| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 |  | 
|  | 2 | /* | 
|  | 3 | =============================================================================== | 
|  | 4 |  | 
|  | 5 | This C source fragment is part of the SoftFloat IEC/IEEE Floating-point | 
|  | 6 | Arithmetic Package, Release 2. | 
|  | 7 |  | 
|  | 8 | Written by John R. Hauser.  This work was made possible in part by the | 
|  | 9 | International Computer Science Institute, located at Suite 600, 1947 Center | 
|  | 10 | Street, Berkeley, California 94704.  Funding was partially provided by the | 
|  | 11 | National Science Foundation under grant MIP-9311980.  The original version | 
|  | 12 | of this code was written as part of a project to build a fixed-point vector | 
|  | 13 | processor in collaboration with the University of California at Berkeley, | 
|  | 14 | overseen by Profs. Nelson Morgan and John Wawrzynek.  More information | 
|  | 15 | is available through the web page `http://HTTP.CS.Berkeley.EDU/~jhauser/ | 
|  | 16 | arithmetic/softfloat.html'. | 
|  | 17 |  | 
|  | 18 | THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort | 
|  | 19 | has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT | 
|  | 20 | TIMES RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO | 
|  | 21 | PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY | 
|  | 22 | AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. | 
|  | 23 |  | 
|  | 24 | Derivative works are acceptable, even for commercial purposes, so long as | 
|  | 25 | (1) they include prominent notice that the work is derivative, and (2) they | 
|  | 26 | include prominent notice akin to these three paragraphs for those parts of | 
|  | 27 | this code that are retained. | 
|  | 28 |  | 
|  | 29 | =============================================================================== | 
|  | 30 | */ | 
|  | 31 |  | 
|  | 32 | /* | 
|  | 33 | ------------------------------------------------------------------------------- | 
|  | 34 | Shifts `a' right by the number of bits given in `count'.  If any nonzero | 
|  | 35 | bits are shifted off, they are ``jammed'' into the least significant bit of | 
|  | 36 | the result by setting the least significant bit to 1.  The value of `count' | 
|  | 37 | can be arbitrarily large; in particular, if `count' is greater than 32, the | 
|  | 38 | result will be either 0 or 1, depending on whether `a' is zero or nonzero. | 
|  | 39 | The result is stored in the location pointed to by `zPtr'. | 
|  | 40 | ------------------------------------------------------------------------------- | 
|  | 41 | */ | 
|  | 42 | INLINE void shift32RightJamming( bits32 a, int16 count, bits32 *zPtr ) | 
|  | 43 | { | 
|  | 44 | bits32 z; | 
|  | 45 | if ( count == 0 ) { | 
|  | 46 | z = a; | 
|  | 47 | } | 
|  | 48 | else if ( count < 32 ) { | 
|  | 49 | z = ( a>>count ) | ( ( a<<( ( - count ) & 31 ) ) != 0 ); | 
|  | 50 | } | 
|  | 51 | else { | 
|  | 52 | z = ( a != 0 ); | 
|  | 53 | } | 
|  | 54 | *zPtr = z; | 
|  | 55 | } | 
|  | 56 |  | 
|  | 57 | /* | 
|  | 58 | ------------------------------------------------------------------------------- | 
|  | 59 | Shifts `a' right by the number of bits given in `count'.  If any nonzero | 
|  | 60 | bits are shifted off, they are ``jammed'' into the least significant bit of | 
|  | 61 | the result by setting the least significant bit to 1.  The value of `count' | 
|  | 62 | can be arbitrarily large; in particular, if `count' is greater than 64, the | 
|  | 63 | result will be either 0 or 1, depending on whether `a' is zero or nonzero. | 
|  | 64 | The result is stored in the location pointed to by `zPtr'. | 
|  | 65 | ------------------------------------------------------------------------------- | 
|  | 66 | */ | 
|  | 67 | INLINE void shift64RightJamming( bits64 a, int16 count, bits64 *zPtr ) | 
|  | 68 | { | 
|  | 69 | bits64 z; | 
|  | 70 |  | 
|  | 71 | __asm__("@shift64RightJamming -- start"); | 
|  | 72 | if ( count == 0 ) { | 
|  | 73 | z = a; | 
|  | 74 | } | 
|  | 75 | else if ( count < 64 ) { | 
|  | 76 | z = ( a>>count ) | ( ( a<<( ( - count ) & 63 ) ) != 0 ); | 
