->digit(-$n);		# return the nth digit, counting from left 
 
   # The following all modify their first argument:
-
+  
   # set 
   $x->bzero();			# set $i to 0
   $x->bnan();			# set $i to NaN
+  $x->bone();                   # set $x to +1
+  $x->bone('-');                # set $x to -1
+  $x->binf();                   # set $x to inf
+  $x->binf('-');                # set $x to -inf
 
   $x->bneg();			# negation
   $x->babs();			# absolute value
@@ -1485,18 +1602,23 @@ Math::BigFloat - Arbitrary size floating point math package
   $x->bior($y);			# bit-wise inclusive or
   $x->bxor($y);			# bit-wise exclusive or
   $x->bnot();			# bit-wise not (two's complement)
-  
+ 
+  $x->bsqrt();			# calculate square-root
+  $x->bfac();			# factorial of $x (1*2*3*4*..$x)
+ 
   $x->bround($N); 		# accuracy: preserver $N digits
   $x->bfround($N);		# precision: round to the $Nth digit
 
   # The following do not modify their arguments:
-
   bgcd(@values);		# greatest common divisor
   blcm(@values);		# lowest common multiplicator
   
   $x->bstr();			# return string
   $x->bsstr();			# return string in scientific notation
-  
+ 
+  $x->bfloor();			# return integer less or equal than $x
+  $x->bceil();			# return integer greater or equal than $x
+ 
   $x->exponent();		# return exponent as BigInt
   $x->mantissa();		# return mantissa as BigInt
   $x->parts();			# return (mantissa,exponent) as BigInt
diff --git a/lib/Math/BigInt.pm b/lib/Math/BigInt.pm
index 516406b..c36014a 100644
--- a/lib/Math/BigInt.pm
+++ b/lib/Math/BigInt.pm
@@ -1,5 +1,3 @@
-#!/usr/bin/perl -w
-
 # The following hash values are used:
 #   value: unsigned int with actual value (as a Math::BigInt::Calc or similiar)
 #   sign : +,-,NaN,+inf,-inf
@@ -14,11 +12,12 @@ package Math::BigInt;
 my $class = "Math::BigInt";
 require 5.005;
 
-$VERSION = '1.49';
+$VERSION = '1.51';
 use Exporter;
 @ISA =       qw( Exporter );
 @EXPORT_OK = qw( objectify _swap bgcd blcm); 
 use vars qw/$round_mode $accuracy $precision $div_scale $rnd_mode/;
+use vars qw/$upgrade $downgrade/;
 use strict;
 
 # Inside overload, the first arg is always an object. If the original code had
@@ -57,6 +56,7 @@ use overload
 '|='	=>	sub { $_[0]->bior($_[1]); },
 '**='	=>	sub { $_[0]->bpow($_[1]); },
 
+# not supported by Perl yet
 '..'	=>	\&_pointpoint,
 
 '<=>'	=>	sub { $_[2] ?
@@ -64,13 +64,14 @@ use overload
                       ref($_[0])->bcmp($_[0],$_[1])},
 'cmp'	=>	sub {
          $_[2] ? 
-               $_[1] cmp $_[0]->bstr() :
-               $_[0]->bstr() cmp $_[1] },
+               "$_[1]" cmp $_[0]->bstr() :
+               $_[0]->bstr() cmp "$_[1]" },
 
 'log'	=>	sub { $_[0]->copy()->blog(); }, 
 'int'	=>	sub { $_[0]->copy(); }, 
 'neg'	=>	sub { $_[0]->copy()->bneg(); }, 
 'abs'	=>	sub { $_[0]->copy()->babs(); },
+'sqrt'  =>	sub { $_[0]->copy()->bsqrt(); },
 '~'	=>	sub { $_[0]->copy()->bnot(); },
 
 '*'	=>	sub { my @a = ref($_[0])->_swap(@_); $a[0]->bmul($a[1]); },
@@ -95,7 +96,7 @@ use overload
   # v5.6.1 dumps on that: return !$_[0]->is_zero() || undef;		    :-(
   my $t = !$_[0]->is_zero();
   undef $t if $t == 0;
-  return $t;
+  $t;
   },
 
 # the original qw() does not work with the TIESCALAR below, why?
@@ -114,13 +115,15 @@ my $nan = 'NaN'; 			# constants for easier life
 
 my $CALC = 'Math::BigInt::Calc';	# module to do low level math
 my $IMPORT = 0;				# did import() yet?
-sub _core_lib () { return $CALC; }	# for test suite
 
 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
 $accuracy   = undef;
 $precision  = undef;
 $div_scale  = 40;
 
+$upgrade = undef;			# default is no upgrade
+$downgrade = undef;			# default is no downgrade
+
 ##############################################################################
 # the old code had $rnd_mode, so we need to support it, too
 
@@ -144,11 +147,25 @@ sub round_mode
     my $m = shift;
     die "Unknown round mode $m"
      if $m !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/;
-    ${"${class}::round_mode"} = $m; return $m;
+    return ${"${class}::round_mode"} = $m;
     }
   return ${"${class}::round_mode"};
   }
 
+sub upgrade
+  {
+  no strict 'refs';
+  # make Class->round_mode() work
+  my $self = shift;
+  my $class = ref($self) || $self || __PACKAGE__;
+  if (defined $_[0])
+    {
+    my $u = shift;
+    return ${"${class}::upgrade"} = $u;
+    }
+  return ${"${class}::upgrade"};
+  }
+
 sub div_scale
   {
   no strict 'refs';
@@ -190,6 +207,7 @@ sub accuracy
       {
       # set global
       ${"${class}::accuracy"} = $a;
+      ${"${class}::precision"} = undef;	# clear P
       }
     return $a;				# shortcut
     }
@@ -222,12 +240,13 @@ sub precision
       # $object->precision() or fallback to global
       $x->bfround($p) if defined $p;
       $x->{_p} = $p;			# set/overwrite, even if not rounded
-      $x->{_a} = undef;			# clear P
+      $x->{_a} = undef;			# clear A
       }
     else
       {
       # set global
       ${"${class}::precision"} = $p;
+      ${"${class}::accuracy"} = undef;	# clear A
       }
     return $p;				# shortcut
     }
@@ -240,6 +259,26 @@ sub precision
   return ${"${class}::precision"};
   } 
 
+sub config
+  {
+  # return (later set?) configuration data as hash ref
+  my $class = shift || 'Math::BigInt';
+
+  no strict 'refs';
+  my $lib = $CALC;
+  my $cfg = {
+    lib => $lib,
+    lib_version => ${"${lib}::VERSION"},
+    class => $class,
+    };
+  foreach (
+   qw/upgrade downgrade precisison accuracy round_mode VERSION div_scale/)
+    {
+    $cfg->{lc($_)} = ${"${class}::$_"};
+    };
+  $cfg;
+  }
+
 sub _scale_a
   { 
   # select accuracy parameter based on precedence,
@@ -376,6 +415,7 @@ sub new
     if ($diff < 0)				# Not integer
       {
       #print "NOI 1\n";
+      return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
       $self->{sign} = $nan;
       }
     else					# diff >= 0
@@ -391,6 +431,7 @@ sub new
       {
       # fraction and negative/zero E => NOI
       #print "NOI 2 \$\$mfv '$$mfv'\n";
+      return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
       $self->{sign} = $nan;
       }
     elsif ($e < 0)
@@ -401,6 +442,7 @@ sub new
       if ($$miv !~ s/0{$e}$//)		# can strip so many zero's?
         {
         #print "NOI 3\n";
+        return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
         $self->{sign} = $nan;
         }
       }
@@ -411,6 +453,7 @@ sub new
   # do not round for new($x,undef,undef) since that is used by MBF to signal
   # no rounding
   $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
+  # print "mbi new $self\n";
   return $self;
   }
 
@@ -683,7 +726,7 @@ sub bnorm
   # (numstr or BINT) return BINT
   # Normalize number -- no-op here
   my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
-  return $x;
+  $x;
   }
 
 sub babs 
@@ -705,9 +748,9 @@ sub bneg
   my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
   
   return $x if $x->modify('bneg');
+
   # for +0 dont negate (to have always normalized)
-  return $x if $x->is_zero();
-  $x->{sign} =~ tr/+-/-+/;	# does nothing for NaN
+  $x->{sign} =~ tr/+-/-+/ if !$x->is_zero();	# does nothing for NaN
   $x;
   }
 
@@ -725,7 +768,7 @@ sub bcmp
     return +1 if $x->{sign} eq '+inf';
     return -1 if $x->{sign} eq '-inf';
     return -1 if $y->{sign} eq '+inf';
-    return +1 if $y->{sign} eq '-inf';
+    return +1;
     }
   # check sign for speed first
   return 1 if $x->{sign} eq '+' && $y->{sign} eq '-';	# does also 0 <=> -y
@@ -747,9 +790,7 @@ sub bcmp
 
   # $x->{sign} eq '-'
   return -1 if $y->{sign} eq '+';
-  return $CALC->_acmp($y->{value},$x->{value});	# swaped
-
-  # &cmp($x->{value},$y->{value},$x->{sign},$y->{sign}) <=> 0;
+  $CALC->_acmp($y->{value},$x->{value});	# swaped (lib does only 0,1,-1)
   }
 
 sub bacmp 
@@ -766,7 +807,7 @@ sub bacmp
     return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
     return +1;	# inf is always bigger
     }
-  $CALC->_acmp($x->{value},$y->{value}) <=> 0;
+  $CALC->_acmp($x->{value},$y->{value});	# lib does only 0,1,-1
   }
 
 sub badd 
@@ -776,6 +817,12 @@ sub badd
   my ($self,$x,$y,@r) = objectify(2,@_);
 
   return $x if $x->modify('badd');
+#  print "mbi badd ",join(' ',caller()),"\n";
+#  print "upgrade => ",$upgrade||'undef',
+#    " \$x (",ref($x),") \$y (",ref($y),")\n";
+#  return $upgrade->badd($x,$y,@r) if defined $upgrade &&
+#    ((ref($x) eq $upgrade) || (ref($y) eq $upgrade));
+#  print "still badd\n";
 
   $r[3] = $y;				# no push!
   # inf and NaN handling
@@ -786,9 +833,9 @@ sub badd
     # inf handline
    if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
       {
-      # + and + => +, - and - => -, + and - => 0, - and + => 0
-      return $x->bzero(@r) if $x->{sign} ne $y->{sign};
-      return $x;
+      # +inf++inf or -inf+-inf => same, rest is NaN
+      return $x if $x->{sign} eq $y->{sign};
+      return $x->bnan();
       }
     # +-inf + something => +inf
     # something +-inf => +-inf
@@ -796,16 +843,6 @@ sub badd
     return $x;
     }
     
-  # speed: no add for 0+y or x+0
-  return $x->round(@r) if $y->is_zero();			# x+0
-  if ($x->is_zero())						# 0+y
-    {
-    # make copy, clobbering up x
-    $x->{value} = $CALC->_copy($y->{value});
-    $x->{sign} = $y->{sign} || $nan;
-    return $x->round(@r);
-    }
-
   my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
 
   if ($sx eq $sy)  
@@ -843,16 +880,20 @@ sub bsub
   {
   # (BINT or num_str, BINT or num_str) return num_str
   # subtract second arg from first, modify first
-  my ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
+  my ($self,$x,$y,@r) = objectify(2,@_);
 
   return $x if $x->modify('bsub');
- 
-  if (!$y->is_zero())		# don't need to do anything if $y is 0
-    {
-    $y->{sign} =~ tr/+\-/-+/; 	# does nothing for NaN
-    $x->badd($y,$a,$p,$r); 	# badd does not leave internal zeros
-    $y->{sign} =~ tr/+\-/-+/; 	# refix $y (does nothing for NaN)
+#  return $upgrade->badd($x,$y,@r) if defined $upgrade &&
+#    ((ref($x) eq $upgrade) || (ref($y) eq $upgrade));
+
+  if ($y->is_zero())
+    { 
+    return $x->round(@r);
     }
+
+  $y->{sign} =~ tr/+\-/-+/; 	# does nothing for NaN
+  $x->badd($y,@r); 		# badd does not leave internal zeros
+  $y->{sign} =~ tr/+\-/-+/; 	# refix $y (does nothing for NaN)
   $x;				# already rounded by badd() or no round necc.
   }
 
@@ -905,8 +946,10 @@ sub bdec
 sub blog
   {
   # not implemented yet
-  my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
+  my ($self,$x,$base,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
  
+  return $upgrade->blog($x,$base,$a,$p,$r) if defined $upgrade;
+
   return $x->bnan();
   }
  
@@ -971,6 +1014,8 @@ sub bnot
   $x->bneg()->bdec();			# bdec already does round
   }
 
+# is_foo test routines
+
 sub is_zero
   {
   # return true if arg (BINT or num_str) is zero (array '+', '0')
@@ -1061,6 +1106,16 @@ sub is_negative
   0;
   }
 
+sub is_int
+  {
+  # return true when arg (BINT or num_str) is an integer
+  # always true for BigInt, but different for Floats
+  # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
+  my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+  
+  $x->{sign} =~ /^[+-]$/ ? 1 : 0;		# inf/-inf/NaN aren't
+  }
+
 ###############################################################################
 
 sub bmul 
@@ -1074,12 +1129,11 @@ sub bmul
   $r[3] = $y;				# no push here
  
   return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
-  # handle result = 0
-  return $x->round(@r) if $x->is_zero();
-  return $x->bzero()->round(@r) if $y->is_zero();
+
   # inf handling
   if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
     {
+    return $x->bnan() if $x->is_zero() || $y->is_zero();
     # result will always be +-inf:
     # +inf * +/+inf => +inf, -inf * -/-inf => +inf
     # +inf * -/-inf => -inf, -inf * +/+inf => -inf
@@ -1090,8 +1144,9 @@ sub bmul
 
   $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
 
-  $x->{value} = $CALC->_mul($x->{value},$y->{value});  # do actual math
-  return $x->round(@r);
+  $x->{value} = $CALC->_mul($x->{value},$y->{value});	# do actual math
+  $x->{sign} = '+' if $CALC->_is_zero($x->{value}); 	# no -0
+  $x->round(@r);
   }
 
 sub _div_inf
@@ -1104,17 +1159,10 @@ sub _div_inf
    if (($x->is_nan() || $y->is_nan())   ||
        ($x->is_zero() && $y->is_zero()));
  
-  # +inf / +inf == -inf / -inf == 1, remainder is 0 (A / A = 1, remainder 0)
-  if (($x->{sign} eq $y->{sign}) &&
-    ($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
-    {
-    return wantarray ? ($x->bone(),$self->bzero()) : $x->bone();
-    }
-  # +inf / -inf == -inf / +inf == -1, remainder 0
-  if (($x->{sign} ne $y->{sign}) &&
-    ($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
+  # +-inf / +-inf == NaN, reminder also NaN
+  if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
     {
-    return wantarray ? ($x->bone('-'),$self->bzero()) : $x->bone('-');
+    return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
     }
   # x / +-inf => 0, remainder x (works even if x == 0)
   if ($y->{sign} =~ /^[+-]inf$/)
@@ -1163,10 +1211,12 @@ sub bdiv
   return
    wantarray ? ($x->round(@r),$self->bzero(@r)):$x->round(@r) if $x->is_zero();
  
-  # Is $x in the interval [0, $y) ?
+  # Is $x in the interval [0, $y) (aka $x <= $y) ?
   my $cmp = $CALC->_acmp($x->{value},$y->{value});
-  if (($cmp < 0) and ($x->{sign} eq $y->{sign}))
+  if (($cmp < 0) and (($x->{sign} eq $y->{sign}) or !wantarray))
     {
+    return $upgrade->bdiv($x,$y,@r) if defined $upgrade;
+
     return $x->bzero()->round(@r) unless wantarray;
     my $t = $x->copy();      # make copy first, because $x->bzero() clobbers $x
     return ($x->bzero()->round(@r),$t);
@@ -1232,9 +1282,9 @@ sub bmod
     {
     # calc new sign and in case $y == +/- 1, return $x
     $x->{value} = $CALC->_mod($x->{value},$y->{value});
-    my $xsign = $x->{sign};
     if (!$CALC->_is_zero($x->{value}))
       {
+      my $xsign = $x->{sign};
       $x->{sign} = $y->{sign};
       $x = $y-$x if $xsign ne $y->{sign};	# one of them '-'
       }
@@ -1244,9 +1294,44 @@ sub bmod
       }
     return $x->round(@r);
     }
-  $x = (&bdiv($self,$x,$y,@r))[1];		# slow way (also rounds)
+  my ($t,$rem) = $self->bdiv($x->copy(),$y,@r);	# slow way (also rounds)
+  # modify in place
+  foreach (qw/value sign _a _p/)
+    {
+    $x->{$_} = $rem->{$_};
+    }
+  $x;
   }
 
