X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMath%2FBigInt.pm;h=a43969c2b2328aa7dcd10e2bfd81ba9967273ea5;hb=74a2feed3f7ab8f6e9b1144cca2f3eb4f6fd9498;hp=b8ad6cec1faa43490b2f5b0c72b2cdc9e77253e1;hpb=5d7098d560a042a848a6e60f96567ce4b694c6c7;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/lib/Math/BigInt.pm b/lib/Math/BigInt.pm
index b8ad6ce..a43969c 100644
--- a/lib/Math/BigInt.pm
+++ b/lib/Math/BigInt.pm
@@ -16,6 +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
@@ -257,8 +265,10 @@ sub bdiv { #(dividend: num_str, divisor: num_str) return num_str
 	push(@x, 0);
     }
     @q = (); ($v2,$v1) = @y[-2,-1];
+    $v2 = 0 unless $v2;
     while ($#x > $#y) {
 	($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) {
@@ -326,6 +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__
 
@@ -348,6 +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