|  | 77 | } | 
|  | 78 | else { | 
|  | 79 | z = ( a != 0 ); | 
|  | 80 | } | 
|  | 81 | __asm__("@shift64RightJamming -- end"); | 
|  | 82 | *zPtr = z; | 
|  | 83 | } | 
|  | 84 |  | 
|  | 85 | /* | 
|  | 86 | ------------------------------------------------------------------------------- | 
|  | 87 | Shifts the 128-bit value formed by concatenating `a0' and `a1' right by 64 | 
|  | 88 | _plus_ the number of bits given in `count'.  The shifted result is at most | 
|  | 89 | 64 nonzero bits; this is stored at the location pointed to by `z0Ptr'.  The | 
|  | 90 | bits shifted off form a second 64-bit result as follows:  The _last_ bit | 
|  | 91 | shifted off is the most-significant bit of the extra result, and the other | 
|  | 92 | 63 bits of the extra result are all zero if and only if _all_but_the_last_ | 
|  | 93 | bits shifted off were all zero.  This extra result is stored in the location | 
|  | 94 | pointed to by `z1Ptr'.  The value of `count' can be arbitrarily large. | 
|  | 95 | (This routine makes more sense if `a0' and `a1' are considered to form a | 
|  | 96 | fixed-point value with binary point between `a0' and `a1'.  This fixed-point | 
|  | 97 | value is shifted right by the number of bits given in `count', and the | 
|  | 98 | integer part of the result is returned at the location pointed to by | 
|  | 99 | `z0Ptr'.  The fractional part of the result may be slightly corrupted as | 
|  | 100 | described above, and is returned at the location pointed to by `z1Ptr'.) | 
|  | 101 | ------------------------------------------------------------------------------- | 
|  | 102 | */ | 
|  | 103 | INLINE void | 
|  | 104 | shift64ExtraRightJamming( | 
|  | 105 | bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) | 
|  | 106 | { | 
|  | 107 | bits64 z0, z1; | 
|  | 108 | int8 negCount = ( - count ) & 63; | 
|  | 109 |  | 
|  | 110 | if ( count == 0 ) { | 
|  | 111 | z1 = a1; | 
|  | 112 | z0 = a0; | 
|  | 113 | } | 
|  | 114 | else if ( count < 64 ) { | 
|  | 115 | z1 = ( a0<<negCount ) | ( a1 != 0 ); | 
|  | 116 | z0 = a0>>count; | 
|  | 117 | } | 
|  | 118 | else { | 
|  | 119 | if ( count == 64 ) { | 
|  | 120 | z1 = a0 | ( a1 != 0 ); | 
|  | 121 | } | 
|  | 122 | else { | 
|  | 123 | z1 = ( ( a0 | a1 ) != 0 ); | 
|  | 124 | } | 
|  | 125 | z0 = 0; | 
|  | 126 | } | 
|  | 127 | *z1Ptr = z1; | 
|  | 128 | *z0Ptr = z0; | 
|  | 129 |  | 
|  | 130 | } | 
|  | 131 |  | 
|  | 132 | /* | 
|  | 133 | ------------------------------------------------------------------------------- | 
|  | 134 | Shifts the 128-bit value formed by concatenating `a0' and `a1' right by the | 
|  | 135 | number of bits given in `count'.  Any bits shifted off are lost.  The value | 
|  | 136 | of `count' can be arbitrarily large; in particular, if `count' is greater | 
|  | 137 | than 128, the result will be 0.  The result is broken into two 64-bit pieces | 
|  | 138 | which are stored at the locations pointed to by `z0Ptr' and `z1Ptr'. | 
|  | 139 | ------------------------------------------------------------------------------- | 
|  | 140 | */ | 
|  | 141 | INLINE void | 
|  | 142 | shift128Right( | 
|  | 143 | bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) | 
|  | 144 | { | 
|  | 145 | bits64 z0, z1; | 
|  | 146 | int8 negCount = ( - count ) & 63; | 
|  | 147 |  | 
|  | 148 | if ( count == 0 ) { | 
|  | 149 | z1 = a1; | 
|  | 150 | z0 = a0; | 
|  | 151 | } | 
|  | 152 | else if ( count < 64 ) { | 
|  | 153 | z1 = ( a0<<negCount ) | ( a1>>count ); | 
|  | 154 | z0 = a0>>count; | 
|  | 155 | } | 
|  | 156 | else { | 
|  | 157 | z1 = ( count < 64 ) ? ( a0>>( count & 63 ) ) : 0; | 
|  | 158 | z0 = 0; | 
|  | 159 | } | 
|  | 160 | *z1Ptr = z1; | 
|  | 161 | *z0Ptr = z0; | 
|  | 162 |  | 
|  | 163 | } | 
|  | 164 |  | 
|  | 165 | /* | 
|  | 166 | ------------------------------------------------------------------------------- | 
|  | 167 | Shifts the 128-bit value formed by concatenating `a0' and `a1' right by the | 
|  | 168 | number of bits given in `count'.  If any nonzero bits are shifted off, they | 
|  | 169 | are ``jammed'' into the least significant bit of the result by setting the | 
