remove unused interpreter globals

[p5sagit/p5-mst-13.2.git] / lib / Math / BigInt.pm

diff --git a/lib/Math/BigInt.pm b/lib/Math/BigInt.pm
index cd5c221..a43969c 100644 (file)
--- a/lib/Math/BigInt.pm
+++ b/lib/Math/BigInt.pm
@@ -4,10 +4,8 @@ use overload
 '+'    =>      sub {new Math::BigInt &badd},
 '-'    =>      sub {new Math::BigInt
                       $_[2]? bsub($_[1],${$_[0]}) : bsub(${$_[0]},$_[1])},
-'<=>'  =>      sub {new Math::BigInt
-                      $_[2]? bcmp($_[1],${$_[0]}) : bcmp(${$_[0]},$_[1])},
-'cmp'  =>      sub {new Math::BigInt
-                      $_[2]? ($_[1] cmp ${$_[0]}) : (${$_[0]} cmp $_[1])},
+'<=>'  =>      sub {$_[2]? bcmp($_[1],${$_[0]}) : bcmp(${$_[0]},$_[1])},
+'cmp'  =>      sub {$_[2]? ($_[1] cmp ${$_[0]}) : (${$_[0]} cmp $_[1])},
 '*'    =>      sub {new Math::BigInt &bmul},
 '/'    =>      sub {new Math::BigInt 
                       $_[2]? scalar bdiv($_[1],${$_[0]}) :
@@ -18,6 +16,14 @@ use overload
                       $_[2]? bpow($_[1],${$_[0]}) : bpow(${$_[0]},$_[1])},
 'neg'  =>      sub {new Math::BigInt &bneg},
 'abs'  =>      sub {new Math::BigInt &babs},
+'<<'   =>      sub {new Math::BigInt
+                      $_[2]? blsft($_[1],${$_[0]}) : blsft(${$_[0]},$_[1])},
+'>>'   =>      sub {new Math::BigInt
+                      $_[2]? brsft($_[1],${$_[0]}) : brsft(${$_[0]},$_[1])},
+'&'    =>      sub {new Math::BigInt &band},
+'|'    =>      sub {new Math::BigInt &bior},
+'^'    =>      sub {new Math::BigInt &bxor},
+'~'    =>      sub {new Math::BigInt &bnot},
 
 qw(
 ""     stringify
@@ -258,9 +264,11 @@ sub bdiv { #(dividend: num_str, divisor: num_str) return num_str
     else {
        push(@x, 0);
     }
-    @q = (); ($v2,$v1) = ($y[-2] || 0, $y[-1]);
+    @q = (); ($v2,$v1) = @y[-2,-1];
+    $v2 = 0 unless $v2;
     while ($#x > $#y) {
-       ($u2,$u1,$u0) = ($x[-3] || 0, $x[-2] || 0, $x[-1]);
+       ($u2,$u1,$u0) = @x[-3..-1];
+       $u2 = 0 unless $u2;
        $q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1));
        --$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*1e5+$u2);
        if ($q) {
@@ -328,6 +336,69 @@ sub bpow { #(num_str, num_str) return num_str
     }
 }
 
+# compute x << y, y >= 0
+sub blsft { #(num_str, num_str) return num_str
+    &bmul($_[$[], &bpow(2, $_[$[+1]));
+}
+
+# compute x >> y, y >= 0
+sub brsft { #(num_str, num_str) return num_str
+    &bdiv($_[$[], &bpow(2, $_[$[+1]));
+}
+
+# compute x & y
+sub band { #(num_str, num_str) return num_str
+    local($x,$y,$r,$m,$xr,$yr) = (&bnorm($_[$[]),&bnorm($_[$[+1]),0,1);
+    if ($x eq 'NaN' || $y eq 'NaN') {
+       'NaN';
+    } else {
+       while ($x ne '+0' && $y ne '+0') {
+           ($x, $xr) = &bdiv($x, 0x10000);
+           ($y, $yr) = &bdiv($y, 0x10000);
+           $r = &badd(&bmul(int $xr & $yr, $m), $r);
+           $m = &bmul($m, 0x10000);
+       }
+       $r;
+    }
+}
+
+# compute x | y
+sub bior { #(num_str, num_str) return num_str
+    local($x,$y,$r,$m,$xr,$yr) = (&bnorm($_[$[]),&bnorm($_[$[+1]),0,1);
+    if ($x eq 'NaN' || $y eq 'NaN') {
+       'NaN';
+    } else {
+       while ($x ne '+0' || $y ne '+0') {
+           ($x, $xr) = &bdiv($x, 0x10000);
+           ($y, $yr) = &bdiv($y, 0x10000);
+           $r = &badd(&bmul(int $xr | $yr, $m), $r);
+           $m = &bmul($m, 0x10000);
+       }
+       $r;
+    }
+}
+
+# compute x ^ y
+sub bxor { #(num_str, num_str) return num_str
+    local($x,$y,$r,$m,$xr,$yr) = (&bnorm($_[$[]),&bnorm($_[$[+1]),0,1);
+    if ($x eq 'NaN' || $y eq 'NaN') {
+       'NaN';
+    } else {
+       while ($x ne '+0' || $y ne '+0') {
+           ($x, $xr) = &bdiv($x, 0x10000);
+           ($y, $yr) = &bdiv($y, 0x10000);
+           $r = &badd(&bmul(int $xr ^ $yr, $m), $r);
+           $m = &bmul($m, 0x10000);
+       }
+       $r;
+    }
+}
+
+# represent ~x as twos-complement number
+sub bnot { #(num_str) return num_str
+    &bsub(-1,$_[$[]);
+}
+
 1;
 __END__
 
@@ -350,6 +421,12 @@ Math::BigInt - Arbitrary size integer math package
   $i->bmod(BINT) return BINT         modulus
   $i->bgcd(BINT) return BINT         greatest common divisor
   $i->bnorm return BINT              normalization
+  $i->blsft(BINT) return BINT        left shift
+  $i->brsft(BINT) return (BINT,BINT) right shift (quo,rem) just quo if scalar
+  $i->band(BINT) return BINT         bit-wise and
+  $i->bior(BINT) return BINT         bit-wise inclusive or
+  $i->bxor(BINT) return BINT         bit-wise exclusive or
+  $i->bnot return BINT               bit-wise not
 
 =head1 DESCRIPTION
 
@@ -400,8 +477,8 @@ In particular
 
   perl -MMath::BigInt=:constant -e 'print 2**100'
 
-print the integer value of C<2**100>.  Note that without convertion of 
-constants the expression 2**100 will be calculatted as floating point number.
+print the integer value of C<2**100>.  Note that without conversion of 
+constants the expression 2**100 will be calculated as floating point number.
 
 =head1 BUGS