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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 | /*---------------------------------------------------------------------------+ | reg_compare.c | | | | Compare two floating point registers | | | | Copyright (C) 1992,1993,1994,1997 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | | E-mail billm@suburbia.net | | | | | +---------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------+ | compare() is the core FPU_REG comparison function | +---------------------------------------------------------------------------*/ #include "fpu_system.h" #include "exception.h" #include "fpu_emu.h" #include "control_w.h" #include "status_w.h" static int compare(FPU_REG const *b, int tagb) { int diff, exp0, expb; u_char st0_tag; FPU_REG *st0_ptr; FPU_REG x, y; u_char st0_sign, signb = getsign(b); st0_ptr = &st(0); st0_tag = FPU_gettag0(); st0_sign = getsign(st0_ptr); if ( tagb == TAG_Special ) tagb = FPU_Special(b); if ( st0_tag == TAG_Special ) st0_tag = FPU_Special(st0_ptr); if ( ((st0_tag != TAG_Valid) && (st0_tag != TW_Denormal)) || ((tagb != TAG_Valid) && (tagb != TW_Denormal)) ) { if ( st0_tag == TAG_Zero ) { if ( tagb == TAG_Zero ) return COMP_A_eq_B; if ( tagb == TAG_Valid ) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B); if ( tagb == TW_Denormal ) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B) | COMP_Denormal; } else if ( tagb == TAG_Zero ) { if ( st0_tag == TAG_Valid ) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B); if ( st0_tag == TW_Denormal ) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | COMP_Denormal; } if ( st0_tag == TW_Infinity ) { if ( (tagb == TAG_Valid) || (tagb == TAG_Zero) ) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B); else if ( tagb == TW_Denormal ) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | COMP_Denormal; else if ( tagb == TW_Infinity ) { /* The 80486 book says that infinities can be equal! */ return (st0_sign == signb) ? COMP_A_eq_B : ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B); } /* Fall through to the NaN code */ } else if ( tagb == TW_Infinity ) { if ( (st0_tag == TAG_Valid) || (st0_tag == TAG_Zero) ) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B); if ( st0_tag == TW_Denormal ) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B) | COMP_Denormal; /* Fall through to the NaN code */ } /* The only possibility now should be that one of the arguments is a NaN */ if ( (st0_tag == TW_NaN) || (tagb == TW_NaN) ) { int signalling = 0, unsupported = 0; if ( st0_tag == TW_NaN ) { signalling = (st0_ptr->sigh & 0xc0000000) == 0x80000000; unsupported = !((exponent(st0_ptr) == EXP_OVER) && (st0_ptr->sigh & 0x80000000)); } if ( tagb == TW_NaN ) { signalling |= (b->sigh & 0xc0000000) == 0x80000000; unsupported |= !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)); } if ( signalling || unsupported ) return COMP_No_Comp | COMP_SNaN | COMP_NaN; else /* Neither is a signaling NaN */ return COMP_No_Comp | COMP_NaN; } EXCEPTION(EX_Invalid); } if (st0_sign != signb) { return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | ( ((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); } if ( (st0_tag == TW_Denormal) || (tagb == TW_Denormal) ) { FPU_to_exp16(st0_ptr, &x); FPU_to_exp16(b, &y); st0_ptr = &x; b = &y; exp0 = exponent16(st0_ptr); expb = exponent16(b); } else { exp0 = exponent(st0_ptr); expb = exponent(b); } #ifdef PARANOID if (!(st0_ptr->sigh & 0x80000000)) EXCEPTION(EX_Invalid); if (!