|  | 170 | least significant bit to 1.  The value of `count' can be arbitrarily large; | 
|  | 171 | in particular, if `count' is greater than 128, the result will be either 0 | 
|  | 172 | or 1, depending on whether the concatenation of `a0' and `a1' is zero or | 
|  | 173 | nonzero.  The result is broken into two 64-bit pieces which are stored at | 
|  | 174 | the locations pointed to by `z0Ptr' and `z1Ptr'. | 
|  | 175 | ------------------------------------------------------------------------------- | 
|  | 176 | */ | 
|  | 177 | INLINE void | 
|  | 178 | shift128RightJamming( | 
|  | 179 | bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) | 
|  | 180 | { | 
|  | 181 | bits64 z0, z1; | 
|  | 182 | int8 negCount = ( - count ) & 63; | 
|  | 183 |  | 
|  | 184 | if ( count == 0 ) { | 
|  | 185 | z1 = a1; | 
|  | 186 | z0 = a0; | 
|  | 187 | } | 
|  | 188 | else if ( count < 64 ) { | 
|  | 189 | z1 = ( a0<<negCount ) | ( a1>>count ) | ( ( a1<<negCount ) != 0 ); | 
|  | 190 | z0 = a0>>count; | 
|  | 191 | } | 
|  | 192 | else { | 
|  | 193 | if ( count == 64 ) { | 
|  | 194 | z1 = a0 | ( a1 != 0 ); | 
|  | 195 | } | 
|  | 196 | else if ( count < 128 ) { | 
|  | 197 | z1 = ( a0>>( count & 63 ) ) | ( ( ( a0<<negCount ) | a1 ) != 0 ); | 
|  | 198 | } | 
|  | 199 | else { | 
|  | 200 | z1 = ( ( a0 | a1 ) != 0 ); | 
|  | 201 | } | 
|  | 202 | z0 = 0; | 
|  | 203 | } | 
|  | 204 | *z1Ptr = z1; | 
|  | 205 | *z0Ptr = z0; | 
|  | 206 |  | 
|  | 207 | } | 
|  | 208 |  | 
|  | 209 | /* | 
|  | 210 | ------------------------------------------------------------------------------- | 
|  | 211 | Shifts the 192-bit value formed by concatenating `a0', `a1', and `a2' right | 
|  | 212 | by 64 _plus_ the number of bits given in `count'.  The shifted result is | 
|  | 213 | at most 128 nonzero bits; these are broken into two 64-bit pieces which are | 
|  | 214 | stored at the locations pointed to by `z0Ptr' and `z1Ptr'.  The bits shifted | 
|  | 215 | off form a third 64-bit result as follows:  The _last_ bit shifted off is | 
|  | 216 | the most-significant bit of the extra result, and the other 63 bits of the | 
|  | 217 | extra result are all zero if and only if _all_but_the_last_ bits shifted off | 
|  | 218 | were all zero.  This extra result is stored in the location pointed to by | 
|  | 219 | `z2Ptr'.  The value of `count' can be arbitrarily large. | 
|  | 220 | (This routine makes more sense if `a0', `a1', and `a2' are considered | 
|  | 221 | to form a fixed-point value with binary point between `a1' and `a2'.  This | 
|  | 222 | fixed-point value is shifted right by the number of bits given in `count', | 
|  | 223 | and the integer part of the result is returned at the locations pointed to | 
|  | 224 | by `z0Ptr' and `z1Ptr'.  The fractional part of the result may be slightly | 
|  | 225 | corrupted as described above, and is returned at the location pointed to by | 
|  | 226 | `z2Ptr'.) | 
|  | 227 | ------------------------------------------------------------------------------- | 
|  | 228 | */ | 
|  | 229 | INLINE void | 
|  | 230 | shift128ExtraRightJamming( | 
|  | 231 | bits64 a0, | 
|  | 232 | bits64 a1, | 
|  | 233 | bits64 a2, | 
|  | 234 | int16 count, | 
|  | 235 | bits64 *z0Ptr, | 
|  | 236 | bits64 *z1Ptr, | 
|  | 237 | bits64 *z2Ptr | 
|  | 238 | ) | 
|  | 239 | { | 
|  | 240 | bits64 z0, z1, z2; | 
|  | 241 | int8 negCount = ( - count ) & 63; | 
|  | 242 |  | 
|  | 243 | if ( count == 0 ) { | 
|  | 244 | z2 = a2; | 
|  | 245 | z1 = a1; | 
|  | 246 | z0 = a0; | 
|  | 247 | } | 
|  | 248 | else { | 
|  | 249 | if ( count < 64 ) { | 
|  | 250 | z2 = a1<<negCount; | 
|  | 251 | z1 = ( a0<<negCount ) | ( a1>>count ); | 
|  | 252 | z0 = a0>>count; | 
|  | 253 | } | 
|  | 254 | else { | 
|  | 255 | if ( count == 64 ) { | 
|  | 256 | z2 = a1; | 
|  | 257 | z1 = a0; | 
|  | 258 | } | 
|  | 259 | else { | 
|  | 260 | a2 |= a1; | 
|  | 261 | if ( count < 128 ) { | 
|  | 262 | z2 = a0<<negCount; | 
|  | 263 | z1 = a0>>( count & 63 ); | 
|  | 264 | } | 
|  | 265 | else { | 
|  | 266 | z2 = ( count == 128 ) ? a0 : ( a0 != 0 ); | 