+sub bfac
+  {
+  # (BINT or num_str, BINT or num_str) return BINT
+  # compute factorial numbers
+  # modifies first argument
+  my ($self,$x,@r) = objectify(1,@_);
+
+  return $x if $x->modify('bfac');
+ 
+  return $x->bnan() if $x->{sign} ne '+';	# inf, NnN, <0 etc => NaN
+  return $x->bone(@r) if $x->is_zero() || $x->is_one();		# 0 or 1 => 1
+
+  if ($CALC->can('_fac'))
+    {
+    $x->{value} = $CALC->_fac($x->{value});
+    return $x->round(@r);
+    }
+
+  my $n = $x->copy();
+  $x->bone();
+  my $f = $self->new(2);
+  while ($f->bacmp($n) < 0)
+    {
+    $x->bmul($f); $f->binc();
+    }
+  $x->bmul($f);					# last step
+  $x->round(@r);				# round
+  }
+ 
 sub bpow 
   {
   # (BINT or num_str, BINT or num_str) return BINT
@@ -1312,40 +1397,81 @@ sub blsft
   {
   # (BINT or num_str, BINT or num_str) return BINT
   # compute x << y, base n, y >= 0
-  my ($self,$x,$y,$n) = objectify(2,@_);
+  my ($self,$x,$y,$n,$a,$p,$r) = objectify(2,@_);
   
   return $x if $x->modify('blsft');
   return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
+  return $x->round($a,$p,$r) if $y->is_zero();
 
   $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
 
   my $t; $t = $CALC->_lsft($x->{value},$y->{value},$n) if $CALC->can('_lsft');
   if (defined $t)
     {
-    $x->{value} = $t; return $x;
+    $x->{value} = $t; return $x->round($a,$p,$r);
     }
   # fallback
-  return $x->bmul( $self->bpow($n, $y) );
+  return $x->bmul( $self->bpow($n, $y, $a, $p, $r), $a, $p, $r );
   }
 
 sub brsft 
   {
   # (BINT or num_str, BINT or num_str) return BINT
   # compute x >> y, base n, y >= 0
-  my ($self,$x,$y,$n) = objectify(2,@_);
+  my ($self,$x,$y,$n,$a,$p,$r) = objectify(2,@_);
 
   return $x if $x->modify('brsft');
   return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
+  return $x->round($a,$p,$r) if $y->is_zero();
+  return $x->bzero($a,$p,$r) if $x->is_zero();		# 0 => 0
 
   $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
 
+   # this only works for negative numbers when shifting in base 2
+  if (($x->{sign} eq '-') && ($n == 2))
+    {
+    return $x->round($a,$p,$r) if $x->is_one('-');	# -1 => -1
+    if (!$y->is_one())
+      {
+      # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
+      # but perhaps there is a better emulation for two's complement shift...
+      # if $y != 1, we must simulate it by doing:
+      # convert to bin, flip all bits, shift, and be done
+      $x->binc();			# -3 => -2
+      my $bin = $x->as_bin();
+      $bin =~ s/^-0b//;			# strip '-0b' prefix
+      $bin =~ tr/10/01/;		# flip bits
+      # now shift
+      if (length($bin) <= $y)
+        {
+	$bin = '0'; 			# shifting to far right creates -1
+					# 0, because later increment makes 
+					# that 1, attached '-' makes it '-1'
+					# because -1 >> x == -1 !
+        } 
+      else
+	{
+	$bin =~ s/.{$y}$//;		# cut off at the right side
+        $bin = '1' . $bin;		# extend left side by one dummy '1'
+        $bin =~ tr/10/01/;		# flip bits back
+	}
+      my $res = $self->new('0b'.$bin);	# add prefix and convert back
+      $res->binc();			# remember to increment
+      $x->{value} = $res->{value};	# take over value
+      return $x->round($a,$p,$r);	# we are done now, magic, isn't?
+      }
+    $x->bdec();				# n == 2, but $y == 1: this fixes it
+    }
+
   my $t; $t = $CALC->_rsft($x->{value},$y->{value},$n) if $CALC->can('_rsft');
   if (defined $t)
     {
-    $x->{value} = $t; return $x;
+    $x->{value} = $t;
+    return $x->round($a,$p,$r);
     }
   # fallback
-  return scalar bdiv($x, $self->bpow($n, $y));
+  $x->bdiv($self->bpow($n,$y, $a,$p,$r), $a,$p,$r);
+  $x;
   }
 
 sub band 
@@ -1356,6 +1482,8 @@ sub band
   
   return $x if $x->modify('band');
 
+  local $Math::BigInt::upgrade = undef;
+
   return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
   return $x->bzero() if $y->is_zero() || $x->is_zero();
 
@@ -1370,8 +1498,8 @@ sub band
     return $x->round($a,$p,$r);
     }
 
-  my $m = Math::BigInt->bone(); my ($xr,$yr);
-  my $x10000 = new Math::BigInt (0x1000);
+  my $m = $self->bone(); my ($xr,$yr);
+  my $x10000 = $self->new (0x1000);
   my $y1 = copy(ref($x),$y);	 		# make copy
   $y1->babs();					# and positive
   my $x1 = $x->copy()->babs(); $x->bzero();	# modify x in place!
@@ -1398,6 +1526,8 @@ sub bior
 
   return $x if $x->modify('bior');
 
+  local $Math::BigInt::upgrade = undef;
+
   return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
   return $x if $y->is_zero();
 
@@ -1413,8 +1543,8 @@ sub bior
     return $x->round($a,$p,$r);
     }
 
-  my $m = Math::BigInt->bone(); my ($xr,$yr);
-  my $x10000 = Math::BigInt->new(0x10000);
+  my $m = $self->bone(); my ($xr,$yr);
+  my $x10000 = $self->new(0x10000);
   my $y1 = copy(ref($x),$y);	 		# make copy
   $y1->babs();					# and positive
   my $x1 = $x->copy()->babs(); $x->bzero();	# modify x in place!
@@ -1441,6 +1571,8 @@ sub bxor
 
   return $x if $x->modify('bxor');
 
+  local $Math::BigInt::upgrade = undef;
+
   return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
   return $x if $y->is_zero();
   
@@ -1457,7 +1589,7 @@ sub bxor
     }
 
   my $m = $self->bone(); my ($xr,$yr);
-  my $x10000 = Math::BigInt->new(0x10000);
+  my $x10000 = $self->new(0x10000);
   my $y1 = copy(ref($x),$y);	 		# make copy
   $y1->babs();					# and positive
   my $x1 = $x->copy()->babs(); $x->bzero();	# modify x in place!
@@ -1513,10 +1645,13 @@ sub bsqrt
   {
   my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
 
+  return $x if $x->modify('bsqrt');
+
   return $x->bnan() if $x->{sign} ne '+';	# -x or inf or NaN => NaN
   return $x->bzero($a,$p) if $x->is_zero();			# 0 => 0
   return $x->round($a,$p,$r) if $x->is_one();			# 1 => 1
-  return $x->bone($a,$p) if $x < 4;				# 2,3 => 1
+
+  return $upgrade->bsqrt($x,$a,$p,$r) if defined $upgrade;
 
   if ($CALC->can('_sqrt'))
     {
@@ -1524,6 +1659,7 @@ sub bsqrt
     return $x->round($a,$p,$r);
     }
 
+  return $x->bone($a,$p) if $x < 4;				# 2,3 => 1
   my $y = $x->copy();
   my $l = int($x->length()/2);
   
@@ -1540,7 +1676,7 @@ sub bsqrt
     $x /= $two;
     }
   $x-- if $x * $x > $y;				# overshot?
-  return $x->round($a,$p,$r);
+  $x->round($a,$p,$r);
   }
 
 sub exponent
@@ -1594,6 +1730,7 @@ sub bfround
   my $x = shift; $x = $class->new($x) unless ref $x;
   my ($scale,$mode) = $x->_scale_p($x->precision(),$x->round_mode(),@_);
   return $x if !defined $scale;		# no-op
+  return $x if $x->modify('bfround');
 
   # no-op for BigInts if $n <= 0
   if ($scale <= 0)
@@ -1644,6 +1781,7 @@ sub bround
   my $x = shift; $x = $class->new($x) unless ref $x;
   my ($scale,$mode) = $x->_scale_a($x->accuracy(),$x->round_mode(),@_);
   return $x if !defined $scale;			# no-op
+  return $x if $x->modify('bround');
   
   if ($x->is_zero() || $scale == 0)
     {
@@ -1916,11 +2054,18 @@ sub import
       overload::constant integer => sub { $self->new(shift) };
       splice @a, $j, 1; $j --;
       }
+    elsif ($_[$i] eq 'upgrade')
+      {
+      # this causes upgrading
+      $upgrade = $_[$i+1];		# or undef to disable
+      my $s = 2; $s = 1 if @a-$j < 2;	# avoid "can not modify non-existant..."
+      splice @a, $j, $s; $j -= $s;
+      }
     elsif ($_[$i] =~ /^lib$/i)
       {
       # this causes a different low lib to take care...
       $CALC = $_[$i+1] || '';
-      my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
+      my $s = 2; $s = 1 if @a-$j < 2;	# avoid "can not modify non-existant..."
       splice @a, $j, $s; $j -= $s;
       }
     }
@@ -2236,6 +2381,7 @@ Math::BigInt - Arbitrary size integer math package
   $x->is_positive();		# true if >= 0
   $x->is_negative();		# true if <  0
   $x->is_inf(sign);		# true if +inf, or -inf (sign is default '+')
+  $x->is_int();			# true if $x is an integer (not a float)
 
   $x->bcmp($y);			# compare numbers (undef,<0,=0,>0)
   $x->bacmp($y);		# compare absolutely (undef,<0,=0,>0)
@@ -2250,6 +2396,8 @@ Math::BigInt - Arbitrary size integer math package
   $x->bnan();			# set $x to NaN
   $x->bone();			# set $x to +1
   $x->bone('-');		# set $x to -1
+  $x->binf();			# set $x to inf
+  $x->binf('-');		# set $x to -inf
 
   $x->bneg();			# negation
   $x->babs();			# absolute value
@@ -2277,6 +2425,7 @@ Math::BigInt - Arbitrary size integer math package
   $x->bnot();			# bitwise not (two's complement)
 
   $x->bsqrt();			# calculate square-root
+  $x->bfac();			# factorial of $x (1*2*3*4*..$x)
 
   $x->round($A,$P,$round_mode); # round to accuracy or precision using mode $r
   $x->bround($N);               # accuracy: preserve $N digits
@@ -2355,6 +2504,291 @@ return either undef, <0, 0 or >0 and are suited for sort.
 
 =back
 
+=head1 METHODS
+
+Each of the methods below accepts three additional parameters. These arguments
+$A, $P and $R are accuracy, precision and round_mode. Please see more in the
+section about ACCURACY and ROUNDIND.
+
+=head2 brsft
+
+	$x->brsft($y,$n);		
+
+Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
+2, but others work, too.
+
+Right shifting usually amounts to dividing $x by $n ** $y and truncating the
+result:
+
+
+	$x = Math::BigInt->new(10);
+	$x->brsft(1);			# same as $x >> 1: 5
+	$x = Math::BigInt->new(1234);
+	$x->brsft(2,10);		# result 12
+
+There is one exception, and that is base 2 with negative $x:
+
+
+	$x = Math::BigInt->new(-5);
+	print $x->brsft(1);
+
+This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
+result).
+
+=head2 new
+
+  	$x = Math::BigInt->new($str,$A,$P,$R);
+
+Creates a new BigInt object from a string or another BigInt object. The
+input is accepted as decimal, hex (with leading '0x') or binary (with leading
+'0b').
+
+=head2 bnan
+
+  	$x = Math::BigInt->bnan();
+
+Creates a new BigInt object representing NaN (Not A Number).
+If used on an object, it will set it to NaN:
+
+	$x->bnan();
+
+=head2 bzero
+
+  	$x = Math::BigInt->bzero();
+
+Creates a new BigInt object representing zero.
+If used on an object, it will set it to zero:
+
+	$x->bzero();
+
+=head2 binf
+
+  	$x = Math::BigInt->binf($sign);
+
+Creates a new BigInt object representing infinity. The optional argument is
+either '-' or '+', indicating whether you want infinity or minus infinity.
+If used on an object, it will set it to infinity:
+
+	$x->binf();
+	$x->binf('-');
+
+=head2 bone
+
+  	$x = Math::BigInt->binf($sign);
+
+Creates a new BigInt object representing one. The optional argument is
+either '-' or '+', indicating whether you want one or minus one.
+If used on an object, it will set it to one:
+
+	$x->bone();		# +1
+	$x->bone('-');		# -1
+
+=head2 is_one()/is_zero()/is_nan()/is_positive()/is_negative()/is_inf()/is_odd()/is_even()/is_int()
+  
+	$x->is_zero();			# true if arg is +0
+	$x->is_nan();			# true if arg is NaN
+	$x->is_one();			# true if arg is +1
+	$x->is_one('-');		# true if arg is -1
+	$x->is_odd();			# true if odd, false for even
+	$x->is_even();			# true if even, false for odd
+	$x->is_positive();		# true if >= 0
+	$x->is_negative();		# true if <  0
+	$x->is_inf();			# true if +inf
+	$x->is_inf('-');		# true if -inf (sign is default '+')
+	$x->is_int();			# true if $x is an integer
+
+These methods all test the BigInt for one condition and return true or false
+depending on the input.
+
+=head2 bcmp
+
+  $x->bcmp($y);			# compare numbers (undef,<0,=0,>0)
+
+=head2 bacmp
+
+  $x->bacmp($y);		# compare absolutely (undef,<0,=0,>0)
+
+=head2 sign
+
+  $x->sign();			# return the sign, either +,- or NaN
+
+=head2 bcmp
+
+  $x->digit($n);		# return the nth digit, counting from right
+
+=head2 bneg
+
+	$x->bneg();
+
+Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
+and '-inf', respectively. Does nothing for NaN or zero.
+
+=head2 babs
+
+	$x->babs();
+
+Set the number to it's absolute value, e.g. change the sign from '-' to '+'
+and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
+numbers.
+
+=head2 bnorm
+
+  $x->bnorm();			# normalize (no-op)
+
+=head2 bnot
+
+  $x->bnot();			# two's complement (bit wise not)
+
+=head2 binc
+
+  $x->binc();			# increment x by 1
+
+=head2 bdec
+
+  $x->bdec();			# decrement x by 1
+
+=head2 badd
+
+  $x->badd($y);			# addition (add $y to $x)
+
+=head2 bsub
+
+  $x->bsub($y);			# subtraction (subtract $y from $x)
+
+=head2 bmul
+
+  $x->bmul($y);			# multiplication (multiply $x by $y)
+
+=head2 bdiv
+
+  $x->bdiv($y);			# divide, set $x to quotient
+				# return (quo,rem) or quo if scalar
+
+=head2 bmod
+
+  $x->bmod($y);			# modulus (x % y)
+
+=head2 bpow
+
+  $x->bpow($y);			# power of arguments (x ** y)
+
+=head2 blsft
+
+  $x->blsft($y);		# left shift
+  $x->blsft($y,$n);		# left shift, by base $n (like 10)
+
+=head2 brsft
+
+  $x->brsft($y);		# right shift 
+  $x->brsft($y,$n);		# right shift, by base $n (like 10)
+
+=head2 band
+
+  $x->band($y);			# bitwise and
+
+=head2 bior
+
+  $x->bior($y);			# bitwise inclusive or
+
+=head2 bxor
+
+  $x->bxor($y);			# bitwise exclusive or
+
+=head2 bnot
+
+  $x->bnot();			# bitwise not (two's complement)
+
+=head2 bsqrt
+
+  $x->bsqrt();			# calculate square-root
+
+=head2 bfac
+
+  $x->bfac();			# factorial of $x (1*2*3*4*..$x)
+
+=head2 round
+
+  $x->round($A,$P,$round_mode); # round to accuracy or precision using mode $r
+
+=head2 bround
+
+  $x->bround($N);               # accuracy: preserve $N digits
+
+=head2 bfround
+
+  $x->bfround($N);              # round to $Nth digit, no-op for BigInts
+
+=head2 bfloor
+
+	$x->bfloor();			
+
+Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
+does change $x in BigFloat.
+
+=head2 bceil
+
+	$x->bceil();
+
+Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
+does change $x in BigFloat.
+
+=head2 bgcd
+
+  bgcd(@values);		# greatest common divisor (no OO style)
+
+=head2 blcm
+
+  blcm(@values);		# lowest common multiplicator (no OO style)
+ 
+head2 length
+
+	$x->length();
+        ($xl,$fl) = $x->length();
+
+Returns the number of digits in the decimal representation of the number.
+In list context, returns the length of the integer and fraction part. For
+BigInt's, the length of the fraction part will always be 0.
+
+=head2 exponent
+
+	$x->exponent();
+
+Return the exponent of $x as BigInt.
+
+=head2 mantissa
+
+	$x->mantissa();
+
+Return the signed mantissa of $x as BigInt.
+
+=head2 parts
+
+  $x->parts();			# return (mantissa,exponent) as BigInt
+
+=head2 copy
+
+  $x->copy();			# make a true copy of $x (unlike $y = $x;)
+
+=head2 as_number
+
+  $x->as_number();		# return as BigInt (in BigInt: same as copy())
+  
+=head2 bsrt
+
+  $x->bstr();			# normalized string
+
+=head2 bsstr
+
+  $x->bsstr();			# normalized string in scientific notation
+
+=head2 as_hex
+
+  $x->as_hex();			# as signed hexadecimal string with prefixed 0x
+
+=head2 as_bin
+
+  $x->as_bin();			# as signed binary string with prefixed 0b
+
 =head1 ACCURACY and PRECISION
 
 Since version v1.33, Math::BigInt and Math::BigFloat have full support for
@@ -2534,29 +2968,48 @@ This is how it works now:
 
 =item Setting/Accessing
 
-  * You can set the A global via $Math::BigInt::accuracy or
-    $Math::BigFloat::accuracy or whatever class you are using.
-  * You can also set P globally by using $Math::SomeClass::precision likewise.
+  * You can set the A global via Math::BigInt->accuracy() or
+    Math::BigFloat->accuracy() or whatever class you are using.
+  * You can also set P globally by using Math::SomeClass->precision() likewise.
   * Globals are classwide, and not inherited by subclasses.
-  * to undefine A, use $Math::SomeCLass::accuracy = undef
-  * to undefine P, use $Math::SomeClass::precision = undef
+  * to undefine A, use Math::SomeCLass->accuracy(undef);
+  * to undefine P, use Math::SomeClass->precision(undef);
+  * Setting Math::SomeClass->accuracy() clears automatically
+    Math::SomeClass->precision(), and vice versa.
   * To be valid, A must be > 0, P can have any value.
   * If P is negative, this means round to the P'th place to the right of the
     decimal point; positive values mean to the left of the decimal point.
     P of 0 means round to integer.
-  * to find out the current global A, take $Math::SomeClass::accuracy
-  * use $x->accuracy() for the local setting of $x.
-  * to find out the current global P, take $Math::SomeClass::precision
-  * use $x->precision() for the local setting
+  * to find out the current global A, take Math::SomeClass->accuracy()
+  * to find out the current global P, take Math::SomeClass->precision()
+  * use $x->accuracy() respective $x->precision() for the local setting of $x.
+  * Please note that $x->accuracy() respecive $x->precision() fall back to the
+    defined globals, when $x's A or P is not set.
 
