| 1 | package Math::BigInt::CalcEmu; |
| 2 | |
| 3 | use 5.005; |
| 4 | use strict; |
| 5 | # use warnings; # dont use warnings for older Perls |
| 6 | use vars qw/$VERSION/; |
| 7 | |
| 8 | $VERSION = '0.05'; |
| 9 | |
| 10 | package Math::BigInt; |
| 11 | |
| 12 | # See SYNOPSIS below. |
| 13 | |
| 14 | my $CALC_EMU; |
| 15 | |
| 16 | BEGIN |
| 17 | { |
| 18 | $CALC_EMU = Math::BigInt->config()->{'lib'}; |
| 19 | # register us with MBI to get notified of future lib changes |
| 20 | Math::BigInt::_register_callback( __PACKAGE__, sub { $CALC_EMU = $_[0]; } ); |
| 21 | } |
| 22 | |
| 23 | sub __emu_band |
| 24 | { |
| 25 | my ($self,$x,$y,$sx,$sy,@r) = @_; |
| 26 | |
| 27 | return $x->bzero(@r) if $y->is_zero() || $x->is_zero(); |
| 28 | |
| 29 | my $sign = 0; # sign of result |
| 30 | $sign = 1 if $sx == -1 && $sy == -1; |
| 31 | |
| 32 | my ($bx,$by); |
| 33 | |
| 34 | if ($sx == -1) # if x is negative |
| 35 | { |
| 36 | # two's complement: inc and flip all "bits" in $bx |
| 37 | $bx = $x->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
| 38 | $bx =~ s/-?0x//; |
| 39 | $bx =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 40 | } |
| 41 | else |
| 42 | { |
| 43 | $bx = $x->as_hex(); # get binary representation |
| 44 | $bx =~ s/-?0x//; |
| 45 | $bx =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 46 | } |
| 47 | if ($sy == -1) # if y is negative |
| 48 | { |
| 49 | # two's complement: inc and flip all "bits" in $by |
| 50 | $by = $y->copy()->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
| 51 | $by =~ s/-?0x//; |
| 52 | $by =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 53 | } |
| 54 | else |
| 55 | { |
| 56 | $by = $y->as_hex(); # get binary representation |
| 57 | $by =~ s/-?0x//; |
| 58 | $by =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 59 | } |
| 60 | # now we have bit-strings from X and Y, reverse them for padding |
| 61 | $bx = reverse $bx; |
| 62 | $by = reverse $by; |
| 63 | |
| 64 | # padd the shorter string |
| 65 | my $xx = "\x00"; $xx = "\x0f" if $sx == -1; |
| 66 | my $yy = "\x00"; $yy = "\x0f" if $sy == -1; |
| 67 | my $diff = CORE::length($bx) - CORE::length($by); |
| 68 | if ($diff > 0) |
| 69 | { |
| 70 | # if $yy eq "\x00", we can cut $bx, otherwise we need to padd $by |
| 71 | $by .= $yy x $diff; |
| 72 | } |
| 73 | elsif ($diff < 0) |
| 74 | { |
| 75 | # if $xx eq "\x00", we can cut $by, otherwise we need to padd $bx |
| 76 | $bx .= $xx x abs($diff); |
| 77 | } |
| 78 | |
| 79 | # and the strings together |
| 80 | my $r = $bx & $by; |
| 81 | |
| 82 | # and reverse the result again |
| 83 | $bx = reverse $r; |
| 84 | |
| 85 | # One of $x or $y was negative, so need to flip bits in the result. |
| 86 | # In both cases (one or two of them negative, or both positive) we need |
| 87 | # to get the characters back. |
| 88 | if ($sign == 1) |
| 89 | { |
| 90 | $bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/0123456789abcdef/; |
| 91 | } |
| 92 | else |
| 93 | { |
| 94 | $bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/fedcba9876543210/; |
| 95 | } |
| 96 | |
| 97 | # leading zeros will be stripped by _from_hex() |
| 98 | $bx = '0x' . $bx; |
| 99 | $x->{value} = $CALC_EMU->_from_hex( $bx ); |
| 100 | |
| 101 | # calculate sign of result |
| 102 | $x->{sign} = '+'; |
| 103 | $x->{sign} = '-' if $sign == 1 && !$x->is_zero(); |
| 104 | |
| 105 | $x->bdec() if $sign == 1; |
| 106 | |
| 107 | $x->round(@r); |
| 108 | } |
| 109 | |
| 110 | sub __emu_bior |
| 111 | { |
| 112 | my ($self,$x,$y,$sx,$sy,@r) = @_; |
| 113 | |
| 114 | return $x->round(@r) if $y->is_zero(); |