|  | 267 | z1 = 0; | 
|  | 268 | } | 
|  | 269 | } | 
|  | 270 | z0 = 0; | 
|  | 271 | } | 
|  | 272 | z2 |= ( a2 != 0 ); | 
|  | 273 | } | 
|  | 274 | *z2Ptr = z2; | 
|  | 275 | *z1Ptr = z1; | 
|  | 276 | *z0Ptr = z0; | 
|  | 277 |  | 
|  | 278 | } | 
|  | 279 |  | 
|  | 280 | /* | 
|  | 281 | ------------------------------------------------------------------------------- | 
|  | 282 | Shifts the 128-bit value formed by concatenating `a0' and `a1' left by the | 
|  | 283 | number of bits given in `count'.  Any bits shifted off are lost.  The value | 
|  | 284 | of `count' must be less than 64.  The result is broken into two 64-bit | 
|  | 285 | pieces which are stored at the locations pointed to by `z0Ptr' and `z1Ptr'. | 
|  | 286 | ------------------------------------------------------------------------------- | 
|  | 287 | */ | 
|  | 288 | INLINE void | 
|  | 289 | shortShift128Left( | 
|  | 290 | bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) | 
|  | 291 | { | 
|  | 292 |  | 
|  | 293 | *z1Ptr = a1<<count; | 
|  | 294 | *z0Ptr = | 
|  | 295 | ( count == 0 ) ? a0 : ( a0<<count ) | ( a1>>( ( - count ) & 63 ) ); | 
|  | 296 |  | 
|  | 297 | } | 
|  | 298 |  | 
|  | 299 | /* | 
|  | 300 | ------------------------------------------------------------------------------- | 
|  | 301 | Shifts the 192-bit value formed by concatenating `a0', `a1', and `a2' left | 
|  | 302 | by the number of bits given in `count'.  Any bits shifted off are lost. | 
|  | 303 | The value of `count' must be less than 64.  The result is broken into three | 
|  | 304 | 64-bit pieces which are stored at the locations pointed to by `z0Ptr', | 
|  | 305 | `z1Ptr', and `z2Ptr'. | 
|  | 306 | ------------------------------------------------------------------------------- | 
|  | 307 | */ | 
|  | 308 | INLINE void | 
|  | 309 | shortShift192Left( | 
|  | 310 | bits64 a0, | 
|  | 311 | bits64 a1, | 
|  | 312 | bits64 a2, | 
|  | 313 | int16 count, | 
|  | 314 | bits64 *z0Ptr, | 
|  | 315 | bits64 *z1Ptr, | 
|  | 316 | bits64 *z2Ptr | 
|  | 317 | ) | 
|  | 318 | { | 
|  | 319 | bits64 z0, z1, z2; | 
|  | 320 | int8 negCount; | 
|  | 321 |  | 
|  | 322 | z2 = a2<<count; | 
|  | 323 | z1 = a1<<count; | 
|  | 324 | z0 = a0<<count; | 
|  | 325 | if ( 0 < count ) { | 
|  | 326 | negCount = ( ( - count ) & 63 ); | 
|  | 327 | z1 |= a2>>negCount; | 
|  | 328 | z0 |= a1>>negCount; | 
|  | 329 | } | 
|  | 330 | *z2Ptr = z2; | 
|  | 331 | *z1Ptr = z1; | 
|  | 332 | *z0Ptr = z0; | 
|  | 333 |  | 
|  | 334 | } | 
|  | 335 |  | 
|  | 336 | /* | 
|  | 337 | ------------------------------------------------------------------------------- | 
|  | 338 | Adds the 128-bit value formed by concatenating `a0' and `a1' to the 128-bit | 
|  | 339 | value formed by concatenating `b0' and `b1'.  Addition is modulo 2^128, so | 
|  | 340 | any carry out is lost.  The result is broken into two 64-bit pieces which | 
|  | 341 | are stored at the locations pointed to by `z0Ptr' and `z1Ptr'. | 
|  | 342 | ------------------------------------------------------------------------------- | 
|  | 343 | */ | 
|  | 344 | INLINE void | 
|  | 345 | add128( | 
|  | 346 | bits64 a0, bits64 a1, bits64 b0, bits64 b1, bits64 *z0Ptr, bits64 *z1Ptr ) | 
|  | 347 | { | 
|  | 348 | bits64 z1; | 
|  | 349 |  | 
|  | 350 | z1 = a1 + b1; | 
|  | 351 | *z1Ptr = z1; | 
|  | 352 | *z0Ptr = a0 + b0 + ( z1 < a1 ); | 
|  | 353 |  | 
|  | 354 | } | 
|  | 355 |  | 
|  | 356 | /* | 
|  | 357 | ------------------------------------------------------------------------------- | 
|  | 358 | Adds the 192-bit value formed by concatenating `a0', `a1', and `a2' to the | 
|  | 359 | 192-bit value formed by concatenating `b0', `b1', and `b2'.  Addition is | 
|  | 360 | modulo 2^192, so any carry out is lost.  The result is broken into three | 
|  | 361 | 64-bit pieces which are stored at the locations pointed to by `z0Ptr', | 
|  | 362 | `z1Ptr', and `z2Ptr'. | 
|  | 363 | ------------------------------------------------------------------------------- | 
|  | 364 | */ | 
|  | 365 | INLINE void | 
|  | 366 | add192( | 
|  | 367 | bits64 a0, | 
