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package Math::BigInt::CalcEmu; |
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|
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use 5.005; |
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use strict; |
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# use warnings; # dont use warnings for older Perls |
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use vars qw/$VERSION/; |
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|
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$VERSION = '0.05'; |
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|
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package Math::BigInt; |
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|
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# See SYNOPSIS below. |
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|
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my $CALC_EMU; |
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|
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BEGIN |
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{ |
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$CALC_EMU = Math::BigInt->config()->{'lib'}; |
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# register us with MBI to get notified of future lib changes |
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Math::BigInt::_register_callback( __PACKAGE__, sub { $CALC_EMU = $_[0]; } ); |
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} |
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|
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sub __emu_band |
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{ |
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my ($self,$x,$y,$sx,$sy,@r) = @_; |
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|
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return $x->bzero(@r) if $y->is_zero() || $x->is_zero(); |
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|
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my $sign = 0; # sign of result |
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$sign = 1 if $sx == -1 && $sy == -1; |
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|
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my ($bx,$by); |
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|
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if ($sx == -1) # if x is negative |
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{ |
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# two's complement: inc and flip all "bits" in $bx |
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$bx = $x->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
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$bx =~ s/-?0x//; |
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$bx =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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else |
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{ |
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$bx = $x->as_hex(); # get binary representation |
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$bx =~ s/-?0x//; |
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$bx =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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if ($sy == -1) # if y is negative |
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{ |
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# two's complement: inc and flip all "bits" in $by |
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$by = $y->copy()->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
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$by =~ s/-?0x//; |
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$by =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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else |
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{ |
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$by = $y->as_hex(); # get binary representation |
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$by =~ s/-?0x//; |
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$by =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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# now we have bit-strings from X and Y, reverse them for padding |
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$bx = reverse $bx; |
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$by = reverse $by; |
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|
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# padd the shorter string |
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my $xx = "\x00"; $xx = "\x0f" if $sx == -1; |
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my $yy = "\x00"; $yy = "\x0f" if $sy == -1; |
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my $diff = CORE::length($bx) - CORE::length($by); |
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if ($diff > 0) |
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{ |
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# if $yy eq "\x00", we can cut $bx, otherwise we need to padd $by |
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$by .= $yy x $diff; |
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} |
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elsif ($diff < 0) |
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{ |
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# if $xx eq "\x00", we can cut $by, otherwise we need to padd $bx |
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$bx .= $xx x abs($diff); |
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} |
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|
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# and the strings together |
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my $r = $bx & $by; |
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|
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# and reverse the result again |
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$bx = reverse $r; |
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|
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# One of $x or $y was negative, so need to flip bits in the result. |
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# In both cases (one or two of them negative, or both positive) we need |
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# to get the characters back. |
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if ($sign == 1) |
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{ |
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$bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/0123456789abcdef/; |
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} |
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else |
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{ |
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$bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/fedcba9876543210/; |
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} |
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|
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# leading zeros will be stripped by _from_hex() |
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$bx = '0x' . $bx; |
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$x->{value} = $CALC_EMU->_from_hex( $bx ); |
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|
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# calculate sign of result |
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$x->{sign} = '+'; |
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$x->{sign} = '-' if $sign == 1 && !$x->is_zero(); |
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|
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$x->bdec() if $sign == 1; |
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|
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$x->round(@r); |
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} |
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|
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sub __emu_bior |
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{ |
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my ($self,$x,$y,$sx,$sy,@r) = @_; |
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|
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return $x->round(@r) if $y->is_zero(); |
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|
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my $sign = 0; # sign of result |
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$sign = 1 if ($sx == -1) || ($sy == -1); |
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|
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my ($bx,$by); |
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|
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if ($sx == -1) # if x is negative |
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{ |
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# two's complement: inc and flip all "bits" in $bx |
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$bx = $x->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
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$bx =~ s/-?0x//; |
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$bx =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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else |
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{ |
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$bx = $x->as_hex(); # get binary representation |
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$bx =~ s/-?0x//; |
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$bx =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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if ($sy == -1) # if y is negative |
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{ |
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# two's complement: inc and flip all "bits" in $by |
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$by = $y->copy()->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
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$by =~ s/-?0x//; |
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$by =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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else |
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{ |
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$by = $y->as_hex(); # get binary representation |
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$by =~ s/-?0x//; |
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$by =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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# now we have bit-strings from X and Y, reverse them for padding |
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$bx = reverse $bx; |
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$by = reverse $by; |
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|
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# padd the shorter string |
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my $xx = "\x00"; $xx = "\x0f" if $sx == -1; |
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my $yy = "\x00"; $yy = "\x0f" if $sy == -1; |
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my $diff = CORE::length($bx) - CORE::length($by); |
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if ($diff > 0) |
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{ |
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$by .= $yy x $diff; |
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} |
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elsif ($diff < 0) |
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{ |
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$bx .= $xx x abs($diff); |
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} |
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|
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# or the strings together |
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my $r = $bx | $by; |
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|
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# and reverse the result again |