| 115 | |
| 116 | my $sign = 0; # sign of result |
| 117 | $sign = 1 if ($sx == -1) || ($sy == -1); |
| 118 | |
| 119 | my ($bx,$by); |
| 120 | |
| 121 | if ($sx == -1) # if x is negative |
| 122 | { |
| 123 | # two's complement: inc and flip all "bits" in $bx |
| 124 | $bx = $x->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
| 125 | $bx =~ s/-?0x//; |
| 126 | $bx =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 127 | } |
| 128 | else |
| 129 | { |
| 130 | $bx = $x->as_hex(); # get binary representation |
| 131 | $bx =~ s/-?0x//; |
| 132 | $bx =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 133 | } |
| 134 | if ($sy == -1) # if y is negative |
| 135 | { |
| 136 | # two's complement: inc and flip all "bits" in $by |
| 137 | $by = $y->copy()->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
| 138 | $by =~ s/-?0x//; |
| 139 | $by =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 140 | } |
| 141 | else |
| 142 | { |
| 143 | $by = $y->as_hex(); # get binary representation |
| 144 | $by =~ s/-?0x//; |
| 145 | $by =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 146 | } |
| 147 | # now we have bit-strings from X and Y, reverse them for padding |
| 148 | $bx = reverse $bx; |
| 149 | $by = reverse $by; |
| 150 | |
| 151 | # padd the shorter string |
| 152 | my $xx = "\x00"; $xx = "\x0f" if $sx == -1; |
| 153 | my $yy = "\x00"; $yy = "\x0f" if $sy == -1; |
| 154 | my $diff = CORE::length($bx) - CORE::length($by); |
| 155 | if ($diff > 0) |
| 156 | { |
| 157 | $by .= $yy x $diff; |
| 158 | } |
| 159 | elsif ($diff < 0) |
| 160 | { |
| 161 | $bx .= $xx x abs($diff); |
| 162 | } |
| 163 | |
| 164 | # or the strings together |
| 165 | my $r = $bx | $by; |
| 166 | |
| 167 | # and reverse the result again |
| 168 | $bx = reverse $r; |
| 169 | |
| 170 | # one of $x or $y was negative, so need to flip bits in the result |
| 171 | # in both cases (one or two of them negative, or both positive) we need |
| 172 | # to get the characters back. |
| 173 | if ($sign == 1) |
| 174 | { |
| 175 | $bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/0123456789abcdef/; |
| 176 | } |
| 177 | else |
| 178 | { |
| 179 | $bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/fedcba9876543210/; |
| 180 | } |
| 181 | |
| 182 | # leading zeros will be stripped by _from_hex() |
| 183 | $bx = '0x' . $bx; |
| 184 | $x->{value} = $CALC_EMU->_from_hex( $bx ); |
| 185 | |
| 186 | # calculate sign of result |
| 187 | $x->{sign} = '+'; |
| 188 | $x->{sign} = '-' if $sign == 1 && !$x->is_zero(); |
| 189 | |
| 190 | # if one of X or Y was negative, we need to decrement result |
| 191 | $x->bdec() if $sign == 1; |
| 192 | |
| 193 | $x->round(@r); |
| 194 | } |
| 195 | |
| 196 | sub __emu_bxor |
| 197 | { |
| 198 | my ($self,$x,$y,$sx,$sy,@r) = @_; |
| 199 | |
| 200 | return $x->round(@r) if $y->is_zero(); |
| 201 | |
| 202 | my $sign = 0; # sign of result |
| 203 | $sign = 1 if $x->{sign} ne $y->{sign}; |
| 204 | |
| 205 | my ($bx,$by); |
| 206 | |
| 207 | if ($sx == -1) # if x is negative |
| 208 | { |
| 209 | # two's complement: inc and flip all "bits" in $bx |
| 210 | $bx = $x->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
| 211 | $bx =~ s/-?0x//; |
| 212 | $bx =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 213 | } |
| 214 | else |
| 215 | { |
| 216 | $bx = $x->as_hex(); # get binary representation |
| 217 | $bx =~ s/-?0x//; |
| 218 | $bx =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 219 | } |
| 220 | if ($sy == -1) # if y is negative |
| 221 | { |
| 222 | # two's complement: inc and flip all "bits" in $by |