(b->sigh & 0x80000000)) EXCEPTION(EX_Invalid); #endif PARANOID diff = exp0 - expb; if ( diff == 0 ) { diff = st0_ptr->sigh - b->sigh; /* Works only if ms bits are identical */ if ( diff == 0 ) { diff = st0_ptr->sigl > b->sigl; if ( diff == 0 ) diff = -(st0_ptr->sigl < b->sigl); } } if ( diff > 0 ) { return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | ( ((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); } if ( diff < 0 ) { return ((st0_sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B) | ( ((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); } return COMP_A_eq_B | ( ((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); } /* This function requires that st(0) is not empty */ int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag) { int f, c; c = compare(loaded_data, loaded_tag); if (c & COMP_NaN) { EXCEPTION(EX_Invalid); f = SW_C3 | SW_C2 | SW_C0; } else switch (c & 7) { case COMP_A_lt_B: f = SW_C0; break; case COMP_A_eq_B: f = SW_C3; break; case COMP_A_gt_B: f = 0; break; case COMP_No_Comp: f = SW_C3 | SW_C2 | SW_C0; break; #ifdef PARANOID default: EXCEPTION(EX_INTERNAL|0x121); f = SW_C3 | SW_C2 | SW_C0; break; #endif PARANOID } setcc(f); if (c & COMP_Denormal) { return denormal_operand() < 0; } return 0; } static int compare_st_st(int nr) { int f, c; FPU_REG *st_ptr; if ( !NOT_EMPTY(0) || !NOT_EMPTY(nr) ) { setcc(SW_C3 | SW_C2 | SW_C0); /* Stack fault */ EXCEPTION(EX_StackUnder); return !(control_word & CW_Invalid); } st_ptr = &st(nr); c = compare(st_ptr, FPU_gettagi(nr)); if (c & COMP_NaN) { setcc(SW_C3 | SW_C2 | SW_C0); EXCEPTION(EX_Invalid); return !(control_word & CW_Invalid); } else switch (c & 7) { case COMP_A_lt_B: f = SW_C0; break; case COMP_A_eq_B: f = SW_C3; break; case COMP_A_gt_B: f = 0; break; case COMP_No_Comp: f = SW_C3 | SW_C2 | SW_C0; break; #ifdef PARANOID default: EXCEPTION(EX_INTERNAL|0x122); f = SW_C3 | SW_C2 | SW_C0; break; #endif PARANOID } setcc(f); if (c & COMP_Denormal) { return denormal_operand() < 0; } return 0; } static int compare_u_st_st(int nr) { int f, c; FPU_REG *st_ptr; if ( !NOT_EMPTY(0) || !NOT_EMPTY(nr) ) { setcc(SW_C3 | SW_C2 | SW_C0); /* Stack fault */ EXCEPTION(EX_StackUnder); return !(control_word & CW_Invalid); } st_ptr = &st(nr); c = compare(st_ptr, FPU_gettagi(nr)); if (c & COMP_NaN) { setcc(SW_C3 | SW_C2 | SW_C0); if (c & COMP_SNaN) /* This is the only difference between un-ordered and ordinary comparisons */ { EXCEPTION(EX_Invalid); return !(control_word & CW_Invalid); } return 0; } else switch (c & 7) { case COMP_A_lt_B: f = SW_C0; break; case COMP_A_eq_B: f = SW_C3; break; case COMP_A_gt_B: f = 0; break; case COMP_No_Comp: f = SW_C3 | SW_C2 | SW_C0; break; #ifdef PARANOID default: EXCEPTION(EX_INTERNAL|0x123); f = SW_C3 | SW_C2 | SW_C0; break; #endif PARANOID } setcc(f); if (c & COMP_Denormal) { return denormal_operand() < 0; } return 0; } /*---------------------------------------------------------------------------*/ void fcom_st() { /* fcom st(i) */ compare_st_st(FPU_rm); } void fcompst() { /* fcomp st(i) */ if ( !compare_st_st(FPU_rm) ) FPU_pop(); } void fcompp() { /* fcompp */ if (FPU_rm != 1) { FPU_illegal(); return; } if ( !compare_st_st(1) ) poppop(); } void fucom_() { /* fucom st(i) */ compare_u_st_st(FPU_rm); } void fucomp() { /* fucomp st(i) */ if ( !compare_u_st_st(FPU_rm) ) FPU_pop(); } void fucompp() { /* fucompp */ if (FPU_rm == 1) { if ( !compare_u_st_st(1) ) poppop(); } else FPU_illegal(); } |