|  | 368 | bits64 a1, | 
|  | 369 | bits64 a2, | 
|  | 370 | bits64 b0, | 
|  | 371 | bits64 b1, | 
|  | 372 | bits64 b2, | 
|  | 373 | bits64 *z0Ptr, | 
|  | 374 | bits64 *z1Ptr, | 
|  | 375 | bits64 *z2Ptr | 
|  | 376 | ) | 
|  | 377 | { | 
|  | 378 | bits64 z0, z1, z2; | 
|  | 379 | int8 carry0, carry1; | 
|  | 380 |  | 
|  | 381 | z2 = a2 + b2; | 
|  | 382 | carry1 = ( z2 < a2 ); | 
|  | 383 | z1 = a1 + b1; | 
|  | 384 | carry0 = ( z1 < a1 ); | 
|  | 385 | z0 = a0 + b0; | 
|  | 386 | z1 += carry1; | 
|  | 387 | z0 += ( z1 < carry1 ); | 
|  | 388 | z0 += carry0; | 
|  | 389 | *z2Ptr = z2; | 
|  | 390 | *z1Ptr = z1; | 
|  | 391 | *z0Ptr = z0; | 
|  | 392 |  | 
|  | 393 | } | 
|  | 394 |  | 
|  | 395 | /* | 
|  | 396 | ------------------------------------------------------------------------------- | 
|  | 397 | Subtracts the 128-bit value formed by concatenating `b0' and `b1' from the | 
|  | 398 | 128-bit value formed by concatenating `a0' and `a1'.  Subtraction is modulo | 
|  | 399 | 2^128, so any borrow out (carry out) is lost.  The result is broken into two | 
|  | 400 | 64-bit pieces which are stored at the locations pointed to by `z0Ptr' and | 
|  | 401 | `z1Ptr'. | 
|  | 402 | ------------------------------------------------------------------------------- | 
|  | 403 | */ | 
|  | 404 | INLINE void | 
|  | 405 | sub128( | 
|  | 406 | bits64 a0, bits64 a1, bits64 b0, bits64 b1, bits64 *z0Ptr, bits64 *z1Ptr ) | 
|  | 407 | { | 
|  | 408 |  | 
|  | 409 | *z1Ptr = a1 - b1; | 
|  | 410 | *z0Ptr = a0 - b0 - ( a1 < b1 ); | 
|  | 411 |  | 
|  | 412 | } | 
|  | 413 |  | 
|  | 414 | /* | 
|  | 415 | ------------------------------------------------------------------------------- | 
|  | 416 | Subtracts the 192-bit value formed by concatenating `b0', `b1', and `b2' | 
|  | 417 | from the 192-bit value formed by concatenating `a0', `a1', and `a2'. | 
|  | 418 | Subtraction is modulo 2^192, so any borrow out (carry out) is lost.  The | 
|  | 419 | result is broken into three 64-bit pieces which are stored at the locations | 
|  | 420 | pointed to by `z0Ptr', `z1Ptr', and `z2Ptr'. | 
|  | 421 | ------------------------------------------------------------------------------- | 
|  | 422 | */ | 
|  | 423 | INLINE void | 
|  | 424 | sub192( | 
|  | 425 | bits64 a0, | 
|  | 426 | bits64 a1, | 
|  | 427 | bits64 a2, | 
|  | 428 | bits64 b0, | 
|  | 429 | bits64 b1, | 
|  | 430 | bits64 b2, | 
|  | 431 | bits64 *z0Ptr, | 
|  | 432 | bits64 *z1Ptr, | 
|  | 433 | bits64 *z2Ptr | 
|  | 434 | ) | 
|  | 435 | { | 
|  | 436 | bits64 z0, z1, z2; | 
|  | 437 | int8 borrow0, borrow1; | 
|  | 438 |  | 
|  | 439 | z2 = a2 - b2; | 
|  | 440 | borrow1 = ( a2 < b2 ); | 
|  | 441 | z1 = a1 - b1; | 
|  | 442 | borrow0 = ( a1 < b1 ); | 
|  | 443 | z0 = a0 - b0; | 
|  | 444 | z0 -= ( z1 < borrow1 ); | 
|  | 445 | z1 -= borrow1; | 
|  | 446 | z0 -= borrow0; | 
|  | 447 | *z2Ptr = z2; | 
|  | 448 | *z1Ptr = z1; | 
|  | 449 | *z0Ptr = z0; | 
|  | 450 |  | 
|  | 451 | } | 
|  | 452 |  | 
|  | 453 | /* | 
|  | 454 | ------------------------------------------------------------------------------- | 
|  | 455 | Multiplies `a' by `b' to obtain a 128-bit product.  The product is broken | 
|  | 456 | into two 64-bit pieces which are stored at the locations pointed to by | 
|  | 457 | `z0Ptr' and `z1Ptr'. | 
|  | 458 | ------------------------------------------------------------------------------- | 
|  | 459 | */ | 
|  | 460 | INLINE void mul64To128( bits64 a, bits64 b, bits64 *z0Ptr, bits64 *z1Ptr ) | 
|  | 461 | { | 
|  | 462 | bits32 aHigh, aLow, bHigh, bLow; | 
|  | 463 | bits64 z0, zMiddleA, zMiddleB, z1; | 
|  | 464 |  | 
|  | 465 | aLow = a; | 
|  | 466 | aHigh = a>>32; | 
|  | 467 | bLow = b; | 
|  | 468 | bHigh = b>>32; | 
|  | 469 | z1 = ( (bits64) aLow ) * bLow; | 
|  | 470 | zMiddleA = ( (bits64) aLow ) * bHigh; | 
|  | 471 | zMiddleB = ( (bits64) aHigh ) * bLow; | 
|  | 472 | z0 = ( (bits64) aHigh ) * bHigh; | 
|  | 473 | zMiddleA += zMiddleB; | 
|  | 474 | z0 += ( ( (bits64) ( zMiddleA < zMiddleB ) )<<32 ) + ( zMiddleA>>32 ); | 
|  | 475 | zMiddleA <<= 32; | 
|  | 476 | z1 += zMiddleA; | 