| 223 | $by = $y->copy()->binc()->as_hex(); # -1 => 0, -2 => 1, -3 => 2 etc |
| 224 | $by =~ s/-?0x//; |
| 225 | $by =~ tr/0123456789abcdef/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 226 | } |
| 227 | else |
| 228 | { |
| 229 | $by = $y->as_hex(); # get binary representation |
| 230 | $by =~ s/-?0x//; |
| 231 | $by =~ tr/fedcba9876543210/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/; |
| 232 | } |
| 233 | # now we have bit-strings from X and Y, reverse them for padding |
| 234 | $bx = reverse $bx; |
| 235 | $by = reverse $by; |
| 236 | |
| 237 | # padd the shorter string |
| 238 | my $xx = "\x00"; $xx = "\x0f" if $sx == -1; |
| 239 | my $yy = "\x00"; $yy = "\x0f" if $sy == -1; |
| 240 | my $diff = CORE::length($bx) - CORE::length($by); |
| 241 | if ($diff > 0) |
| 242 | { |
| 243 | $by .= $yy x $diff; |
| 244 | } |
| 245 | elsif ($diff < 0) |
| 246 | { |
| 247 | $bx .= $xx x abs($diff); |
| 248 | } |
| 249 | |
| 250 | # xor the strings together |
| 251 | my $r = $bx ^ $by; |
| 252 | |
| 253 | # and reverse the result again |
| 254 | $bx = reverse $r; |
| 255 | |
| 256 | # one of $x or $y was negative, so need to flip bits in the result |
| 257 | # in both cases (one or two of them negative, or both positive) we need |
| 258 | # to get the characters back. |
| 259 | if ($sign == 1) |
| 260 | { |
| 261 | $bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/0123456789abcdef/; |
| 262 | } |
| 263 | else |
| 264 | { |
| 265 | $bx =~ tr/\x0f\x0e\x0d\x0c\x0b\x0a\x09\x08\x07\x06\x05\x04\x03\x02\x01\x00/fedcba9876543210/; |
| 266 | } |
| 267 | |
| 268 | # leading zeros will be stripped by _from_hex() |
| 269 | $bx = '0x' . $bx; |
| 270 | $x->{value} = $CALC_EMU->_from_hex( $bx ); |
| 271 | |
| 272 | # calculate sign of result |
| 273 | $x->{sign} = '+'; |
| 274 | $x->{sign} = '-' if $sx != $sy && !$x->is_zero(); |
| 275 | |
| 276 | $x->bdec() if $sign == 1; |
| 277 | |
| 278 | $x->round(@r); |
| 279 | } |
| 280 | |
| 281 | ############################################################################## |
| 282 | ############################################################################## |
| 283 | |
| 284 | 1; |
| 285 | __END__ |
| 286 | |
| 287 | =head1 NAME |
| 288 | |
| 289 | Math::BigInt::CalcEmu - Emulate low-level math with BigInt code |
| 290 | |
| 291 | =head1 SYNOPSIS |
| 292 | |
| 293 | use Math::BigInt::CalcEmu; |
| 294 | |
| 295 | =head1 DESCRIPTION |
| 296 | |
| 297 | Contains routines that emulate low-level math functions in BigInt, e.g. |
| 298 | optional routines the low-level math package does not provide on it's own. |
| 299 | |
| 300 | Will be loaded on demand and called automatically by BigInt. |
| 301 | |
| 302 | Stuff here is really low-priority to optimize, since it is far better to |
| 303 | implement the operation in the low-level math libary directly, possible even |
| 304 | using a call to the native lib. |
| 305 | |
| 306 | =head1 METHODS |
| 307 | |
| 308 | =head2 __emu_bxor |
| 309 | |
| 310 | =head2 __emu_band |
| 311 | |
| 312 | =head2 __emu_bior |
| 313 | |
| 314 | =head1 LICENSE |
| 315 | |
| 316 | This program is free software; you may redistribute it and/or modify it under |
| 317 | the same terms as Perl itself. |
| 318 | |
| 319 | =head1 AUTHORS |
| 320 | |
| 321 | (c) Tels http://bloodgate.com 2003, 2004 - based on BigInt code by |
| 322 | Tels from 2001-2003. |
| 323 | |
| 324 | =head1 SEE ALSO |
| 325 | |
| 326 | L<Math::BigInt>, L<Math::BigFloat>, L<Math::BigInt::BitVect>, |
| 327 | L<Math::BigInt::GMP> and L<Math::BigInt::Pari>. |
| 328 | |
| 329 | =cut |