 =item Creating numbers
 
- !* When you create a number, there should be a way to define its A & P
-  * When a number without specific A or P is created, but the globals are
-    defined, these should be used to round the number immediately and also
-    stored locally with the number. Thus changing the global defaults later on
+  * When you create a number, you can give it's desired A or P via:
+    $x = Math::BigInt->new($number,$A,$P);
+  * Only one of A or P can be defined, otherwise the result is NaN
+  * If no A or P is give ($x = Math::BigInt->new($number) form), then the
+    globals (if set) will be used. Thus changing the global defaults later on
     will not change the A or P of previously created numbers (i.e., A and P of
-    $x will be what was in effect when $x was created) 
+    $x will be what was in effect when $x was created)
+  * If given undef for A and P, B<no> rounding will occur, and the globals will
+    B<not> be used. This is used by subclasses to create numbers without
+    suffering rounding in the parent. Thus a subclass is able to have it's own
+    globals enforced upon creation of a number by using
+    $x = Math::BigInt->new($number,undef,undef):
+
+	use Math::Bigint::SomeSubclass;
+	use Math::BigInt;
+
+	Math::BigInt->accuracy(2);
+	Math::BigInt::SomeSubClass->accuracy(3);
+	$x = Math::BigInt::SomeSubClass->new(1234);	
+
+    $x is now 1230, and not 1200. A subclass might choose to implement
+    this otherwise, e.g. falling back to the parent's A and P.
 
 =item Usage
 
@@ -2574,9 +3027,8 @@ This is how it works now:
     Since you can set/get both A and P, there is a rule that will practically
     enforce only A or P to be in effect at a time, even if both are set.
     This is called precedence.
- !* If two objects are involved in an operation, and one of them has A in
- !  effect, and the other P, this should result in a warning or an error,
- !  probably in NaN.
+  * If two objects are involved in an operation, and one of them has A in
+    effect, and the other P, this results in an error (NaN).
   * A takes precendence over P (Hint: A comes before P). If A is defined, it
     is used, otherwise P is used. If neither of them is defined, nothing is
     used, i.e. the result will have as many digits as it can (with an
@@ -2587,7 +3039,7 @@ This is how it works now:
     the value of F, the higher value will be used instead of F.
     This is to limit the digits (A) of the result (just consider what would
     happen with unlimited A and P in the case of 1/3 :-)
-  * fdiv will calculate 1 more digit than required (determined by
+  * fdiv will calculate (at least) 4 more digits than required (determined by
     A, P or F), and, if F is not used, round the result
     (this will still fail in the case of a result like 0.12345000000001 with A
     or P of 5, but this can not be helped - or can it?)
@@ -2623,7 +3075,7 @@ This is how it works now:
 
   * you will be able to give A, P and R as an argument to all the calculation
     routines; the second parameter is A, the third one is P, and the fourth is
-    R (shift place by one for binary operations like add). P is used only if
+    R (shift right by one for binary operations like badd). P is used only if
     the first parameter (A) is undefined. These three parameters override the
     globals in the order detailed as follows, i.e. the first defined value
     wins:
@@ -2631,7 +3083,7 @@ This is how it works now:
       + parameter A
       + parameter P
       + local A (if defined on both of the operands: smaller one is taken)
-      + local P (if defined on both of the operands: smaller one is taken)
+      + local P (if defined on both of the operands: bigger one is taken)
       + global A
       + global P
       + global F
@@ -2643,6 +3095,7 @@ This is how it works now:
   * You can set A and P locally by using $x->accuracy() and $x->precision()
     and thus force different A and P for different objects/numbers.
   * Setting A or P this way immediately rounds $x to the new value.
+  * $x->accuracy() clears $x->precision(), and vice versa.
 
 =item Rounding
 
@@ -2710,10 +3163,10 @@ Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
 	use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
 
 Calc.pm uses as internal format an array of elements of some decimal base
-(usually 1e5, but this might change to 1e7) with the least significant digit
-first, while BitVect.pm uses a bit vector of base 2, most significant bit
-first. Other modules might use even different means of representing the
-numbers. See the respective module documentation for further details.
+(usually 1e5 or 1e7) with the least significant digit first, while BitVect.pm
+uses a bit vector of base 2, most significant bit first. Other modules might
+use even different means of representing the numbers. See the respective
+module documentation for further details.
 
 =head2 SIGN
 
@@ -2869,6 +3322,116 @@ See L<MATH LIBRARY> for more information.
 
 For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
 
+=head2 SUBCLASSING
+
+=head1 Subclassing Math::BigInt
+
+The basic design of Math::BigInt allows simple subclasses with very little
+work, as long as a few simple rules are followed:
+
+=over 2
+
+=item *
+
+The public API must remain consistent, i.e. if a sub-class is overloading
+addition, the sub-class must use the same name, in this case badd(). The
+reason for this is that Math::BigInt is optimized to call the object methods
+directly.
+
+=item *
+
+The private object hash keys like C<$x->{sign}> may not be changed, but
+additional keys can be added, like C<$x->{_custom}>.
+
+=item *
+
+Accessor functions are available for all existing object hash keys and should
+be used instead of directly accessing the internal hash keys. The reason for
+this is that Math::BigInt itself has a pluggable interface which permits it
+to support different storage methods.
+
+=back
+
+More complex sub-classes may have to replicate more of the logic internal of
+Math::BigInt if they need to change more basic behaviors. A subclass that
+needs to merely change the output only needs to overload C<bstr()>. 
+
+All other object methods and overloaded functions can be directly inherited
+from the parent class.
+
+At the very minimum, any subclass will need to provide it's own C<new()> and can
+store additional hash keys in the object. There are also some package globals
+that must be defined, e.g.:
+
+  # Globals
+  $accuracy = undef;
+  $precision = -2;       # round to 2 decimal places
+  $round_mode = 'even';
+  $div_scale = 40;
+
+Additionally, you might want to provide the following two globals to allow
+auto-upgrading and auto-downgrading to work correctly:
+
+  $upgrade = undef;
+  $downgrade = undef;
+
+This allows Math::BigInt to correctly retrieve package globals from the 
+subclass, like C<$SubClass::precision>.  See t/Math/BigInt/Subclass.pm or
+t/Math/BigFloat/SubClass.pm completely functional subclass examples.
+
+Don't forget to 
+
+	use overload;
+
+in your subclass to automatically inherit the overloading from the parent. If
+you like, you can change part of the overloading, look at Math::String for an
+example.
+
+=head1 UPGRADING
+
+When used like this:
+
+	use Math::BigInt upgrade => 'Foo::Bar';
+
+certain operations will 'upgrade' their calculation and thus the result to
+the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
+
+	use Math::BigInt upgrade => 'Math::BigFloat';
+
+As a shortcut, you can use the module C<bignum>:
+
+	use bignum;
+
+Also good for oneliners:
+
+	perl -Mbignum -le 'print 2 ** 255'
+
+This makes it possible to mix arguments of different classes (as in 2.5 + 2)
+as well es preserve accuracy (as in sqrt(3)).
+
+Beware: This feature is not fully implemented yet.
+
+=head2 Auto-upgrade
+
+The following methods upgrade themselves unconditionally; that is if upgrade
+is in effect, they will always hand up their work:
+
+=over 2
+
+=item bsqrt()
+
+=item div()
+
+=item blog()
+
+=back
+
+Beware: This list is not complete.
+
+All other methods upgrade themselves only when one (or all) of their
+arguments are of the class mentioned in $upgrade (This might change in later
+versions to a more sophisticated scheme):
+
 =head1 BUGS
 
 =over 2
@@ -3180,6 +3743,8 @@ will both result in the proper type due to the way the overloaded math works.
 
 This section also applies to other overloaded math packages, like Math::String.
 
+One solution to you problem might be L<autoupgrading|upgrading>.
+
 =item bsqrt()
 
 C<bsqrt()> works only good if the result is a big integer, e.g. the square
@@ -3197,6 +3762,10 @@ If you want a better approximation of the square root, then use:
 	print $x->bsqrt(),"\n";			# 3.46
 	print $x->bsqrt(3),"\n";		# 3.464
 
+=item brsft()
+
+For negative numbers in base see also L<brsft|brsft>.
+
 =back
 
 =head1 LICENSE
diff --git a/lib/Math/BigInt/Calc.pm b/lib/Math/BigInt/Calc.pm
index d91272e..d76aa09 100644
--- a/lib/Math/BigInt/Calc.pm
+++ b/lib/Math/BigInt/Calc.pm
@@ -8,7 +8,7 @@ require Exporter;
 use vars qw/@ISA $VERSION/;
 @ISA = qw(Exporter);
 
-$VERSION = '0.20';
+$VERSION = '0.22';
 
 # Package to store unsigned big integers in decimal and do math with them
 
@@ -330,6 +330,13 @@ sub _add
   # This routine clobbers up array x, but not y.
  
   my ($c,$x,$y) = @_;
+
+  return $x if (@$y == 1) && $y->[0] == 0;		# $x + 0 => $x
+  if ((@$x == 1) && $x->[0] == 0)			# 0 + $y => $y->copy
+    {
+    # twice as slow as $x = [ @$y ], but necc. to retain $x as ref :(
+    @$x = @$y; return $x;		
+    }
  
   # for each in Y, add Y to X and carry. If after that, something is left in
   # X, foreach in X add carry to X and then return X, carry
@@ -419,17 +426,24 @@ sub _mul_use_mul
   # modifies first arg, second need not be different from first
   my ($c,$xv,$yv) = @_;
 
-  # shortcut for two very short numbers
-  # +0 since part maybe string '00001' from new()
+  # shortcut for two very short numbers (improved by Nathan Zook)
   # works also if xv and yv are the same reference
-  if ((@$xv == 1) && (@$yv == 1)
-   && (length($xv->[0]+0) <= $BASE_LEN2)
-   && (length($yv->[0]+0) <= $BASE_LEN2))
-   {
-   $xv->[0] *= $yv->[0];
-   return $xv;
-   }
-  
+  if ((@$xv == 1) && (@$yv == 1))
+    {
+    if (($xv->[0] *= $yv->[0]) >= $MBASE)
+       {
+       $xv->[0] = $xv->[0] - ($xv->[1] = int($xv->[0] * $RBASE)) * $MBASE;
+       };
+    return $xv;
+    }
+  # shortcut for result == 0
+  if ( ((@$xv == 1) && ($xv->[0] == 0)) ||
+       ((@$yv == 1) && ($yv->[0] == 0)) )
+    {
+    @$xv = (0);
+    return $xv;
+    }
+
   # since multiplying $x with $x fails, make copy in this case
   $yv = [@$xv] if "$xv" eq "$yv";	# same references?
   if ($LEN_CONVERT != 0)
@@ -487,16 +501,25 @@ sub _mul_use_div
   # modifies first arg, second need not be different from first
   my ($c,$xv,$yv) = @_;
  
-  # shortcut for two very short numbers
-  # +0 since part maybe string '00001' from new()
+  # shortcut for two very short numbers (improved by Nathan Zook)
   # works also if xv and yv are the same reference
-  if ((@$xv == 1) && (@$yv == 1)
-   && (length($xv->[0]+0) <= $BASE_LEN2)
-   && (length($yv->[0]+0) <= $BASE_LEN2))
-   {
-   $xv->[0] *= $yv->[0];
-   return $xv;
-   }
+  if ((@$xv == 1) && (@$yv == 1))
+    {
+    if (($xv->[0] *= $yv->[0]) >= $MBASE)
+        {
+        $xv->[0] =
+            $xv->[0] - ($xv->[1] = int($xv->[0] / $MBASE)) * $MBASE;
+        };
+    return $xv;
+    }
+  # shortcut for result == 0
+  if ( ((@$xv == 1) && ($xv->[0] == 0)) ||
+       ((@$yv == 1) && ($yv->[0] == 0)) )
+    {
+    @$xv = (0);
+    return $xv;
+    }
+
  
   # since multiplying $x with $x fails, make copy in this case
   $yv = [@$xv] if "$xv" eq "$yv";	# same references?
@@ -1122,7 +1145,50 @@ sub _pow
   $cx;
   }
 
-sub _sqrt1
+sub _fac
+  {
+  # factorial of $x
+  # ref to array, return ref to array
+  my ($c,$cx) = @_;
+
+  if ((@$cx == 1) && ($cx->[0] <= 2))
+    {
+    $cx->[0] = 1 * ($cx->[0]||1); # 0,1 => 1, 2 => 2
+    return $cx;
+    }
+
+  # go forward until $base is exceeded
+  # limit is either $x or $base (x == 100 means as result too high)
+  my $steps = 100; $steps = $cx->[0] if @$cx == 1;
+  my $r = 2; my $cf = 3; my $step = 1; my $last = $r;
+  while ($r < $BASE && $step < $steps)
+    {
+    $last = $r; $r *= $cf++; $step++;
+    }
+  if ((@$cx == 1) && ($step == $cx->[0]))
+    {
+    # completely done
+    $cx = [$last];
+    return $cx;
+    }
+  my $n = _copy($c,$cx);
+  $cx = [$last];
+
+  #$cx = _one();
+  while (!(@$n == 1 && $n->[0] == $step))
+    {
+    _mul($c,$cx,$n); _dec($c,$n);
+    }
+  $cx;
+  }
+
+use constant DEBUG => 0;
+
+my $steps = 0;
+
+sub steps { $steps };
+
+sub _sqrt
   {
   # square-root of $x
   # ref to array, return ref to array
@@ -1135,31 +1201,68 @@ sub _sqrt1
     return $x;
     } 
   my $y = _copy($c,$x);
-  my $l = _len($c,$x) / 2;	# hopefully _len/2 is < $BASE
-  # my $l2 = [ _len($c,$x) / 2 ];	# old way: hopefully _len/2 is < $BASE
-
-  splice @$x,0; $x->[0] = 1; 	# keep ref($x), but modify it
-
-  # old way
-  # _lsft($c,$x,$l2,10);
+  # hopefully _len/2 is < $BASE, the -1 is to always undershot the guess
+  # since our guess will "grow"
+  my $l = int((_len($c,$x)-1) / 2);	
+
+  my $lastelem = $x->[-1];	# for guess
+  my $elems = scalar @$x - 1;
+  # not enough digits, but could have more?
+  if ((length($lastelem) <= 3) && ($elems > 1))	
+    {
+    # right-align with zero pad
+    my $len = length($lastelem) & 1;
+    print "$lastelem => " if DEBUG;
+    $lastelem .= substr($x->[-2] . '0' x $BASE_LEN,0,$BASE_LEN);
+    # former odd => make odd again, or former even to even again
+    $lastelem = $lastelem / 10 if (length($lastelem) & 1) != $len;	
+    print "$lastelem\n" if DEBUG;
+    }
 