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$bx = reverse $r; |
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|
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# one of $x or $y was negative, so need to flip bits in the result |
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# in both cases (one or two of them negative, or both positive) we need |
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# to get the characters back. |
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if ($sign == 1) |
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{ |
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$bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/0123456789abcdef/; |
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} |
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else |
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{ |
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$bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/fedcba9876543210/; |
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} |
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|
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# leading zeros will be stripped by _from_hex() |
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$bx = '0x' . $bx; |
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$x->{value} = $CALC_EMU->_from_hex( $bx ); |
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|
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# calculate sign of result |
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$x->{sign} = '+'; |
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$x->{sign} = '-' if $sign == 1 && !$x->is_zero(); |
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|
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# if one of X or Y was negative, we need to decrement result |
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$x->bdec() if $sign == 1; |
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|
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$x->round(@r); |
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} |
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|
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sub __emu_bxor |
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{ |
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my ($self,$x,$y,$sx,$sy,@r) = @_; |
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|
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return $x->round(@r) if $y->is_zero(); |
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|
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my $sign = 0; # sign of result |
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$sign = 1 if $x->{sign} ne $y->{sign}; |
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|
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my ($bx,$by); |
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|
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if ($sx == -1) # if x is negative |
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{ |
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# two's complement: inc and flip all "bits" in $bx |
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$bx = $x->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
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$bx =~ s/-?0x//; |
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$bx =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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else |
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{ |
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$bx = $x->as_hex(); # get binary representation |
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$bx =~ s/-?0x//; |
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$bx =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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if ($sy == -1) # if y is negative |
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{ |
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# two's complement: inc and flip all "bits" in $by |
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$by = $y->copy()->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
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$by =~ s/-?0x//; |
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$by =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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else |
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{ |
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$by = $y->as_hex(); # get binary representation |
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$by =~ s/-?0x//; |
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$by =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
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} |
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# now we have bit-strings from X and Y, reverse them for padding |
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$bx = reverse $bx; |
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$by = reverse $by; |
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|
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# padd the shorter string |
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my $xx = "\x00"; $xx = "\x0f" if $sx == -1; |
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my $yy = "\x00"; $yy = "\x0f" if $sy == -1; |
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my $diff = CORE::length($bx) - CORE::length($by); |
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if ($diff > 0) |
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{ |
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$by .= $yy x $diff; |
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} |
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elsif ($diff < 0) |
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{ |
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$bx .= $xx x abs($diff); |
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} |
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|
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# xor the strings together |
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my $r = $bx ^ $by; |
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|
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# and reverse the result again |
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$bx = reverse $r; |
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|
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# one of $x or $y was negative, so need to flip bits in the result |
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# in both cases (one or two of them negative, or both positive) we need |
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# to get the characters back. |
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if ($sign == 1) |
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{ |
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$bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/0123456789abcdef/; |
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} |
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else |
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{ |
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$bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/fedcba9876543210/; |
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} |
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|
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# leading zeros will be stripped by _from_hex() |
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$bx = '0x' . $bx; |
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$x->{value} = $CALC_EMU->_from_hex( $bx ); |
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|
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# calculate sign of result |
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$x->{sign} = '+'; |
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$x->{sign} = '-' if $sx != $sy && !$x->is_zero(); |
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|
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$x->bdec() if $sign == 1; |
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|
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$x->round(@r); |
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} |
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|
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############################################################################## |
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############################################################################## |
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|
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1; |
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__END__ |
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|
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=head1 NAME |
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|
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Math::BigInt::CalcEmu - Emulate low-level math with BigInt code |
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|
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=head1 SYNOPSIS |
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|
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use Math::BigInt::CalcEmu; |
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|
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=head1 DESCRIPTION |
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|
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Contains routines that emulate low-level math functions in BigInt, e.g. |
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optional routines the low-level math package does not provide on it's own. |
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|
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Will be loaded on demand and called automatically by BigInt. |
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|
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Stuff here is really low-priority to optimize, since it is far better to |
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implement the operation in the low-level math libary directly, possible even |
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using a call to the native lib. |
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|
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=head1 METHODS |
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|
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=head2 __emu_bxor |
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|
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=head2 __emu_band |
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|
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=head2 __emu_bior |
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|
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=head1 LICENSE |
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|
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This program is free software; you may redistribute it and/or modify it under |
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the same terms as Perl itself. |
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|
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=head1 AUTHORS |
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|
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(c) Tels http://bloodgate.com 2003, 2004 - based on BigInt code by |
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Tels from 2001-2003. |
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|
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=head1 SEE ALSO |
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|
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L<Math::BigInt>, L<Math::BigFloat>, L<Math::BigInt::BitVect>, |
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L<Math::BigInt::GMP> and L<Math::BigInt::Pari>. |
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|
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=cut |