|  | 477 | z0 += ( z1 < zMiddleA ); | 
|  | 478 | *z1Ptr = z1; | 
|  | 479 | *z0Ptr = z0; | 
|  | 480 |  | 
|  | 481 | } | 
|  | 482 |  | 
|  | 483 | /* | 
|  | 484 | ------------------------------------------------------------------------------- | 
|  | 485 | Multiplies the 128-bit value formed by concatenating `a0' and `a1' by `b' to | 
|  | 486 | obtain a 192-bit product.  The product is broken into three 64-bit pieces | 
|  | 487 | which are stored at the locations pointed to by `z0Ptr', `z1Ptr', and | 
|  | 488 | `z2Ptr'. | 
|  | 489 | ------------------------------------------------------------------------------- | 
|  | 490 | */ | 
|  | 491 | INLINE void | 
|  | 492 | mul128By64To192( | 
|  | 493 | bits64 a0, | 
|  | 494 | bits64 a1, | 
|  | 495 | bits64 b, | 
|  | 496 | bits64 *z0Ptr, | 
|  | 497 | bits64 *z1Ptr, | 
|  | 498 | bits64 *z2Ptr | 
|  | 499 | ) | 
|  | 500 | { | 
|  | 501 | bits64 z0, z1, z2, more1; | 
|  | 502 |  | 
|  | 503 | mul64To128( a1, b, &z1, &z2 ); | 
|  | 504 | mul64To128( a0, b, &z0, &more1 ); | 
|  | 505 | add128( z0, more1, 0, z1, &z0, &z1 ); | 
|  | 506 | *z2Ptr = z2; | 
|  | 507 | *z1Ptr = z1; | 
|  | 508 | *z0Ptr = z0; | 
|  | 509 |  | 
|  | 510 | } | 
|  | 511 |  | 
|  | 512 | /* | 
|  | 513 | ------------------------------------------------------------------------------- | 
|  | 514 | Multiplies the 128-bit value formed by concatenating `a0' and `a1' to the | 
|  | 515 | 128-bit value formed by concatenating `b0' and `b1' to obtain a 256-bit | 
|  | 516 | product.  The product is broken into four 64-bit pieces which are stored at | 
|  | 517 | the locations pointed to by `z0Ptr', `z1Ptr', `z2Ptr', and `z3Ptr'. | 
|  | 518 | ------------------------------------------------------------------------------- | 
|  | 519 | */ | 
|  | 520 | INLINE void | 
|  | 521 | mul128To256( | 
|  | 522 | bits64 a0, | 
|  | 523 | bits64 a1, | 
|  | 524 | bits64 b0, | 
|  | 525 | bits64 b1, | 
|  | 526 | bits64 *z0Ptr, | 
|  | 527 | bits64 *z1Ptr, | 
|  | 528 | bits64 *z2Ptr, | 
|  | 529 | bits64 *z3Ptr | 
|  | 530 | ) | 
|  | 531 | { | 
|  | 532 | bits64 z0, z1, z2, z3; | 
|  | 533 | bits64 more1, more2; | 
|  | 534 |  | 
|  | 535 | mul64To128( a1, b1, &z2, &z3 ); | 
|  | 536 | mul64To128( a1, b0, &z1, &more2 ); | 
|  | 537 | add128( z1, more2, 0, z2, &z1, &z2 ); | 
|  | 538 | mul64To128( a0, b0, &z0, &more1 ); | 
|  | 539 | add128( z0, more1, 0, z1, &z0, &z1 ); | 
|  | 540 | mul64To128( a0, b1, &more1, &more2 ); | 
|  | 541 | add128( more1, more2, 0, z2, &more1, &z2 ); | 
|  | 542 | add128( z0, z1, 0, more1, &z0, &z1 ); | 
|  | 543 | *z3Ptr = z3; | 
|  | 544 | *z2Ptr = z2; | 
|  | 545 | *z1Ptr = z1; | 
|  | 546 | *z0Ptr = z0; | 
|  | 547 |  | 
|  | 548 | } | 
|  | 549 |  | 
|  | 550 | /* | 
|  | 551 | ------------------------------------------------------------------------------- | 
|  | 552 | Returns an approximation to the 64-bit integer quotient obtained by dividing | 
|  | 553 | `b' into the 128-bit value formed by concatenating `a0' and `a1'.  The | 
|  | 554 | divisor `b' must be at least 2^63.  If q is the exact quotient truncated | 
|  | 555 | toward zero, the approximation returned lies between q and q + 2 inclusive. | 
|  | 556 | If the exact quotient q is larger than 64 bits, the maximum positive 64-bit | 
|  | 557 | unsigned integer is returned. | 
|  | 558 | ------------------------------------------------------------------------------- | 
|  | 559 | */ | 
|  | 560 | static bits64 estimateDiv128To64( bits64 a0, bits64 a1, bits64 b ) | 
|  | 561 | { | 
|  | 562 | bits64 b0, b1; | 
|  | 563 | bits64 rem0, rem1, term0, term1; | 
|  | 564 | bits64 z; | 
|  | 565 | if ( b <= a0 ) return LIT64( 0xFFFFFFFFFFFFFFFF ); | 
| Nicolas Pitre | c1241c4c | 2005-06-23 21:56:46 +0100 | [diff] [blame] | 566 | b0 = b>>32;  /* hence b0 is 32 bits wide now */ | 
|  | 567 | if ( b0<<32 <= a0 ) { | 
|  | 568 | z = LIT64( 0xFFFFFFFF00000000 ); | 
|  | 569 | }  else { | 
|  | 570 | z = a0; | 
|  | 571 | do_div( z, b0 ); | 
|  | 572 | z <<= 32; | 
|  | 573 | } | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | mul64To128( b, z, &term0, &term1 ); | 