   # construct $x (instead of _lsft($c,$x,$l,10)
   my $r = $l % $BASE_LEN;	# 10000 00000 00000 00000 ($BASE_LEN=5)
   $l = int($l / $BASE_LEN);
-  $x->[$l--] = int('1' . '0' x $r);
-  $x->[$l--] = 0 while ($l >= 0);
+  print "l =  $l " if DEBUG;
+  
+  splice @$x,$l; 		# keep ref($x), but modify it
+ 
+  # we make the first part of the guess not '1000...0' but int(sqrt($lastelem))
+  # that gives us:
+  # 14400 00000 => sqrt(14400) => 120
+  # 144000 000000 => sqrt(144000) => 379
+
+  # $x->[$l--] = int('1' . '0' x $r);			# old way of guessing
+  print "$lastelem (elems $elems) => " if DEBUG;
+  $lastelem = $lastelem / 10 if ($elems & 1 == 1);		# odd or even?
+  my $g = sqrt($lastelem); $g =~ s/\.//;			# 2.345 => 2345
+  $r -= 1 if $elems & 1 == 0;					# 70 => 7
+
+  # padd with zeros if result is too short
+  $x->[$l--] = int(substr($g . '0' x $r,0,$r+1));
+  print "now ",$x->[-1] if DEBUG;
+  print " would have been ", int('1' . '0' x $r),"\n" if DEBUG;
+  
+  # If @$x > 1, we could compute the second elem of the guess, too, to create
+  # an even better guess. Not implemented yet.
+  $x->[$l--] = 0 while ($l >= 0);	# all other digits of guess are zero
  
+  print "start x= ",${_str($c,$x)},"\n" if DEBUG;
   my $two = _two();
   my $last = _zero();
   my $lastlast = _zero();
+  $steps = 0 if DEBUG;
   while (_acmp($c,$last,$x) != 0 && _acmp($c,$lastlast,$x) != 0)
     {
+    $steps++ if DEBUG;
     $lastlast = _copy($c,$last);
     $last = _copy($c,$x);
     _add($c,$x, _div($c,_copy($c,$y),$x));
     _div($c,$x, $two );
+    print "      x= ",${_str($c,$x)},"\n" if DEBUG;
     }
+  print "\nsteps in sqrt: $steps, " if DEBUG;
   _dec($c,$x) if _acmp($c,$y,_mul($c,_copy($c,$x),$x)) < 0;	# overshot? 
+  print " final ",$x->[-1],"\n" if DEBUG;
   $x;
   }
 
@@ -1466,6 +1569,7 @@ slow) fallback routines to emulate these:
 
 	_mod(obj,obj)	Return remainder of div of the 1st by the 2nd object
 	_sqrt(obj)	return the square root of object (truncate to int)
+	_fac(obj)	return factorial of object 1 (1*2*3*4..)
 	_pow(obj,obj)	return object 1 to the power of object 2
 	_gcd(obj,obj)	return Greatest Common Divisor of two objects
 	
diff --git a/lib/Math/BigInt/t/bare_mbf.t b/lib/Math/BigInt/t/bare_mbf.t
new file mode 100644
index 0000000..2e669f8
--- /dev/null
+++ b/lib/Math/BigInt/t/bare_mbf.t
@@ -0,0 +1,39 @@
+#!/usr/bin/perl -w
+
+use Test;
+use strict;
+
+BEGIN
+  {
+  $| = 1;
+  # to locate the testing files
+  my $location = $0; $location =~ s/bare_mbf.t//i;
+  if ($ENV{PERL_CORE})
+    {
+    # testing with the core distribution
+    @INC = qw(../t/lib);
+    }
+  unshift @INC, '../lib';
+  if (-d 't')
+    {
+    chdir 't';
+    require File::Spec;
+    unshift @INC, File::Spec->catdir(File::Spec->updir, $location);
+    }
+  else
+    {
+    unshift @INC, $location;
+    }
+  print "# INC = @INC\n";
+
+  plan tests => 1585;
+  }
+
+use Math::BigInt lib => 'BareCalc';
+use Math::BigFloat;
+
+use vars qw ($class $try $x $y $f @args $ans $ans1 $ans1_str $setup $CL);
+$class = "Math::BigFloat";
+$CL = "Math::BigInt::BareCalc";
+   
+require 'bigfltpm.inc';	# all tests here for sharing
diff --git a/lib/Math/BigInt/t/bare_mbi.t b/lib/Math/BigInt/t/bare_mbi.t
index 5b2df41..b5ffa9d 100644
--- a/lib/Math/BigInt/t/bare_mbi.t
+++ b/lib/Math/BigInt/t/bare_mbi.t
@@ -26,18 +26,18 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 2005;
+  plan tests => 2095;
   }
 
 use Math::BigInt lib => 'BareCalc';
 
-print "# ",Math::BigInt::_core_lib(),"\n";
+print "# ",Math::BigInt->config()->{lib},"\n";
 
 use vars qw ($class $try $x $y $f @args $ans $ans1 $ans1_str $setup $CL);
 $class = "Math::BigInt";
 $CL = "Math::BigInt::BareCalc";
 
-my $version = '1.49';   # for $VERSION tests, match current release (by hand!)
+my $version = '1.51';   # for $VERSION tests, match current release (by hand!)
 
 require 'bigintpm.inc';	# perform same tests as bigintpm
 
diff --git a/lib/Math/BigInt/t/bigfltpm.inc b/lib/Math/BigInt/t/bigfltpm.inc
index a5e527e..e7860d3 100644
--- a/lib/Math/BigInt/t/bigfltpm.inc
+++ b/lib/Math/BigInt/t/bigfltpm.inc
@@ -1,4 +1,7 @@
 #include this file into another test for subclass testing...
+
+ok ($class->config()->{lib},$CL);
+
 while (<DATA>)
   {
   chop;
@@ -52,11 +55,11 @@ while (<DATA>)
         $try .= "\$x->numify();";
       } elsif ($f eq "length") {
         $try .= "\$x->length();";
-      # some unary ops (test the bxxx form, since that is done by AUTOLOAD)
+      # some unary ops (test the fxxx form, since that is done by AUTOLOAD)
       } elsif ($f =~ /^f(nan|sstr|neg|floor|ceil|abs)$/) {
         $try .= "\$x->f$1();";
       # some is_xxx test function	
-      } elsif ($f =~ /^is_(zero|one|negative|positive|odd|even|nan)$/) {
+      } elsif ($f =~ /^is_(zero|one|negative|positive|odd|even|nan|int)$/) {
         $try .= "\$x->$f();";
       } elsif ($f eq "as_number") {
         $try .= '$x->as_number();';
@@ -70,14 +73,16 @@ while (<DATA>)
         $try .= "$setup; \$x->ffround($args[1]);";
       } elsif ($f eq "fsqrt") {
         $try .= "$setup; \$x->fsqrt();";
+      } elsif ($f eq "flog") {
+        $try .= "$setup; \$x->flog();";
+      } elsif ($f eq "ffac") {
+        $try .= "$setup; \$x->ffac();";
       }
     else
       {
       $try .= "\$y = new $class \"$args[1]\";";
       if ($f eq "fcmp") {
         $try .= '$x <=> $y;';
-      } elsif ($f eq "flog") {
-        $try .= '$x->flog($y);';
       } elsif ($f eq "facmp") {
         $try .= '$x->facmp($y);';
       } elsif ($f eq "fpow") {
@@ -90,6 +95,8 @@ while (<DATA>)
         $try .= '$x * $y;';
       } elsif ($f eq "fdiv") {
         $try .= "$setup; \$x / \$y;";
+      } elsif ($f eq "fdiv-list") {
+        $try .= "$setup; join(',',\$x->fdiv(\$y));";
       } elsif ($f eq "frsft") {
         $try .= '$x >> $y;';
       } elsif ($f eq "flsft") {
@@ -140,14 +147,7 @@ $x = Math::BigInt->new(1200); $y = $class->new($x);
 ok ($y,1200); ok ($x,1200);
 
 ###############################################################################
-# fdiv() in list context
-
-$x = $class->bzero(); ($x,$y) = $x->fdiv(0);
-ok ($x,'NaN'); ok ($y,'NaN');
-
-# fdiv() in list context
-$x = $class->bzero(); ($x,$y) = $x->fdiv(1);
-ok ($x,0); ok ($y,0);
+# zero,inf,one,nan
 
 $x = $class->new(2); $x->fzero(); ok_undef ($x->{_a}); ok_undef ($x->{_p});
 $x = $class->new(2); $x->finf();  ok_undef ($x->{_a}); ok_undef ($x->{_p});
@@ -168,7 +168,7 @@ $x = $class->new(12); $class->precision(0); $x->fsqrt(); ok ($x,'3');
 $class->precision(-3); $x = $class->new(12); $x->fsqrt(); ok ($x,'3.464');
 
 # A and P set => NaN
-$class->accuracy(4); $x = $class->new(12); $x->fsqrt(3); ok ($x,'NaN');
+${${class}.'::accuracy'} = 4; $x = $class->new(12); $x->fsqrt(3); ok ($x,'NaN');
 # supplied arg overrides set global
 $class->precision(undef); $x = $class->new(12); $x->fsqrt(3); ok ($x,'3.46');
 
@@ -188,19 +188,31 @@ sub ok_undef
   }
 
 __DATA__
-#&flog
-#$div_scale = 14;
-#10:0:2.30258509299405
+$div_scale = 40;
+&flog
+0:NaN
+-1:NaN
+-2:NaN
+1:0
+# this is too slow for the testsuite
+#2.718281828:0.9999999998311266953289851340574956564911
+#$div_scale = 20;
+#2.718281828:0.99999999983112669533
+1:0
+# too slow, too (or hangs?)
+#123:4.8112184355
+# $div_scale = 14;
+#10:0:2.302585092994
 #1000:0:6.90775527898214
 #100:0:4.60517018598809
 #2:0:0.693147180559945
 #3.1415:0:1.14470039286086
 #12345:0:9.42100640177928
 #0.001:0:-6.90775527898214
-## reset for further tests
-#$div_scale = 40;
+# reset for further tests
+$div_scale = 40;
 &frsft
-#NaNfrsft:NaN
+NaNfrsft:2:NaN
 0:2:0
 1:1:0.5
 2:1:1
@@ -208,7 +220,7 @@ __DATA__
 123:1:61.5
 32:3:4
 &flsft
-#NaNflsft:NaN
+NaNflsft:0:NaN
 2:1:4
 4:3:32
 5:3:40
@@ -880,6 +892,11 @@ NaNmul:-inf:NaN
 +99999999999:+9:899999999991
 6:120:720
 10:10000:100000
+&fdiv-list
+0:0:NaN,NaN
+0:1:0,0
+9:4:2.25,1
+9:5:1.8,4
 &fdiv
 $div_scale = 40; $round_mode = 'even'
 abc:abc:NaN
@@ -975,10 +992,10 @@ inf:-5:0
 -inf:-5:0
 5:5:0
 -5:-5:0
-inf:inf:0
--inf:-inf:0
--inf:inf:0
-inf:-inf:0
+inf:inf:NaN
+-inf:-inf:NaN
+-inf:inf:NaN
+inf:-inf:NaN
 8:0:8
 inf:0:inf
 # exceptions to reminder rule
@@ -1041,6 +1058,19 @@ abc:1:abc:NaN
 1230:2.5:0
 123.4:2.5:0.9
 123e1:25:5
+&ffac
+Nanfac:NaN
+-1:NaN
+0:1
+1:1
+2:2
+3:6
+4:24
+5:120
+6:720
+10:3628800
+11:39916800
+12:479001600
 &fsqrt
 +0:0
 -1:NaN
@@ -1062,6 +1092,7 @@ nanfsqrt:NaN
 # sqrt(1.44) = 1.2, sqrt(e10) = e5 => 12e4
 1.44E10:120000
 2e10:141421.356237309504880168872420969807857
+144e20:120000000000
 # proved to be an endless loop under 7-9
 12:3.464101615137754587054892683011744733886
 &is_nan
@@ -1097,6 +1128,18 @@ abc:0
 123.45:0
 -123.45:0
 2:0
+&is_int
+NaNis_int:0
+0:1
+1:1
+2:1
+-2:1
+-1:1
+-inf:0
++inf:0
+123.4567:0
+-0.1:0
+-0.002:0
 &is_even
 abc:0
 0:1
@@ -1111,6 +1154,11 @@ abc:0
 -inf:0
 123.456:0
 -123.456:0
+0.01:0
+-0.01:0
+120:1
+1200:1
+-1200:1
 &is_positive
 0:1
 1:1
diff --git a/lib/Math/BigInt/t/bigfltpm.t b/lib/Math/BigInt/t/bigfltpm.t
index 2c98122..0ed5c4a 100755
--- a/lib/Math/BigInt/t/bigfltpm.t
+++ b/lib/Math/BigInt/t/bigfltpm.t
@@ -26,13 +26,14 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 1528;
+  plan tests => 1585;
   }
 
 use Math::BigInt;
 use Math::BigFloat;
 
-use vars qw ($class $try $x $y $f @args $ans $ans1 $ans1_str $setup);
+use vars qw ($class $try $x $y $f @args $ans $ans1 $ans1_str $setup $CL);
 $class = "Math::BigFloat";
+$CL = "Math::BigInt::Calc";
    
 require 'bigfltpm.inc';	# all tests here for sharing
diff --git a/lib/Math/BigInt/t/bigintc.t b/lib/Math/BigInt/t/bigintc.t
index 220ce30..26530ca 100644
--- a/lib/Math/BigInt/t/bigintc.t
+++ b/lib/Math/BigInt/t/bigintc.t
@@ -16,7 +16,7 @@ BEGIN
   {
   my $additional = 0;
   $additional = 27 if $Math::BigInt::Calc::VERSION > 0.18;
-  plan tests => 71 + $additional;
+  plan tests => 80 + $additional;
   }
 
 # testing of Math::BigInt::Calc, primarily for interface/api and not for the
@@ -124,6 +124,19 @@ $x = $C->_new(\"123"); $y = $C->_new(\"1111");
 # _num
 $x = $C->_new(\"12345"); $x = $C->_num($x); ok (ref($x)||'',''); ok ($x,12345);
 
+# _sqrt
+$x = $C->_new(\"144"); ok (${$C->_str($C->_sqrt($x))},'12');
+
+# _fac
+$x = $C->_new(\"0"); ok (${$C->_str($C->_fac($x))},'1');
+$x = $C->_new(\"1"); ok (${$C->_str($C->_fac($x))},'1');
+$x = $C->_new(\"2"); ok (${$C->_str($C->_fac($x))},'2');
+$x = $C->_new(\"3"); ok (${$C->_str($C->_fac($x))},'6');
+$x = $C->_new(\"4"); ok (${$C->_str($C->_fac($x))},'24');
+$x = $C->_new(\"5"); ok (${$C->_str($C->_fac($x))},'120');
+$x = $C->_new(\"10"); ok (${$C->_str($C->_fac($x))},'3628800');
+$x = $C->_new(\"11"); ok (${$C->_str($C->_fac($x))},'39916800');
+
 # _inc
 $x = $C->_new(\"1000"); $C->_inc($x); ok (${$C->_str($x)},'1001');
 $C->_dec($x); ok (${$C->_str($x)},'1000');
diff --git a/lib/Math/BigInt/t/bigintpm.inc b/lib/Math/BigInt/t/bigintpm.inc
index 5d8bddb..137ead4 100644
--- a/lib/Math/BigInt/t/bigintpm.inc
+++ b/lib/Math/BigInt/t/bigintpm.inc
@@ -34,9 +34,9 @@ sub _swap
 ##############################################################################
 package main;
 
-my $CALC = $class->_core_lib(); ok ($CALC,$CL);
+my $CALC = $class->config()->{lib}; ok ($CALC,$CL);
 
-my ($f,$z,$a,$exp,@a,$m,$e,$round_mode);
+my ($f,$z,$a,$exp,@a,$m,$e,$round_mode,$expected_class);
 
 while (<DATA>) 
   {
@@ -52,12 +52,17 @@ while (<DATA>)
     }
 
   @args = split(/:/,$_,99); $ans = pop(@args);
+  $expected_class = $class;
+  if ($ans =~ /(.*?)=(.*)/)
+    {
+    $expected_class = $2; $ans = $1;
+    }
   $try = "\$x = $class->new(\"$args[0]\");";
   if ($f eq "bnorm")
     {
     $try = "\$x = $class->bnorm(\"$args[0]\");";
   # some is_xxx tests
-   } elsif ($f =~ /^is_(zero|one|odd|even|negative|positive|nan)$/) {
+   } elsif ($f =~ /^is_(zero|one|odd|even|negative|positive|nan|int)$/) {
     $try .= "\$x->$f();";
    } elsif ($f eq "as_hex") {
     $try .= '$x->as_hex();';
@@ -70,7 +75,7 @@ while (<DATA>)
    } elsif ($f eq "bone") {
     $try .= "\$x->bone('$args[1]');";
    # some unary ops
-   } elsif ($f =~ /^b(nan|floor|ceil|sstr|neg|abs|inc|dec|not|sqrt)$/) {
+   } elsif ($f =~ /^b(nan|floor|ceil|sstr|neg|abs|inc|dec|not|sqrt|fac)$/) {
     $try .= "\$x->$f();";
    } elsif ($f eq "length") {
     $try .= '$x->length();';
@@ -177,6 +182,7 @@ while (<DATA>)
     {
     # print "try: $try ans: $ans1 $ans\n";
     print "# Tried: '$try'\n" if !ok ($ans1, $ans);
+    ok (ref($ans),$expected_class) if $expected_class ne $class;
     }
   # check internal state of number objects
   is_valid($ans1,$f) if ref $ans1; 
@@ -562,6 +568,13 @@ NaNneg:0
 +inf:1
 -inf:0
 NaNneg:0
+&is_int
+-inf:0
++inf:0
+NaNis_int:0
+1:1
+0:1
+123e12:1
 &is_odd
 abc:0
 0:0
@@ -572,6 +585,8 @@ abc:0
 10000001:1
 10000002:0
 2:0
+120:0
+121:1
 &is_even
 abc:0
 0:1
@@ -582,6 +597,8 @@ abc:0
 10000001:0
 10000002:1
 2:1
+120:1
+121:0
 &bacmp
 +0:-0:0
 +0:+1:-1
@@ -836,6 +853,10 @@ abc:abc:NaN
 +12:2:10:1200
 +1234:-3:10:NaN
 1234567890123:12:10:1234567890123000000000000
+-3:1:2:-6
+-5:1:2:-10
+-2:1:2:-4
+-102533203:1:2:-205066406
 &brsft
 abc:abc:NaN
 +8:+2:2
@@ -854,6 +875,27 @@ abc:abc:NaN
 1230000000000:10:10:123
 09876123456789067890:12:10:9876123
 1234561234567890123:13:10:123456
+820265627:1:2:410132813
+# test shifting negative numbers in base 2
+-15:1:2:-8
+-14:1:2:-7
+-13:1:2:-7
+-12:1:2:-6
+-11:1:2:-6
+-10:1:2:-5
+-9:1:2:-5
+-8:1:2:-4
+-7:1:2:-4
+-6:1:2:-3
+-5:1:2:-3
+-4:1:2:-2
+-3:1:2:-2
+-2:1:2:-1
+-1:1:2:-1
+-1640531254:2:2:-410132814
+-1640531254:1:2:-820265627
+-820265627:1:2:-410132814
+-205066405:1:2:-102533203
 &bsstr
 1e+34:1e+34
 123.456E3:123456e+0
@@ -940,8 +982,8 @@ abc:NaN
 abc:abc:NaN
 abc:0:NaN
 +0:abc:NaN
-+inf:-inf:0
--inf:+inf:0
++inf:-inf:NaN
+-inf:+inf:NaN
 +inf:+inf:inf
 -inf:-inf:-inf
 baddNaN:+inf:NaN
@@ -988,8 +1030,8 @@ abc:+0:NaN
 +0:abc:NaN
 +inf:-inf:inf
 -inf:+inf:-inf
-+inf:+inf:0
--inf:-inf:0
++inf:+inf:NaN
+-inf:-inf:NaN
 +0:+0:0
 +1:+0:1
 +0:+1:-1
@@ -1091,6 +1133,8 @@ NaNmul:-inf:NaN
 4095:-4095:-1,0
 -4095:4095:-1,0
 123:2:61,1
+9:5:1,4
+9:4:2,1
 # inf handling and general remainder
 5:8:0,5
 0:8:0,0
@@ -1110,10 +1154,10 @@ inf:-5:-inf,0
 -inf:-5:inf,0
 5:5:1,0
 -5:-5:1,0
-inf:inf:1,0
--inf:-inf:1,0
--inf:inf:-1,0
-inf:-inf:-1,0
+inf:inf:NaN,NaN
+-inf:-inf:NaN,NaN
+-inf:inf:NaN,NaN
+inf:-inf:NaN,NaN
 8:0:inf,8
 inf:0:inf,inf
 # exceptions to reminder rule
@@ -1138,10 +1182,10 @@ inf:-5:-inf
 -inf:-5:inf
 5:5:1
 -5:-5:1
-inf:inf:1
--inf:-inf:1
--inf:inf:-1
-inf:-inf:-1
+inf:inf:NaN
+-inf:-inf:NaN
+-inf:inf:NaN
+inf:-inf:NaN
 8:0:inf
 inf:0:inf
 -8:0:-inf
@@ -1213,10 +1257,10 @@ inf:-5:0
 -inf:-5:0
 5:5:0
 -5:-5:0
-inf:inf:0
--inf:-inf:0
--inf:inf:0
-inf:-inf:0
+inf:inf:NaN
+-inf:-inf:NaN
+-inf:inf:NaN
+inf:-inf:NaN
 8:0:8
 inf:0:inf
 # exceptions to reminder rule
@@ -1273,6 +1317,7 @@ abc:1:abc:NaN
 4095:4095:0
 100041000510123:3:0
 152403346:12345:4321
+9:5:4
 &bgcd
 abc:abc:NaN
 abc:+0:NaN
@@ -1483,6 +1528,21 @@ abc:NaN,NaN
 0:0,1
 +inf:inf,inf
 -inf:-inf,inf
+&bfac
+-1:NaN
+NaNfac:NaN
++inf:NaN
+-inf:NaN
+0:1
+1:1
+2:2
+3:6
+4:24
+5:120
+6:720
+10:3628800
+11:39916800
+12:479001600
 &bpow
 abc:12:NaN
 12:abc:NaN
diff --git a/lib/Math/BigInt/t/bigintpm.t b/lib/Math/BigInt/t/bigintpm.t
index 913c19b..f4b2a79 100755
--- a/lib/Math/BigInt/t/bigintpm.t
+++ b/lib/Math/BigInt/t/bigintpm.t
@@ -10,7 +10,7 @@ BEGIN
   my $location = $0; $location =~ s/bigintpm.t//;
   unshift @INC, $location; # to locate the testing files
   chdir 't' if -d 't';
-  plan tests => 2005;
+  plan tests => 2095;
   }
 
 use Math::BigInt;
diff --git a/lib/Math/BigInt/t/calling.t b/lib/Math/BigInt/t/calling.t
index 800b879..ca78fe9 100644
--- a/lib/Math/BigInt/t/calling.t
+++ b/lib/Math/BigInt/t/calling.t
@@ -97,7 +97,7 @@ ok_undef ( $_ );               # should result in error!
 
 # test whether fallback to calc works
 $try = "use $class ($version,'lib','foo, bar , ');";
-$try .= "$class\->_core_lib();";
+$try .= "$class\->config()->{lib};";
 $ans = eval $try;
 ok ( $ans, "Math::BigInt::Calc");
 
diff --git a/lib/Math/BigInt/t/config.t b/lib/Math/BigInt/t/config.t
new file mode 100644
index 0000000..5c660a7
--- /dev/null
+++ b/lib/Math/BigInt/t/config.t
@@ -0,0 +1,36 @@
+#!/usr/bin/perl -w
+
+use strict;
+use Test;
+
+BEGIN
+  {
+  $| = 1;
+  chdir 't' if -d 't';
+  unshift @INC, '../lib'; # for running manually
+  plan tests => 10;
+  } 
+
+# test whether Math::BigInt constant works
+
+use Math::BigInt;
+
+ok (Math::BigInt->can('config'));
+
+my $cfg = Math::BigInt->config();
+
+ok (ref($cfg),'HASH');
+
+ok ($cfg->{lib},'Math::BigInt::Calc');
+ok ($cfg->{lib_version},'0.22');
+ok ($cfg->{class},'Math::BigInt');
+ok ($cfg->{upgrade}||'','');
+ok ($cfg->{div_scale},40);
+
+ok ($cfg->{precision}||0,0);	# should test for undef
+ok ($cfg->{accuracy}||0,0);
+
+ok ($cfg->{round_mode},'even');
+
+# all tests done
+
diff --git a/lib/Math/BigInt/t/constant.t b/lib/Math/BigInt/t/constant.t
new file mode 100644
index 0000000..ef3e223
--- /dev/null
+++ b/lib/Math/BigInt/t/constant.t
@@ -0,0 +1,33 @@
+#!/usr/bin/perl -w
+
+use strict;
+use Test;
+
+BEGIN
+  {
+  $| = 1;
+  chdir 't' if -d 't';
+  unshift @INC, '../lib'; # for running manually
+  plan tests => 5;
+  } 
+
+use Math::BigInt ':constant';
+
+ok (2 ** 255,'57896044618658097711785492504343953926634992332820282019728792003956564819968');
+
+use Math::BigFloat ':constant';
+ok (1.0 / 3.0, '0.3333333333333333333333333333333333333333');
+
+# stress-test Math::BigFloat->import()
+
+Math::BigFloat->import( qw/:constant/ );
+ok (1,1);
+
+Math::BigFloat->import( qw/:constant upgrade Math::BigRat/ );
+ok (1,1);
+
+Math::BigFloat->import( qw/upgrade Math::BigRat :constant/ );
+ok (1,1);
+
+# all tests done
+
diff --git a/lib/Math/BigInt/t/inf_nan.t b/lib/Math/BigInt/t/inf_nan.t
new file mode 100644
index 0000000..38ebe03
--- /dev/null
+++ b/lib/Math/BigInt/t/inf_nan.t
@@ -0,0 +1,255 @@
+#!/usr/bin/perl -w
+
+use Test;
+use strict;
+
+BEGIN
+  {
+  $| = 1;
+  plan tests => 7*6*4;
+  chdir 't' if -d 't';
+  unshift @INC, '../lib';
+  }
+
+use Math::BigInt;
+
+my (@args,$x,$y,$z);
+
+# +
+foreach (qw/
+  -inf:-inf:-inf
+  -1:-inf:-inf
+  -0:-inf:-inf
+  0:-inf:-inf
+  1:-inf:-inf
+  inf:-inf:NaN
+  NaN:-inf:NaN
+
+  -inf:-1:-inf
+  -1:-1:-2
+  -0:-1:-1
+  0:-1:-1
+  1:-1:0
+  inf:-1:inf
+  NaN:-1:NaN
+
+  -inf:0:-inf
+  -1:0:-1
+  -0:0:0
+  0:0:0
+  1:0:1
+  inf:0:inf
+  NaN:0:NaN
+
+  -inf:1:-inf
+  -1:1:0
+  -0:1:1
+  0:1:1
+  1:1:2
+  inf:1:inf
+  NaN:1:NaN
+
+  -inf:inf:NaN
+  -1:inf:inf
+  -0:inf:inf
+  0:inf:inf
+  1:inf:inf
+  inf:inf:inf
+  NaN:inf:NaN
+
+  -inf:NaN:NaN
+  -1:NaN:NaN
+  -0:NaN:NaN
+  0:NaN:NaN
+  1:NaN:NaN
+  inf:NaN:NaN
+  NaN:NaN:NaN
+  /)
+  {
+  @args = split /:/,$_;
+  $x = Math::BigInt->new($args[0]);
+  $y = Math::BigInt->new($args[1]);
+  $args[2] = '0' if $args[2] eq '-0';	# BigInt hasn't got -0
+  print "# $args[0] + $args[1] should be $args[2] but is ",$x->bstr(),"\n"
+    if !ok ($x->badd($y)->bstr(),$args[2]);
+  }
+
+# -
+foreach (qw/
+  -inf:-inf:NaN
+  -1:-inf:inf
+  -0:-inf:inf
+  0:-inf:inf
+  1:-inf:inf
+  inf:-inf:inf
+  NaN:-inf:NaN
+
+  -inf:-1:-inf
+  -1:-1:0
+  -0:-1:1
+  0:-1:1
+  1:-1:2
+  inf:-1:inf
+  NaN:-1:NaN
+
+  -inf:0:-inf
+  -1:0:-1
+  -0:0:-0
+  0:0:0
+  1:0:1
+  inf:0:inf
+  NaN:0:NaN
+
+  -inf:1:-inf
+  -1:1:-2
+  -0:1:-1
+  0:1:-1
+  1:1:0
+  inf:1:inf
+  NaN:1:NaN
+
+  -inf:inf:-inf
+  -1:inf:-inf
+  -0:inf:-inf
+  0:inf:-inf
+  1:inf:-inf
+  inf:inf:NaN
+  NaN:inf:NaN
+
+  -inf:NaN:NaN
+  -1:NaN:NaN
+  -0:NaN:NaN
+  0:NaN:NaN
+  1:NaN:NaN
+  inf:NaN:NaN
+  NaN:NaN:NaN
+  /)
+  {
+  @args = split /:/,$_;
+  $x = Math::BigInt->new($args[0]);
+  $y = Math::BigInt->new($args[1]);
+  $args[2] = '0' if $args[2] eq '-0';	# BigInt hasn't got -0
+  print "# $args[0] - $args[1] should be $args[2] but is $x\n"
+   if !ok ($x->bsub($y)->bstr(),$args[2]);
+  }
+
+# *
+foreach (qw/
+  -inf:-inf:inf
+  -1:-inf:inf
+  -0:-inf:NaN
+  0:-inf:NaN
+  1:-inf:-inf
+  inf:-inf:-inf
+  NaN:-inf:NaN
+
+  -inf:-1:inf
+  -1:-1:1
+  -0:-1:0
+  0:-1:-0
+  1:-1:-1
+  inf:-1:-inf
+  NaN:-1:NaN
+
+  -inf:0:NaN
+  -1:0:-0
+  -0:0:-0
+  0:0:0
+  1:0:0
+  inf:0:NaN
+  NaN:0:NaN
+
+  -inf:1:-inf
+  -1:1:-1
+  -0:1:-0
+  0:1:0
+  1:1:1
+  inf:1:inf
+  NaN:1:NaN
+
+  -inf:inf:-inf
+  -1:inf:-inf
+  -0:inf:NaN
+  0:inf:NaN
+  1:inf:inf
+  inf:inf:inf
+  NaN:inf:NaN
+
+  -inf:NaN:NaN
+  -1:NaN:NaN
+  -0:NaN:NaN
+  0:NaN:NaN
+  1:NaN:NaN
+  inf:NaN:NaN
+  NaN:NaN:NaN
+  /)
+  {
+  @args = split /:/,$_;
+  $x = Math::BigInt->new($args[0]);
+  $y = Math::BigInt->new($args[1]);
+  $args[2] = '0' if $args[2] eq '-0';	# BigInt hasn't got -0
+  print "# $args[0] * $args[1] should be $args[2] but is $x\n"
+   if !ok ($x->bmul($y)->bstr(),$args[2]);
+  }
+
+# /
+foreach (qw/
+  -inf:-inf:NaN
+  -1:-inf:0
+  -0:-inf:0
+  0:-inf:-0
+  1:-inf:-0
+  inf:-inf:NaN
+  NaN:-inf:NaN
+
+  -inf:-1:inf
+  -1:-1:1
+  -0:-1:0
+  0:-1:-0
+  1:-1:-1
+  inf:-1:-inf
+  NaN:-1:NaN
+
+  -inf:0:-inf
+  -1:0:-inf
+  -0:0:NaN
+  0:0:NaN
+  1:0:inf
+  inf:0:inf
+  NaN:0:NaN
+
+  -inf:1:-inf
+  -1:1:-1
+  -0:1:-0
+  0:1:0
+  1:1:1
+  inf:1:inf
+  NaN:1:NaN
+
+  -inf:inf:NaN
+  -1:inf:-0
+  -0:inf:-0
+  0:inf:0
+  1:inf:0
+  inf:inf:NaN
+  NaN:inf:NaN
+
+  -inf:NaN:NaN
+  -1:NaN:NaN
+  -0:NaN:NaN
+  0:NaN:NaN
+  1:NaN:NaN
+  inf:NaN:NaN
+  NaN:NaN:NaN
+  /)
+  {
+  @args = split /:/,$_;
+  $x = Math::BigInt->new($args[0]);
+  $y = Math::BigInt->new($args[1]);
+  $args[2] = '0' if $args[2] eq '-0';	# BigInt hasn't got -0
+  print "# $args[0] / $args[1] should be $args[2] but is $x\n"
+   if !ok ($x->bdiv($y)->bstr(),$args[2]);
+
+  }
+
+
diff --git a/lib/Math/BigInt/t/mbimbf.inc b/lib/Math/BigInt/t/mbimbf.inc
index bdb1271..f432918 100644
--- a/lib/Math/BigInt/t/mbimbf.inc
+++ b/lib/Math/BigInt/t/mbimbf.inc
@@ -149,7 +149,7 @@ ok ($x->copy()->round(5),'123.46');
 ok ($x->copy()->round(4),'123.5');
 ok ($x->copy()->round(5,2),'NaN');
 ok ($x->copy()->round(undef,-2),'123.46');
-ok ($x->copy()->round(undef,2),100);
+ok ($x->copy()->round(undef,2),120);
 
 $x = $mbi->new('123');
 ok ($x->round(5,2),'NaN');
@@ -265,7 +265,9 @@ $y = $mbi->new(12345);
 $z = $u->copy()->bmul($y,2,undef,'odd'); ok ($z,31000);
 $z = $u->copy()->bmul($y,3,undef,'odd'); ok ($z,30900);
 $z = $u->copy()->bmul($y,undef,0,'odd'); ok ($z,30863);
-$z = $u->copy()->bmul($y,undef,1,'odd'); ok ($z,30860);
+$z = $u->copy()->bmul($y,undef,1,'odd'); ok ($z,30863);
+$z = $u->copy()->bmul($y,undef,2,'odd'); ok ($z,30860);
+$z = $u->copy()->bmul($y,undef,3,'odd'); ok ($z,30900);
 $z = $u->copy()->bmul($y,undef,-1,'odd'); ok ($z,30862.5);
 
 # breakage:
@@ -392,8 +394,12 @@ $x = $mbi->new(12345); $x->{_a} = 5;
 $x->bround(6);                  # must be no-op
 ok ($x,'12345');
 