|  | 575 | sub128( a0, a1, term0, term1, &rem0, &rem1 ); | 
|  | 576 | while ( ( (sbits64) rem0 ) < 0 ) { | 
|  | 577 | z -= LIT64( 0x100000000 ); | 
|  | 578 | b1 = b<<32; | 
|  | 579 | add128( rem0, rem1, b0, b1, &rem0, &rem1 ); | 
|  | 580 | } | 
|  | 581 | rem0 = ( rem0<<32 ) | ( rem1>>32 ); | 
| Nicolas Pitre | c1241c4c | 2005-06-23 21:56:46 +0100 | [diff] [blame] | 582 | if ( b0<<32 <= rem0 ) { | 
|  | 583 | z |= 0xFFFFFFFF; | 
|  | 584 | } else { | 
|  | 585 | do_div( rem0, b0 ); | 
|  | 586 | z |= rem0; | 
|  | 587 | } | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 588 | return z; | 
|  | 589 |  | 
|  | 590 | } | 
|  | 591 |  | 
|  | 592 | /* | 
|  | 593 | ------------------------------------------------------------------------------- | 
|  | 594 | Returns an approximation to the square root of the 32-bit significand given | 
|  | 595 | by `a'.  Considered as an integer, `a' must be at least 2^31.  If bit 0 of | 
|  | 596 | `aExp' (the least significant bit) is 1, the integer returned approximates | 
|  | 597 | 2^31*sqrt(`a'/2^31), where `a' is considered an integer.  If bit 0 of `aExp' | 
|  | 598 | is 0, the integer returned approximates 2^31*sqrt(`a'/2^30).  In either | 
|  | 599 | case, the approximation returned lies strictly within +/-2 of the exact | 
|  | 600 | value. | 
|  | 601 | ------------------------------------------------------------------------------- | 
|  | 602 | */ | 
|  | 603 | static bits32 estimateSqrt32( int16 aExp, bits32 a ) | 
|  | 604 | { | 
|  | 605 | static const bits16 sqrtOddAdjustments[] = { | 
|  | 606 | 0x0004, 0x0022, 0x005D, 0x00B1, 0x011D, 0x019F, 0x0236, 0x02E0, | 
|  | 607 | 0x039C, 0x0468, 0x0545, 0x0631, 0x072B, 0x0832, 0x0946, 0x0A67 | 
|  | 608 | }; | 
|  | 609 | static const bits16 sqrtEvenAdjustments[] = { | 
|  | 610 | 0x0A2D, 0x08AF, 0x075A, 0x0629, 0x051A, 0x0429, 0x0356, 0x029E, | 
|  | 611 | 0x0200, 0x0179, 0x0109, 0x00AF, 0x0068, 0x0034, 0x0012, 0x0002 | 
|  | 612 | }; | 
|  | 613 | int8 index; | 
|  | 614 | bits32 z; | 
| Nicolas Pitre | c1241c4c | 2005-06-23 21:56:46 +0100 | [diff] [blame] | 615 | bits64 A; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 |  | 
|  | 617 | index = ( a>>27 ) & 15; | 
|  | 618 | if ( aExp & 1 ) { | 
|  | 619 | z = 0x4000 + ( a>>17 ) - sqrtOddAdjustments[ index ]; | 
|  | 620 | z = ( ( a / z )<<14 ) + ( z<<15 ); | 
|  | 621 | a >>= 1; | 
|  | 622 | } | 
|  | 623 | else { | 
|  | 624 | z = 0x8000 + ( a>>17 ) - sqrtEvenAdjustments[ index ]; | 
|  | 625 | z = a / z + z; | 
|  | 626 | z = ( 0x20000 <= z ) ? 0xFFFF8000 : ( z<<15 ); | 
|  | 627 | if ( z <= a ) return (bits32) ( ( (sbits32) a )>>1 ); | 
|  | 628 | } | 
| Nicolas Pitre | c1241c4c | 2005-06-23 21:56:46 +0100 | [diff] [blame] | 629 | A = ( (bits64) a )<<31; | 
|  | 630 | do_div( A, z ); | 
|  | 631 | return ( (bits32) A ) + ( z>>1 ); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 |  | 
|  | 633 | } | 
|  | 634 |  | 
|  | 635 | /* | 
|  | 636 | ------------------------------------------------------------------------------- | 
|  | 637 | Returns the number of leading 0 bits before the most-significant 1 bit | 
|  | 638 | of `a'.  If `a' is zero, 32 is returned. | 
|  | 639 | ------------------------------------------------------------------------------- | 
|  | 640 | */ | 
|  | 641 | static int8 countLeadingZeros32( bits32 a ) | 
|  | 642 | { | 
|  | 643 | static const int8 countLeadingZerosHigh[] = { | 
|  | 644 | 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, | 
|  | 645 | 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, | 
|  | 646 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | 
|  | 647 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | 
|  | 648 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | 
|  | 649 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | 
|  | 650 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | 
|  | 651 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | 
|  | 652 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | 
|  | 653 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | 
|  | 654 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | 