-$x = $mbf->new('0.0061'); $x->bfround(-2);
-ok ($x,'0.01');
+$x = $mbf->new('0.0061'); $x->bfround(-2); ok ($x,'0.01');
+$x = $mbf->new('0.004'); $x->bfround(-2);  ok ($x,'0.00');
+$x = $mbf->new('0.005'); $x->bfround(-2);  ok ($x,'0.00');
+
+$x = $mbf->new('12345'); $x->bfround(2); ok ($x,'12340');
+$x = $mbf->new('12340'); $x->bfround(2); ok ($x,'12340');
 
 # MBI::bfround should clear A for negative P
 $x = $mbi->new('1234'); $x->accuracy(3); $x->bfround(-2);
@@ -572,11 +578,16 @@ foreach (qw/new bsqrt/)
   print "# Tried: '$try'\n" if !ok ($rc, 'NaN');
   }
 
+# see if $x->bsub(0) really rounds
+$x = $mbi->new(123); $mbi->accuracy(2); $x->bsub(0);
+ok ($x,120);
+$mbi->accuracy(undef);
+
 ###############################################################################
 # test whether shortcuts returning zero/one preserve A and P
 
 my ($ans1,$f,$a,$p,$xp,$yp,$xa,$ya,$try,$ans,@args);
-my $CALC = Math::BigInt::_core_lib();
+my $CALC = Math::BigInt->config()->{lib};
 while (<DATA>)
   {
   chop;
@@ -619,7 +630,7 @@ while (<DATA>)
   $a = $xa || $ya; $p = $xp || $yp;
 
   # print "Check a=$a p=$p\n";
-  print "# Tried: '$try'\n";
+  # print "# Tried: '$try'\n";
   ok ($x->{_a}, $a) && ok_undef ($x->{_p}) if $a ne ''; 
   ok ($x->{_p}, $p) && ok_undef ($x->{_a}) if $p ne ''; 
   }
@@ -671,7 +682,6 @@ sub is_valid
 # the A or P of the result is calculated automatically
 __DATA__
 &badd
-# bsub uses badd anyway, so it should be right
 123,,:123,,:246
 123,3,:0,,:123
 123,,-3:0,,:123
diff --git a/lib/Math/BigInt/t/mbimbf.t b/lib/Math/BigInt/t/mbimbf.t
index af3e4cf..736006c 100644
--- a/lib/Math/BigInt/t/mbimbf.t
+++ b/lib/Math/BigInt/t/mbimbf.t
@@ -31,12 +31,12 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 428 
-    + 8;		# own test
+  plan tests => 435 
+    + 16;		# own tests
   }
 
-use Math::BigInt 1.49;
-use Math::BigFloat 1.26;
+use Math::BigInt 1.50;
+use Math::BigFloat 1.27;
 
 use vars qw/$mbi $mbf/;
 
@@ -70,3 +70,11 @@ ok ($@ =~ /^Unknown round mode huhmbf at/);
 $mbi->round_mode('odd'); ok ($Math::BigInt::rnd_mode,'odd');
 $mbf->round_mode('odd'); ok ($Math::BigInt::rnd_mode,'odd');
 
+foreach my $class (qw/Math::BigInt Math::BigFloat/)
+  {
+  ok ($class->accuracy(5),5);		# set A
+  ok_undef ($class->precision());	# and now P must be cleared
+  ok ($class->precision(5),5);		# set P
+  ok_undef ($class->accuracy());	# and now A must be cleared
+  }
+
diff --git a/lib/Math/BigInt/t/require.t b/lib/Math/BigInt/t/require.t
index f98dbeb..de109f1 100644
--- a/lib/Math/BigInt/t/require.t
+++ b/lib/Math/BigInt/t/require.t
@@ -23,5 +23,3 @@ ok ($x||'undef',2);
 
 # all tests done
 
-1;
-
diff --git a/lib/Math/BigInt/t/sub_mbf.t b/lib/Math/BigInt/t/sub_mbf.t
index 92d04e8..417bbce 100755
--- a/lib/Math/BigInt/t/sub_mbf.t
+++ b/lib/Math/BigInt/t/sub_mbf.t
@@ -26,14 +26,15 @@ BEGIN
     }
   print "# INC = @INC\n"; 
   
-  plan tests => 1528
+  plan tests => 1585
     + 4;	# + 4 own tests
   }
 
 use Math::BigFloat::Subclass;
 
-use vars qw ($class $try $x $y $f @args $ans $ans1 $ans1_str $setup);
+use vars qw ($class $try $x $y $f @args $ans $ans1 $ans1_str $setup $CL);
 $class = "Math::BigFloat::Subclass";
+$CL = "Math::BigInt::Calc";
 
 require 'bigfltpm.inc';	# perform same tests as bigfltpm
 
diff --git a/lib/Math/BigInt/t/sub_mbi.t b/lib/Math/BigInt/t/sub_mbi.t
index eeedafe..89b7d9a 100755
--- a/lib/Math/BigInt/t/sub_mbi.t
+++ b/lib/Math/BigInt/t/sub_mbi.t
@@ -26,7 +26,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 2005
+  plan tests => 2095
     + 4;	# +4 own tests
   }
 
diff --git a/lib/Math/BigInt/t/sub_mif.t b/lib/Math/BigInt/t/sub_mif.t
index 01b87db..5abd6ae 100644
--- a/lib/Math/BigInt/t/sub_mif.t
+++ b/lib/Math/BigInt/t/sub_mif.t
@@ -13,9 +13,9 @@ BEGIN
   my $location = $0; $location =~ s/sub_mif.t//i;
   if ($ENV{PERL_CORE})
     {
-    @INC = qw(../t/lib);               # testing with the core distribution
+    @INC = qw(../t/lib); 		# testing with the core distribution
     }
-  unshift @INC, '../lib';      # for testing manually
+  unshift @INC, '../lib';	# for testing manually
   if (-d 't')
     {
     chdir 't';
@@ -27,8 +27,8 @@ BEGIN
     unshift @INC, $location;
     }
   print "# INC = @INC\n";
-  
-  plan tests => 428;
+
+  plan tests => 435;
   }
 
 use Math::BigInt::Subclass;
diff --git a/lib/Math/BigInt/t/upgrade.inc b/lib/Math/BigInt/t/upgrade.inc
new file mode 100644
index 0000000..6dcaa75
--- /dev/null
+++ b/lib/Math/BigInt/t/upgrade.inc
@@ -0,0 +1,1463 @@
+#include this file into another for subclass testing
+
+# This file is nearly identical to bigintpm.t, except that certain results
+# are _requird_ to be different due to "upgrading" or "promoting" to BigFloat.
+# The reverse is not true, any unmarked results can be either BigInt or
+# BigFloat, depending on how good the internal optimization is.
+
+# Plaese note that the testcount goes up by two for each extra result marked
+# with ^, since then we test whether it has the proper class and that it left
+# the upgrade variable alone.
+
+my $version = ${"$class\::VERSION"};
+
+##############################################################################
+# for testing inheritance of _swap
+
+package Math::Foo;
+
+use Math::BigInt lib => $main::CL;
+use vars qw/@ISA/;
+@ISA = (qw/Math::BigInt/);
+
+use overload
+# customized overload for sub, since original does not use swap there
+'-'     =>      sub { my @a = ref($_[0])->_swap(@_);
+                   $a[0]->bsub($a[1])};
+
+sub _swap
+  {
+  # a fake _swap, which reverses the params
+  my $self = shift;                     # for override in subclass
+  if ($_[2])
+    {
+    my $c = ref ($_[0] ) || 'Math::Foo';
+    return ( $_[0]->copy(), $_[1] );
+    }
+  else
+    {
+    return ( Math::Foo->new($_[1]), $_[0] );
+    }
+  }
+
+##############################################################################
+package main;
+
+my $CALC = $class->config()->{lib}; ok ($CALC,$CL);
+
+my ($f,$z,$a,$exp,@a,$m,$e,$round_mode,$expected_class);
+
+while (<DATA>) 
+  {
+  chop;
+  next if /^#/;	# skip comments
+  if (s/^&//) 
+    {
+    $f = $_; next;
+    }
+  elsif (/^\$/) 
+    {
+    $round_mode = $_; $round_mode =~ s/^\$/$class\->/; next;
+    }
+
+  @args = split(/:/,$_,99); $ans = pop(@args);
+  $expected_class = $class;
+  if ($ans =~ /\^$/)
+    {
+    $expected_class = $ECL; $ans =~ s/\^$//;
+    }
+  $try = "\$x = $class->new(\"$args[0]\");";
+  if ($f eq "bnorm")
+    {
+    $try = "\$x = $class->bnorm(\"$args[0]\");";
+  # some is_xxx tests
+   } elsif ($f =~ /^is_(zero|one|odd|even|negative|positive|nan|int)$/) {
+    $try .= "\$x->$f();";
+   } elsif ($f eq "as_hex") {
+    $try .= '$x->as_hex();';
+   } elsif ($f eq "as_bin") {
+    $try .= '$x->as_bin();';
+   } elsif ($f eq "is_inf") {
+    $try .= "\$x->is_inf('$args[1]');";
+   } elsif ($f eq "binf") {
+    $try .= "\$x->binf('$args[1]');";
+   } elsif ($f eq "bone") {
+    $try .= "\$x->bone('$args[1]');";
+   # some unary ops
+   } elsif ($f =~ /^b(nan|floor|ceil|sstr|neg|abs|inc|dec|not|sqrt|fac)$/) {
+    $try .= "\$x->$f();";
+   } elsif ($f eq "length") {
+    $try .= '$x->length();';
+   } elsif ($f eq "exponent"){
+    # ->bstr() to see if an object is returned
+    $try .= '$x = $x->exponent()->bstr();';
+   } elsif ($f eq "mantissa"){
+    # ->bstr() to see if an object is returned
+    $try .= '$x = $x->mantissa()->bstr();';
+   } elsif ($f eq "parts"){
+    $try .= '($m,$e) = $x->parts();'; 
+    # ->bstr() to see if an object is returned
+    $try .= '$m = $m->bstr(); $m = "NaN" if !defined $m;';
+    $try .= '$e = $e->bstr(); $e = "NaN" if !defined $e;';
+    $try .= '"$m,$e";';
+   } else {
+    $try .= "\$y = $class->new('$args[1]');";
+    if ($f eq "bcmp")
+      {
+      $try .= '$x <=> $y;';
+      } elsif ($f eq "bround") {
+      $try .= "$round_mode; \$x->bround(\$y);";
+      } elsif ($f eq "bacmp"){
+      $try .= '$x->bacmp($y);';
+      } elsif ($f eq "badd"){
+      $try .= '$x + $y;';
+      } elsif ($f eq "bsub"){
+      $try .= '$x - $y;';
+      } elsif ($f eq "bmul"){
+      $try .= '$x * $y;';
+      } elsif ($f eq "bdiv"){
+      $try .= '$x / $y;';
+      } elsif ($f eq "bdiv-list"){
+      $try .= 'join (",",$x->bdiv($y));';
+      # overload via x=
+      } elsif ($f =~ /^.=$/){
+      $try .= "\$x $f \$y;";
+      # overload via x
+      } elsif ($f =~ /^.$/){
+      $try .= "\$x $f \$y;";
+      } elsif ($f eq "bmod"){
+      $try .= '$x % $y;';
+      } elsif ($f eq "bgcd")
+        {
+        if (defined $args[2])
+          {
+          $try .= " \$z = $class->new('$args[2]'); ";
+          }
+        $try .= "$class\::bgcd(\$x, \$y";
+        $try .= ", \$z" if (defined $args[2]);
+        $try .= " );";
+        }
+      elsif ($f eq "blcm")
+        {
+        if (defined $args[2])
+          {
+          $try .= " \$z = $class->new('$args[2]'); ";
+          }
+        $try .= "$class\::blcm(\$x, \$y";
+        $try .= ", \$z" if (defined $args[2]);
+        $try .= " );";
+      }elsif ($f eq "blsft"){
+        if (defined $args[2])
+          {
+          $try .= "\$x->blsft(\$y,$args[2]);";
+          }
+        else
+          {
+          $try .= "\$x << \$y;";
+          }
+      }elsif ($f eq "brsft"){
+        if (defined $args[2])
+          {
+          $try .= "\$x->brsft(\$y,$args[2]);";
+          }
+        else
+          {
+          $try .= "\$x >> \$y;";
+          }
+      }elsif ($f eq "band"){
+        $try .= "\$x & \$y;";
+      }elsif ($f eq "bior"){
+        $try .= "\$x | \$y;";
+      }elsif ($f eq "bxor"){
+        $try .= "\$x ^ \$y;";
+      }elsif ($f eq "bpow"){
+        $try .= "\$x ** \$y;";
+      }elsif ($f eq "digit"){
+        $try = "\$x = $class->new('$args[0]'); \$x->digit($args[1]);";
+      } else { warn "Unknown op '$f'"; }
+    } # end else all other ops
+
+  $ans1 = eval $try;
+  # convert hex/binary targets to decimal	
+  if ($ans =~ /^(0x0x|0b0b)/)
+    {
+    $ans =~ s/^0[xb]//; $ans = Math::BigInt->new($ans)->bstr();
+    }
+  if ($ans eq "")
+    {
+    ok_undef ($ans1); 
+    }
+  else
+    {
+    # print "try: $try ans: $ans1 $ans\n";
+    print "# Tried: '$try'\n" if !ok ($ans1, $ans);
+    if ($expected_class ne $class)
+      {
+      ok (ref($ans1),$expected_class);	# also checks that it really is ref!
+      ok ($Math::BigInt::upgrade,'Math::BigFloat');	# still okay?
+      }
+    }
+  # check internal state of number objects
+  is_valid($ans1,$f) if ref $ans1; 
+  } # endwhile data tests
+close DATA;
+
+# all tests done
+
+1;
+
+###############################################################################
+###############################################################################
+# Perl 5.005 does not like ok ($x,undef)
+
+sub ok_undef
+  {
+  my $x = shift;
+
+  ok (1,1) and return if !defined $x;
+  ok ($x,'undef');
+  }
+
+###############################################################################
+# sub to check validity of a BigInt internally, to ensure that no op leaves a
+# number object in an invalid state (f.i. "-0")
+
+sub is_valid
+  {
+  my ($x,$f,$c) = @_;
+
+  # The checks here are loosened a bit to allow BigInt or BigFloats to pass
+
+  my $e = 0;			# error?
+  # ok as reference? 
+  # $e = "Not a reference to $c" if (ref($x) || '') ne $c;
+
+  # has ok sign?
+  $e = "Illegal sign $x->{sign} (expected: '+', '-', '-inf', '+inf' or 'NaN'"
+   if $e eq '0' && $x->{sign} !~ /^(\+|-|\+inf|-inf|NaN)$/;
+
+  $e = "-0 is invalid!" if $e ne '0' && $x->{sign} eq '-' && $x == 0;
+  #$e = $CALC->_check($x->{value}) if $e eq '0';
+
+  # test done, see if error did crop up
+  ok (1,1), return if ($e eq '0');
+
+  ok (1,$e." after op '$f'");
+  }
+
+__DATA__
+&.=
+1234:-345:1234-345
+&+=
+1:2:3
+-1:-2:-3
+&-=
+1:2:-1
+-1:-2:1
+&*=
+2:3:6
+-1:5:-5
+&%=
+100:3:1
+8:9:8
+&/=
+100:3:33
+-8:2:-4
+&|=
+2:1:3
+&&=
+5:7:5
+&^=
+5:7:2
+&is_negative
+0:0
+-1:1
+1:0
++inf:0
+-inf:1
+NaNneg:0
+&is_positive
+0:1
+-1:0
+1:1
++inf:1
+-inf:0
+NaNneg:0
+&is_odd
+abc:0
+0:0
+1:1
+3:1
+-1:1
+-3:1
+10000001:1
+10000002:0
+2:0
+120:0
+121:1
+&is_int
+NaN:0
+inf:0
+-inf:0
+1:1
+12:1
+123e12:1
+&is_even
+abc:0
+0:1
+1:0
+3:0
+-1:0
+-3:0
+10000001:0
+10000002:1
+2:1
+120:1
+121:0
+&bacmp
++0:-0:0
++0:+1:-1
+-1:+1:0
++1:-1:0
+-1:+2:-1
++2:-1:1
+-123456789:+987654321:-1
++123456789:-987654321:-1
++987654321:+123456789:1
+-987654321:+123456789:1
+-123:+4567889:-1
+# NaNs
+acmpNaN:123:
+123:acmpNaN:
+acmpNaN:acmpNaN:
+# infinity
++inf:+inf:0
+-inf:-inf:0
++inf:-inf:0
+-inf:+inf:0
++inf:123:1
+-inf:123:1
++inf:-123:1
+-inf:-123:1
+# return undef
++inf:NaN:
+NaN:inf:
+-inf:NaN:
+NaN:-inf:
+&bnorm
+123:123
+12.3:12.3^
+# binary input
+0babc:NaN
+0b123:NaN
+0b0:0
+-0b0:0
+-0b1:-1
+0b0001:1
+0b001:1
+0b011:3
+0b101:5
+0b1001:9
+0b10001:17
+0b100001:33
+0b1000001:65
+0b10000001:129
+0b100000001:257
+0b1000000001:513
+0b10000000001:1025
+0b100000000001:2049
+0b1000000000001:4097
+0b10000000000001:8193
+0b100000000000001:16385
+0b1000000000000001:32769
+0b10000000000000001:65537
+0b100000000000000001:131073
+0b1000000000000000001:262145
+0b10000000000000000001:524289
+0b100000000000000000001:1048577
+0b1000000000000000000001:2097153
+0b10000000000000000000001:4194305
+0b100000000000000000000001:8388609
+0b1000000000000000000000001:16777217
+0b10000000000000000000000001:33554433
+0b100000000000000000000000001:67108865
+0b1000000000000000000000000001:134217729
+0b10000000000000000000000000001:268435457
+0b100000000000000000000000000001:536870913
+0b1000000000000000000000000000001:1073741825
+0b10000000000000000000000000000001:2147483649
+0b100000000000000000000000000000001:4294967297
+0b1000000000000000000000000000000001:8589934593
+0b10000000000000000000000000000000001:17179869185
+0b_101:NaN
+0b1_0_1:5
+0b0_0_0_1:1
+# hex input
+-0x0:0
+0xabcdefgh:NaN
+0x1234:4660
+0xabcdef:11259375
+-0xABCDEF:-11259375
+-0x1234:-4660
+0x12345678:305419896
+0x1_2_3_4_56_78:305419896
+0xa_b_c_d_e_f:11259375
+0x_123:NaN
+0x9:9
+0x11:17
+0x21:33
+0x41:65
+0x81:129
+0x101:257
+0x201:513
+0x401:1025
+0x801:2049
+0x1001:4097
+0x2001:8193
+0x4001:16385
+0x8001:32769
+0x10001:65537
+0x20001:131073
+0x40001:262145
+0x80001:524289
+0x100001:1048577
+0x200001:2097153
+0x400001:4194305
+0x800001:8388609
+0x1000001:16777217
+0x2000001:33554433
+0x4000001:67108865
+0x8000001:134217729
+0x10000001:268435457
+0x20000001:536870913
+0x40000001:1073741825
+0x80000001:2147483649
+0x100000001:4294967297
+0x200000001:8589934593
+0x400000001:17179869185
+0x800000001:34359738369
+# inf input
+inf:inf
++inf:inf
+-inf:-inf
+0inf:NaN
+# abnormal input
+:NaN
+abc:NaN
+   1 a:NaN
+1bcd2:NaN
+11111b:NaN
++1z:NaN
+-1z:NaN
+# only one underscore between two digits
+_123:NaN
+_123_:NaN
+123_:NaN
+1__23:NaN
+1E1__2:NaN
+1_E12:NaN
+1E_12:NaN
+1_E_12:NaN
++_1E12:NaN
++0_1E2:100
++0_0_1E2:100
+-0_0_1E2:-100
+-0_0_1E+0_0_2:-100
+E1:NaN
+E23:NaN
+1.23E1:12.3^
+1.23E-1:0.123^
+# bug with two E's in number beeing valid
+1e2e3:NaN
+1e2r:NaN
+1e2.0:NaN
+# leading zeros
+012:12
+0123:123
+01234:1234
+012345:12345
+0123456:123456
+01234567:1234567
+012345678:12345678
+0123456789:123456789
+01234567891:1234567891
+012345678912:12345678912
+0123456789123:123456789123
+01234567891234:1234567891234
+# normal input
+0:0
++0:0
++00:0
++000:0
+000000000000000000:0
+-0:0
+-0000:0
++1:1
++01:1
++001:1
++00000100000:100000
+123456789:123456789
+-1:-1
+-01:-1
+-001:-1
+-123456789:-123456789
+-00000100000:-100000
+1_2_3:123
+10000000000E-1_0:1
+1E2:100
+1E1:10
+1E0:1
+1.23E2:123
+100E-1:10
+# floating point input
+# .2e2:20
+1.E3:1000
+1.01E2:101
+1010E-1:101
+-1010E0:-1010
+-1010E1:-10100
+1234.00:1234
+# non-integer numbers
+-1010E-2:-10.1^
+-1.01E+1:-10.1^
+-1.01E-1:-0.101^
+&bnan
+1:NaN
+2:NaN
+abc:NaN
+&bone
+2:+:1
+2:-:-1
+boneNaN:-:-1
+boneNaN:+:1
+2:abc:1
+3::1
+&binf
+1:+:inf
+2:-:-inf
+3:abc:inf
+&is_nan
+123:0
+abc:1
+NaN:1
+-123:0
+&is_inf
++inf::1
+-inf::1
+abc::0
+1::0
+NaN::0
+-1::0
++inf:-:0
++inf:+:1
+-inf:-:1
+-inf:+:0
+# it must be exactly /^[+-]inf$/
++infinity::0
+-infinity::0
+&blsft
+abc:abc:NaN
++2:+2:8
++1:+32:4294967296
++1:+48:281474976710656
++8:-2:NaN
+# excercise base 10
++12345:4:10:123450000
+-1234:0:10:-1234
++1234:0:10:1234
++2:2:10:200
++12:2:10:1200
++1234:-3:10:NaN
+1234567890123:12:10:1234567890123000000000000
+&brsft
+abc:abc:NaN
++8:+2:2
++4294967296:+32:1
++281474976710656:+48:1
++2:-2:NaN
+# excercise base 10
+-1234:0:10:-1234
++1234:0:10:1234
++200:2:10:2
++1234:3:10:1
++1234:2:10:12
++1234:-3:10:NaN
+310000:4:10:31
+12300000:5:10:123
+1230000000000:10:10:123
+09876123456789067890:12:10:9876123
+1234561234567890123:13:10:123456
+&bsstr
+1e+34:1e+34
+123.456E3:123456e+0
+100:1e+2
+abc:NaN
+&bneg
+bnegNaN:NaN
++inf:-inf
+-inf:inf
+abd:NaN
+0:0
+1:-1
+-1:1
++123456789:-123456789
+-123456789:123456789
+&babs
+babsNaN:NaN
++inf:inf
+-inf:inf
+0:0
+1:1
+-1:1
++123456789:123456789
+-123456789:123456789
+&bcmp
+bcmpNaN:bcmpNaN:
+bcmpNaN:0:
+0:bcmpNaN:
+0:0:0
+-1:0:-1
+0:-1:1
+1:0:1
+0:1:-1
+-1:1:-1
+1:-1:1
+-1:-1:0
+1:1:0
+123:123:0
+123:12:1
+12:123:-1
+-123:-123:0
+-123:-12:-1
+-12:-123:1
+123:124:-1
+124:123:1
+-123:-124:1
+-124:-123:-1
+100:5:1
+-123456789:987654321:-1
++123456789:-987654321:1
+-987654321:123456789:-1
+-inf:5432112345:-1
++inf:5432112345:1
+-inf:-5432112345:-1
++inf:-5432112345:1
++inf:+inf:0
+-inf:-inf:0
++inf:-inf:1
+-inf:+inf:-1
+5:inf:-1
+5:inf:-1
+-5:-inf:1
+-5:-inf:1
+# return undef
++inf:NaN:
+NaN:inf:
+-inf:NaN:
+NaN:-inf:
+&binc
+abc:NaN
++inf:inf
+-inf:-inf
++0:1
++1:2
+-1:0
+&bdec
+abc:NaN
++inf:inf
+-inf:-inf
++0:-1
++1:0
+-1:-2
+&badd
+abc:abc:NaN
+abc:0:NaN
++0:abc:NaN
++inf:-inf:NaN
+-inf:+inf:NaN
++inf:+inf:inf
+-inf:-inf:-inf
+baddNaN:+inf:NaN
+baddNaN:+inf:NaN
++inf:baddNaN:NaN
+-inf:baddNaN:NaN
+0:0:0
+1:0:1
+0:1:1
+1:1:2
+-1:0:-1
+0:-1:-1
+-1:-1:-2
+-1:+1:0
++1:-1:0
++9:+1:10
++99:+1:100
++999:+1:1000
++9999:+1:10000
++99999:+1:100000
++999999:+1:1000000
++9999999:+1:10000000
++99999999:+1:100000000
++999999999:+1:1000000000
++9999999999:+1:10000000000
++99999999999:+1:100000000000
++10:-1:9
++100:-1:99
++1000:-1:999
++10000:-1:9999
++100000:-1:99999
++1000000:-1:999999
++10000000:-1:9999999
++100000000:-1:99999999
++1000000000:-1:999999999
++10000000000:-1:9999999999
++123456789:987654321:1111111110
+-123456789:987654321:864197532
+-123456789:-987654321:-1111111110
++123456789:-987654321:-864197532
+#2:2.5:4.5^
+#-123:-1.5:-124.5^
+#-1.2:1:-0.2^
+&bsub
+abc:abc:NaN
+abc:+0:NaN
++0:abc:NaN
++inf:-inf:inf
+-inf:+inf:-inf
++inf:+inf:NaN
+-inf:-inf:NaN
++0:+0:0
++1:+0:1
++0:+1:-1
++1:+1:0
+-1:+0:-1
++0:-1:1
+-1:-1:0
+-1:+1:-2
++1:-1:2
++9:+1:8
++99:+1:98
++999:+1:998
++9999:+1:9998
++99999:+1:99998
++999999:+1:999998
++9999999:+1:9999998
++99999999:+1:99999998
++999999999:+1:999999998
++9999999999:+1:9999999998
++99999999999:+1:99999999998
++10:-1:11
++100:-1:101
++1000:-1:1001
++10000:-1:10001
++100000:-1:100001
++1000000:-1:1000001
++10000000:-1:10000001
++100000000:-1:100000001
++1000000000:-1:1000000001
++10000000000:-1:10000000001
++123456789:+987654321:-864197532
+-123456789:+987654321:-1111111110
+-123456789:-987654321:864197532