|  | 655 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | 
|  | 656 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | 
|  | 657 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | 
|  | 658 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | 
|  | 659 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 | 
|  | 660 | }; | 
|  | 661 | int8 shiftCount; | 
|  | 662 |  | 
|  | 663 | shiftCount = 0; | 
|  | 664 | if ( a < 0x10000 ) { | 
|  | 665 | shiftCount += 16; | 
|  | 666 | a <<= 16; | 
|  | 667 | } | 
|  | 668 | if ( a < 0x1000000 ) { | 
|  | 669 | shiftCount += 8; | 
|  | 670 | a <<= 8; | 
|  | 671 | } | 
|  | 672 | shiftCount += countLeadingZerosHigh[ a>>24 ]; | 
|  | 673 | return shiftCount; | 
|  | 674 |  | 
|  | 675 | } | 
|  | 676 |  | 
|  | 677 | /* | 
|  | 678 | ------------------------------------------------------------------------------- | 
|  | 679 | Returns the number of leading 0 bits before the most-significant 1 bit | 
|  | 680 | of `a'.  If `a' is zero, 64 is returned. | 
|  | 681 | ------------------------------------------------------------------------------- | 
|  | 682 | */ | 
|  | 683 | static int8 countLeadingZeros64( bits64 a ) | 
|  | 684 | { | 
|  | 685 | int8 shiftCount; | 
|  | 686 |  | 
|  | 687 | shiftCount = 0; | 
|  | 688 | if ( a < ( (bits64) 1 )<<32 ) { | 
|  | 689 | shiftCount += 32; | 
|  | 690 | } | 
|  | 691 | else { | 
|  | 692 | a >>= 32; | 
|  | 693 | } | 
|  | 694 | shiftCount += countLeadingZeros32( a ); | 
|  | 695 | return shiftCount; | 
|  | 696 |  | 
|  | 697 | } | 
|  | 698 |  | 
|  | 699 | /* | 
|  | 700 | ------------------------------------------------------------------------------- | 
|  | 701 | Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' | 
|  | 702 | is equal to the 128-bit value formed by concatenating `b0' and `b1'. | 
|  | 703 | Otherwise, returns 0. | 
|  | 704 | ------------------------------------------------------------------------------- | 
|  | 705 | */ | 
|  | 706 | INLINE flag eq128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) | 
|  | 707 | { | 
|  | 708 |  | 
|  | 709 | return ( a0 == b0 ) && ( a1 == b1 ); | 
|  | 710 |  | 
|  | 711 | } | 
|  | 712 |  | 
|  | 713 | /* | 
|  | 714 | ------------------------------------------------------------------------------- | 
|  | 715 | Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' is less | 
|  | 716 | than or equal to the 128-bit value formed by concatenating `b0' and `b1'. | 
|  | 717 | Otherwise, returns 0. | 
|  | 718 | ------------------------------------------------------------------------------- | 
|  | 719 | */ | 
|  | 720 | INLINE flag le128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) | 
|  | 721 | { | 
|  | 722 |  | 
|  | 723 | return ( a0 < b0 ) || ( ( a0 == b0 ) && ( a1 <= b1 ) ); | 
|  | 724 |  | 
|  | 725 | } | 
|  | 726 |  | 
|  | 727 | /* | 
|  | 728 | ------------------------------------------------------------------------------- | 
|  | 729 | Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' is less | 
|  | 730 | than the 128-bit value formed by concatenating `b0' and `b1'.  Otherwise, | 
|  | 731 | returns 0. | 
|  | 732 | ------------------------------------------------------------------------------- | 
|  | 733 | */ | 
|  | 734 | INLINE flag lt128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) | 
|  | 735 | { | 
|  | 736 |  | 
|  | 737 | return ( a0 < b0 ) || ( ( a0 == b0 ) && ( a1 < b1 ) ); | 
|  | 738 |  | 
|  | 739 | } | 
|  | 740 |  | 
|  | 741 | /* | 
|  | 742 | ------------------------------------------------------------------------------- | 
|  | 743 | Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' is | 
|  | 744 | not equal to the 128-bit value formed by concatenating `b0' and `b1'. | 
|  | 745 | Otherwise, returns 0. | 
|  | 746 | ------------------------------------------------------------------------------- | 
|  | 747 | */ | 
|  | 748 | INLINE flag ne128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) | 
|  | 749 | { | 
|  | 750 |  | 
|  | 751 | return ( a0 != b0 ) || ( a1 != b1 ); | 
|  | 752 |  | 
|  | 753 | } | 
|  | 754 |  |