++123456789:-987654321:1111111110
+&bmul
+abc:abc:NaN
+abc:+0:NaN
++0:abc:NaN
+NaNmul:+inf:NaN
+NaNmul:-inf:NaN
+-inf:NaNmul:NaN
++inf:NaNmul:NaN
++inf:+inf:inf
++inf:-inf:-inf
+-inf:+inf:-inf
+-inf:-inf:inf
++0:+0:0
++0:+1:0
++1:+0:0
++0:-1:0
+-1:+0:0
+123456789123456789:0:0
+0:123456789123456789:0
+-1:-1:1
+-1:+1:-1
++1:-1:-1
++1:+1:1
++2:+3:6
+-2:+3:-6
++2:-3:-6
+-2:-3:6
+111:111:12321
+10101:10101:102030201
+1001001:1001001:1002003002001
+100010001:100010001:10002000300020001
+10000100001:10000100001:100002000030000200001
+11111111111:9:99999999999
+22222222222:9:199999999998
+33333333333:9:299999999997
+44444444444:9:399999999996
+55555555555:9:499999999995
+66666666666:9:599999999994
+77777777777:9:699999999993
+88888888888:9:799999999992
+99999999999:9:899999999991
++25:+25:625
++12345:+12345:152399025
++99999:+11111:1111088889
+9999:10000:99990000
+99999:100000:9999900000
+999999:1000000:999999000000
+9999999:10000000:99999990000000
+99999999:100000000:9999999900000000
+999999999:1000000000:999999999000000000
+9999999999:10000000000:99999999990000000000
+99999999999:100000000000:9999999999900000000000
+999999999999:1000000000000:999999999999000000000000
+9999999999999:10000000000000:99999999999990000000000000
+99999999999999:100000000000000:9999999999999900000000000000
+999999999999999:1000000000000000:999999999999999000000000000000
+9999999999999999:10000000000000000:99999999999999990000000000000000
+99999999999999999:100000000000000000:9999999999999999900000000000000000
+999999999999999999:1000000000000000000:999999999999999999000000000000000000
+9999999999999999999:10000000000000000000:99999999999999999990000000000000000000
+&bdiv-list
+100:20:5,0
+4095:4095:1,0
+-4095:-4095:1,0
+4095:-4095:-1,0
+-4095:4095:-1,0
+123:2:61,1
+9:5:1,4
+9:4:2,1
+# inf handling and general remainder
+5:8:0.625,5
+0:8:0,0
+11:2:5,1
+11:-2:-5,-1
+-11:2:-5,1
+# see table in documentation in MBI
+0:inf:0,0
+0:-inf:0,0
+5:inf:0,5
+5:-inf:0,5
+-5:inf:0,-5
+-5:-inf:0,-5
+inf:5:inf,0
+-inf:5:-inf,0
+inf:-5:-inf,0
+-inf:-5:inf,0
+5:5:1,0
+-5:-5:1,0
+inf:inf:NaN,NaN
+-inf:-inf:NaN,NaN
+-inf:inf:NaN,NaN
+inf:-inf:NaN,NaN
+8:0:inf,8
+inf:0:inf,inf
+# exceptions to reminder rule
+-8:0:-inf,-8
+-inf:0:-inf,-inf
+0:0:NaN,NaN
+&bdiv
+abc:abc:NaN
+abc:1:NaN
+1:abc:NaN
+0:0:NaN
+# inf handling (see table in doc)
+0:inf:0
+0:-inf:0
+5:inf:0
+5:-inf:0
+-5:inf:0
+-5:-inf:0
+inf:5:inf
+-inf:5:-inf
+inf:-5:-inf
+-inf:-5:inf
+5:5:1
+-5:-5:1
+inf:inf:NaN
+-inf:-inf:NaN
+-inf:inf:NaN
+inf:-inf:NaN
+8:0:inf
+inf:0:inf
+-8:0:-inf
+-inf:0:-inf
+0:0:NaN
+11:2:5
+-11:-2:5
+-11:2:-5
+11:-2:-5
+0:1:0
+0:-1:0
+1:1:1
+-1:-1:1
+1:-1:-1
+-1:1:-1
+1:2:0.5^
+2:1:2
+1000000000:9:111111111
+2000000000:9:222222222
+3000000000:9:333333333
+4000000000:9:444444444
+5000000000:9:555555555
+6000000000:9:666666666
+7000000000:9:777777777
+8000000000:9:888888888
+9000000000:9:1000000000
+35500000:113:314159
+71000000:226:314159
+106500000:339:314159
+1000000000:3:333333333
++10:+5:2
++100:+4:25
++1000:+8:125
++10000:+16:625
+999999999999:9:111111111111
+999999999999:99:10101010101
+999999999999:999:1001001001
+999999999999:9999:100010001
+999999999999999:99999:10000100001
++1111088889:99999:11111
+-5:-3:1
+-5:3:-1
+4:3:1
+4:-3:-1
+1:3:0.3333333333333333333333333333333333333333
+1:-3:-0.3333333333333333333333333333333333333333
+-2:-3:0.6666666666666666666666666666666666666667
+-2:3:-0.6666666666666666666666666666666666666667
+#8:5:1.6^
+#-8:5:-1.6^
+8:5:1
+-8:5:-1
+14:-3:-4
+-14:3:-4
+-14:-3:4
+14:3:4
+# bug in Calc with '99999' vs $BASE-1
+10000000000000000000000000000000000000000000000000000000000000000000000000000000000:10000000375084540248994272022843165711074:999999962491547381984643365663244474111576
+12:24:0.5^
+&bmod
+# inf handling, see table in doc
+0:inf:0
+0:-inf:0
+5:inf:5
+5:-inf:5
+-5:inf:-5
+-5:-inf:-5
+inf:5:0
+-inf:5:0
+inf:-5:0
+-inf:-5:0
+5:5:0
+-5:-5:0
+inf:inf:NaN
+-inf:-inf:NaN
+-inf:inf:NaN
+inf:-inf:NaN
+8:0:8
+inf:0:inf
+# exceptions to reminder rule
+-inf:0:-inf
+-8:0:-8
+0:0:NaN
+abc:abc:NaN
+abc:1:abc:NaN
+1:abc:NaN
+0:0:NaN
+0:1:0
+1:0:1
+0:-1:0
+-1:0:-1
+1:1:0
+-1:-1:0
+1:-1:0
+-1:1:0
+1:2:1
+2:1:0
+1000000000:9:1
+2000000000:9:2
+3000000000:9:3
+4000000000:9:4
+5000000000:9:5
+6000000000:9:6
+7000000000:9:7
+8000000000:9:8
+9000000000:9:0
+35500000:113:33
+71000000:226:66
+106500000:339:99
+1000000000:3:1
+10:5:0
+100:4:0
+1000:8:0
+10000:16:0
+999999999999:9:0
+999999999999:99:0
+999999999999:999:0
+999999999999:9999:0
+999999999999999:99999:0
+-9:+5:1
++9:-5:-1
+-9:-5:-4
+-5:3:1
+-2:3:1
+4:3:1
+1:3:1
+-5:-3:-2
+-2:-3:-2
+4:-3:-2
+1:-3:-2
+4095:4095:0
+100041000510123:3:0
+152403346:12345:4321
+9:5:4
+&bgcd
+abc:abc:NaN
+abc:+0:NaN
++0:abc:NaN
++0:+0:0
++0:+1:1
++1:+0:1
++1:+1:1
++2:+3:1
++3:+2:1
+-3:+2:1
+100:625:25
+4096:81:1
+1034:804:2
+27:90:56:1
+27:90:54:9
+&blcm
+abc:abc:NaN
+abc:+0:NaN
++0:abc:NaN
++0:+0:NaN
++1:+0:0
++0:+1:0
++27:+90:270
++1034:+804:415668
+&band
+abc:abc:NaN
+abc:0:NaN
+0:abc:NaN
+1:2:0
+3:2:2
++8:+2:0
++281474976710656:0:0
++281474976710656:1:0
++281474976710656:+281474976710656:281474976710656
+-2:-3:-4
+-1:-1:-1
+-6:-6:-6
+-7:-4:-8
+-7:4:0
+-4:7:4
+# equal arguments are treated special, so also do some test with unequal ones
+0xFFFF:0xFFFF:0x0xFFFF
+0xFFFFFF:0xFFFFFF:0x0xFFFFFF
+0xFFFFFFFF:0xFFFFFFFF:0x0xFFFFFFFF
+0xFFFFFFFFFF:0xFFFFFFFFFF:0x0xFFFFFFFFFF
+0xFFFFFFFFFFFF:0xFFFFFFFFFFFF:0x0xFFFFFFFFFFFF
+0xF0F0:0xF0F0:0x0xF0F0
+0x0F0F:0x0F0F:0x0x0F0F
+0xF0F0F0:0xF0F0F0:0x0xF0F0F0
+0x0F0F0F:0x0F0F0F:0x0x0F0F0F
+0xF0F0F0F0:0xF0F0F0F0:0x0xF0F0F0F0
+0x0F0F0F0F:0x0F0F0F0F:0x0x0F0F0F0F
+0xF0F0F0F0F0:0xF0F0F0F0F0:0x0xF0F0F0F0F0
+0x0F0F0F0F0F:0x0F0F0F0F0F:0x0x0F0F0F0F0F
+0xF0F0F0F0F0F0:0xF0F0F0F0F0F0:0x0xF0F0F0F0F0F0
+0x0F0F0F0F0F0F:0x0F0F0F0F0F0F:0x0x0F0F0F0F0F0F
+0x1F0F0F0F0F0F:0x3F0F0F0F0F0F:0x0x1F0F0F0F0F0F
+&bior
+abc:abc:NaN
+abc:0:NaN
+0:abc:NaN
+1:2:3
++8:+2:10
++281474976710656:0:281474976710656
++281474976710656:1:281474976710657
++281474976710656:281474976710656:281474976710656
+-2:-3:-1
+-1:-1:-1
+-6:-6:-6
+-7:4:-3
+-4:7:-1
+# equal arguments are treated special, so also do some test with unequal ones
+0xFFFF:0xFFFF:0x0xFFFF
+0xFFFFFF:0xFFFFFF:0x0xFFFFFF
+0xFFFFFFFF:0xFFFFFFFF:0x0xFFFFFFFF
+0xFFFFFFFFFF:0xFFFFFFFFFF:0x0xFFFFFFFFFF
+0xFFFFFFFFFFFF:0xFFFFFFFFFFFF:0x0xFFFFFFFFFFFF
+0:0xFFFF:0x0xFFFF
+0:0xFFFFFF:0x0xFFFFFF
+0:0xFFFFFFFF:0x0xFFFFFFFF
+0:0xFFFFFFFFFF:0x0xFFFFFFFFFF
+0:0xFFFFFFFFFFFF:0x0xFFFFFFFFFFFF
+0xFFFF:0:0x0xFFFF
+0xFFFFFF:0:0x0xFFFFFF
+0xFFFFFFFF:0:0x0xFFFFFFFF
+0xFFFFFFFFFF:0:0x0xFFFFFFFFFF
+0xFFFFFFFFFFFF:0:0x0xFFFFFFFFFFFF
+0xF0F0:0xF0F0:0x0xF0F0
+0x0F0F:0x0F0F:0x0x0F0F
+0xF0F0:0x0F0F:0x0xFFFF
+0xF0F0F0:0xF0F0F0:0x0xF0F0F0
+0x0F0F0F:0x0F0F0F:0x0x0F0F0F
+0x0F0F0F:0xF0F0F0:0x0xFFFFFF
+0xF0F0F0F0:0xF0F0F0F0:0x0xF0F0F0F0
+0x0F0F0F0F:0x0F0F0F0F:0x0x0F0F0F0F
+0x0F0F0F0F:0xF0F0F0F0:0x0xFFFFFFFF
+0xF0F0F0F0F0:0xF0F0F0F0F0:0x0xF0F0F0F0F0
+0x0F0F0F0F0F:0x0F0F0F0F0F:0x0x0F0F0F0F0F
+0x0F0F0F0F0F:0xF0F0F0F0F0:0x0xFFFFFFFFFF
+0xF0F0F0F0F0F0:0xF0F0F0F0F0F0:0x0xF0F0F0F0F0F0
+0x0F0F0F0F0F0F:0x0F0F0F0F0F0F:0x0x0F0F0F0F0F0F
+0x0F0F0F0F0F0F:0xF0F0F0F0F0F0:0x0xFFFFFFFFFFFF
+0x1F0F0F0F0F0F:0xF0F0F0F0F0F0:0x0xFFFFFFFFFFFF
+&bxor
+abc:abc:NaN
+abc:0:NaN
+0:abc:NaN
+1:2:3
++8:+2:10
++281474976710656:0:281474976710656
++281474976710656:1:281474976710657
++281474976710656:281474976710656:0
+-2:-3:3
+-1:-1:0
+-6:-6:0
+-7:4:-3
+-4:7:-5
+4:-7:-3
+-4:-7:5
+# equal arguments are treated special, so also do some test with unequal ones
+0xFFFF:0xFFFF:0
+0xFFFFFF:0xFFFFFF:0
+0xFFFFFFFF:0xFFFFFFFF:0
+0xFFFFFFFFFF:0xFFFFFFFFFF:0
+0xFFFFFFFFFFFF:0xFFFFFFFFFFFF:0
+0:0xFFFF:0x0xFFFF
+0:0xFFFFFF:0x0xFFFFFF
+0:0xFFFFFFFF:0x0xFFFFFFFF
+0:0xFFFFFFFFFF:0x0xFFFFFFFFFF
+0:0xFFFFFFFFFFFF:0x0xFFFFFFFFFFFF
+0xFFFF:0:0x0xFFFF
+0xFFFFFF:0:0x0xFFFFFF
+0xFFFFFFFF:0:0x0xFFFFFFFF
+0xFFFFFFFFFF:0:0x0xFFFFFFFFFF
+0xFFFFFFFFFFFF:0:0x0xFFFFFFFFFFFF
+0xF0F0:0xF0F0:0
+0x0F0F:0x0F0F:0
+0xF0F0:0x0F0F:0x0xFFFF
+0xF0F0F0:0xF0F0F0:0
+0x0F0F0F:0x0F0F0F:0
+0x0F0F0F:0xF0F0F0:0x0xFFFFFF
+0xF0F0F0F0:0xF0F0F0F0:0
+0x0F0F0F0F:0x0F0F0F0F:0
+0x0F0F0F0F:0xF0F0F0F0:0x0xFFFFFFFF
+0xF0F0F0F0F0:0xF0F0F0F0F0:0
+0x0F0F0F0F0F:0x0F0F0F0F0F:0
+0x0F0F0F0F0F:0xF0F0F0F0F0:0x0xFFFFFFFFFF
+0xF0F0F0F0F0F0:0xF0F0F0F0F0F0:0
+0x0F0F0F0F0F0F:0x0F0F0F0F0F0F:0
+0x0F0F0F0F0F0F:0xF0F0F0F0F0F0:0x0xFFFFFFFFFFFF
+&bnot
+abc:NaN
++0:-1
++8:-9
++281474976710656:-281474976710657
+-1:0
+-2:1
+-12:11
+&digit
+0:0:0
+12:0:2
+12:1:1
+123:0:3
+123:1:2
+123:2:1
+123:-1:1
+123:-2:2
+123:-3:3
+123456:0:6
+123456:1:5
+123456:2:4
+123456:3:3
+123456:4:2
+123456:5:1
+123456:-1:1
+123456:-2:2
+123456:-3:3
+100000:-3:0
+100000:0:0
+100000:1:0
+&mantissa
+abc:NaN
+1e4:1
+2e0:2
+123:123
+-1:-1
+-2:-2
++inf:inf
+-inf:-inf
+&exponent
+abc:NaN
+1e4:4
+2e0:0
+123:0
+-1:0
+-2:0
+0:1
++inf:inf
+-inf:inf
+&parts
+abc:NaN,NaN
+1e4:1,4
+2e0:2,0
+123:123,0
+-1:-1,0
+-2:-2,0
+0:0,1
++inf:inf,inf
+-inf:-inf,inf
+&bfac
+-1:NaN
+NaNfac:NaN
++inf:NaN
+-inf:NaN
+0:1
+1:1
+2:2
+3:6
+4:24
+5:120
+6:720
+10:3628800
+11:39916800
+12:479001600
+&bpow
+abc:12:NaN
+12:abc:NaN
+0:0:1
+0:1:0
+0:2:0
+0:-1:NaN
+0:-2:NaN
+1:0:1
+1:1:1
+1:2:1
+1:3:1
+1:-1:1
+1:-2:1
+1:-3:1
+2:0:1
+2:1:2
+2:2:4
+2:3:8
+3:3:27
+2:-1:NaN
+-2:-1:NaN
+2:-2:NaN
+-2:-2:NaN
++inf:1234500012:inf
+-inf:1234500012:-inf
++inf:-12345000123:inf
+-inf:-12345000123:-inf
+# 1 ** -x => 1 / (1 ** x)
+-1:0:1
+-2:0:1
+-1:1:-1
+-1:2:1
+-1:3:-1
+-1:4:1
+-1:5:-1
+-1:-1:-1
+-1:-2:1
+-1:-3:-1
+-1:-4:1
+10:2:100
+10:3:1000
+10:4:10000
+10:5:100000
+10:6:1000000
+10:7:10000000
+10:8:100000000
+10:9:1000000000
+10:20:100000000000000000000
+123456:2:15241383936
+&length
+100:3
+10:2
+1:1
+0:1
+12345:5
+10000000000000000:17
+-123:3
+215960156869840440586892398248:30
+&bsqrt
+145:12.04159457879229548012824103037860805243^
+144:12^
+143:11.95826074310139802112984075619561661399^
+16:4
+170:13.03840481040529742916594311485836883306^
+169:13
+168:12.96148139681572046193193487217599331541^
+4:2
+3:1.732050807568877293527446341505872366943^
+2:1.41421356237309504880168872420969807857^
+9:3
+12:3.464101615137754587054892683011744733886^
+256:16
+100000000:10000
+4000000000000:2000000
+152399026:12345.00004050222755607815159966235881398^
+152399025:12345
+152399024:12344.99995949777231103967404745303741942^
+1:1
+0:0
+-2:NaN
+-123:NaN
+Nan:NaN
++inf:NaN
+&bround
+$round_mode('trunc')
+0:12:0
+NaNbround:12:NaN
++inf:12:inf
+-inf:12:-inf
+1234:0:1234
+1234:2:1200
+123456:4:123400
+123456:5:123450
+123456:6:123456
++10123456789:5:10123000000
+-10123456789:5:-10123000000
++10123456789:9:10123456700
+-10123456789:9:-10123456700
++101234500:6:101234000
+-101234500:6:-101234000
+#+101234500:-4:101234000
+#-101234500:-4:-101234000
+$round_mode('zero')
++20123456789:5:20123000000
+-20123456789:5:-20123000000
++20123456789:9:20123456800
+-20123456789:9:-20123456800
++201234500:6:201234000
+-201234500:6:-201234000
+#+201234500:-4:201234000
+#-201234500:-4:-201234000
++12345000:4:12340000
+-12345000:4:-12340000
+$round_mode('+inf')
++30123456789:5:30123000000
+-30123456789:5:-30123000000
++30123456789:9:30123456800
+-30123456789:9:-30123456800
++301234500:6:301235000
+-301234500:6:-301234000
+#+301234500:-4:301235000
+#-301234500:-4:-301234000
++12345000:4:12350000
+-12345000:4:-12340000
+$round_mode('-inf')
++40123456789:5:40123000000
+-40123456789:5:-40123000000
++40123456789:9:40123456800
+-40123456789:9:-40123456800
++401234500:6:401234000
++401234500:6:401234000
+#-401234500:-4:-401235000
+#-401234500:-4:-401235000
++12345000:4:12340000
+-12345000:4:-12350000
+$round_mode('odd')
++50123456789:5:50123000000
+-50123456789:5:-50123000000
++50123456789:9:50123456800
+-50123456789:9:-50123456800
++501234500:6:501235000
+-501234500:6:-501235000
+#+501234500:-4:501235000
+#-501234500:-4:-501235000
++12345000:4:12350000
+-12345000:4:-12350000
+$round_mode('even')
++60123456789:5:60123000000
+-60123456789:5:-60123000000
++60123456789:9:60123456800
+-60123456789:9:-60123456800
++601234500:6:601234000
+-601234500:6:-601234000
+#+601234500:-4:601234000
+#-601234500:-4:-601234000
+#-601234500:-9:0
+#-501234500:-9:0
+#-601234500:-8:0
+#-501234500:-8:0
++1234567:7:1234567
++1234567:6:1234570
++12345000:4:12340000
+-12345000:4:-12340000
+&is_zero
+0:1
+NaNzero:0
++inf:0
+-inf:0
+123:0
+-1:0
+1:0
+&is_one
+0:0
+NaNone:0
++inf:0
+-inf:0
+1:1
+2:0
+-1:0
+-2:0
+# floor and ceil tests are pretty pointless in integer space...but play safe
+&bfloor
+0:0
+NaNfloor:NaN
++inf:inf
+-inf:-inf
+-1:-1
+-2:-2
+2:2
+3:3
+abc:NaN
+&bceil
+NaNceil:NaN
++inf:inf
+-inf:-inf
+0:0
+-1:-1
+-2:-2
+2:2
+3:3
+abc:NaN
+&as_hex
+128:0x80
+-128:-0x80
+0:0x0
+-0:0x0
+1:0x1
+0x123456789123456789:0x123456789123456789
++inf:inf
+-inf:-inf
+NaNas_hex:NaN
+&as_bin
+128:0b10000000
+-128:-0b10000000
+0:0b0
+-0:0b0
+1:0b1
+0b1010111101010101010110110110110110101:0b1010111101010101010110110110110110101
++inf:inf
+-inf:-inf
+NaNas_bin:NaN
diff --git a/lib/Math/BigInt/t/upgrade.t b/lib/Math/BigInt/t/upgrade.t
new file mode 100644
index 0000000..297d526
--- /dev/null
+++ b/lib/Math/BigInt/t/upgrade.t
@@ -0,0 +1,42 @@
+#!/usr/bin/perl -w
+
+use Test;
+use strict;
+
+BEGIN
+  {
+  $| = 1;
+  # to locate the testing files
+  my $location = $0; $location =~ s/upgrade.t//i;
+  if ($ENV{PERL_CORE})
+    {
+    @INC = qw(../t/lib);                # testing with the core distribution
+    }
+  unshift @INC, '../lib';       # for testing manually
+  if (-d 't')
+    {
+    chdir 't';
+    require File::Spec;
+    unshift @INC, File::Spec->catdir(File::Spec->updir, $location);
+    }
+  else
+    {
+    unshift @INC, $location;
+    }
+  print "# INC = @INC\n";
+
+  plan tests => 1991;
+  }
+
+use Math::BigInt upgrade => 'Math::BigFloat';
+use Math::BigFloat;
+
+use vars qw ($scale $class $try $x $y $f @args $ans $ans1 $ans1_str $setup
+             $ECL $CL);
+$class = "Math::BigInt";
+$CL = "Math::BigInt::Calc";
+$ECL = "Math::BigFloat";
+
+ok (Math::BigInt->upgrade(),'Math::BigFloat');
+
+require 'upgrade.inc';	# all tests here for sharing
diff --git a/t/lib/Math/BigFloat/Subclass.pm b/t/lib/Math/BigFloat/Subclass.pm
index ca9bbce..db8ccb7 100644
--- a/t/lib/Math/BigFloat/Subclass.pm
+++ b/t/lib/Math/BigFloat/Subclass.pm
@@ -12,7 +12,9 @@ use vars qw($VERSION @ISA $PACKAGE
 
 @ISA = qw(Exporter Math::BigFloat);
 
-$VERSION = 0.02;
+$VERSION = 0.03;
+
+use overload; 		# inherit overload from BigInt
 
 # Globals
 $accuracy = $precision = undef;
diff --git a/t/lib/Math/BigInt/Subclass.pm b/t/lib/Math/BigInt/Subclass.pm
index 03795da..0ec798b 100644
--- a/t/lib/Math/BigInt/Subclass.pm
+++ b/t/lib/Math/BigInt/Subclass.pm
@@ -13,7 +13,9 @@ use vars qw($VERSION @ISA $PACKAGE @EXPORT_OK
 @ISA = qw(Exporter Math::BigInt);
 @EXPORT_OK = qw(bgcd);
 
-$VERSION = 0.02;
+$VERSION = 0.03;
+
+use overload;	# inherit overload from BigInt
 
 # Globals
 $accuracy = $precision = undef;