1 /* 2 * ARM VFP floating-point operations 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with this library; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/osdep.h" 21 #include "qemu/log.h" 22 #include "cpu.h" 23 #include "exec/helper-proto.h" 24 #include "fpu/softfloat.h" 25 #include "internals.h" 26 27 28 /* VFP support. We follow the convention used for VFP instructions: 29 Single precision routines have a "s" suffix, double precision a 30 "d" suffix. */ 31 32 /* Convert host exception flags to vfp form. */ 33 static inline int vfp_exceptbits_from_host(int host_bits) 34 { 35 int target_bits = 0; 36 37 if (host_bits & float_flag_invalid) 38 target_bits |= 1; 39 if (host_bits & float_flag_divbyzero) 40 target_bits |= 2; 41 if (host_bits & float_flag_overflow) 42 target_bits |= 4; 43 if (host_bits & (float_flag_underflow | float_flag_output_denormal)) 44 target_bits |= 8; 45 if (host_bits & float_flag_inexact) 46 target_bits |= 0x10; 47 if (host_bits & float_flag_input_denormal) 48 target_bits |= 0x80; 49 return target_bits; 50 } 51 52 uint32_t HELPER(vfp_get_fpscr)(CPUARMState *env) 53 { 54 uint32_t i, fpscr; 55 56 fpscr = env->vfp.xregs[ARM_VFP_FPSCR] 57 | (env->vfp.vec_len << 16) 58 | (env->vfp.vec_stride << 20); 59 60 i = get_float_exception_flags(&env->vfp.fp_status); 61 i |= get_float_exception_flags(&env->vfp.standard_fp_status); 62 /* FZ16 does not generate an input denormal exception. */ 63 i |= (get_float_exception_flags(&env->vfp.fp_status_f16) 64 & ~float_flag_input_denormal); 65 fpscr |= vfp_exceptbits_from_host(i); 66 67 i = env->vfp.qc[0] | env->vfp.qc[1] | env->vfp.qc[2] | env->vfp.qc[3]; 68 fpscr |= i ? FPCR_QC : 0; 69 70 return fpscr; 71 } 72 73 uint32_t vfp_get_fpscr(CPUARMState *env) 74 { 75 return HELPER(vfp_get_fpscr)(env); 76 } 77 78 /* Convert vfp exception flags to target form. */ 79 static inline int vfp_exceptbits_to_host(int target_bits) 80 { 81 int host_bits = 0; 82 83 if (target_bits & 1) 84 host_bits |= float_flag_invalid; 85 if (target_bits & 2) 86 host_bits |= float_flag_divbyzero; 87 if (target_bits & 4) 88 host_bits |= float_flag_overflow; 89 if (target_bits & 8) 90 host_bits |= float_flag_underflow; 91 if (target_bits & 0x10) 92 host_bits |= float_flag_inexact; 93 if (target_bits & 0x80) 94 host_bits |= float_flag_input_denormal; 95 return host_bits; 96 } 97 98 void HELPER(vfp_set_fpscr)(CPUARMState *env, uint32_t val) 99 { 100 int i; 101 uint32_t changed = env->vfp.xregs[ARM_VFP_FPSCR]; 102 103 /* When ARMv8.2-FP16 is not supported, FZ16 is RES0. */ 104 if (!cpu_isar_feature(aa64_fp16, arm_env_get_cpu(env))) { 105 val &= ~FPCR_FZ16; 106 } 107 108 /* 109 * We don't implement trapped exception handling, so the 110 * trap enable bits, IDE|IXE|UFE|OFE|DZE|IOE are all RAZ/WI (not RES0!) 111 * 112 * If we exclude the exception flags, IOC|DZC|OFC|UFC|IXC|IDC 113 * (which are stored in fp_status), and the other RES0 bits 114 * in between, then we clear all of the low 16 bits. 115 */ 116 env->vfp.xregs[ARM_VFP_FPSCR] = val & 0xf7c80000; 117 env->vfp.vec_len = (val >> 16) & 7; 118 env->vfp.vec_stride = (val >> 20) & 3; 119 120 /* 121 * The bit we set within fpscr_q is arbitrary; the register as a 122 * whole being zero/non-zero is what counts. 123 */ 124 env->vfp.qc[0] = val & FPCR_QC; 125 env->vfp.qc[1] = 0; 126 env->vfp.qc[2] = 0; 127 env->vfp.qc[3] = 0; 128 129 changed ^= val; 130 if (changed & (3 << 22)) { 131 i = (val >> 22) & 3; 132 switch (i) { 133 case FPROUNDING_TIEEVEN: 134 i = float_round_nearest_even; 135 break; 136 case FPROUNDING_POSINF: 137 i = float_round_up; 138 break; 139 case FPROUNDING_NEGINF: 140 i = float_round_down; 141 break; 142 case FPROUNDING_ZERO: 143 i = float_round_to_zero; 144 break; 145 } 146 set_float_rounding_mode(i, &env->vfp.fp_status); 147 set_float_rounding_mode(i, &env->vfp.fp_status_f16); 148 } 149 if (changed & FPCR_FZ16) { 150 bool ftz_enabled = val & FPCR_FZ16; 151 set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16); 152 set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16); 153 } 154 if (changed & FPCR_FZ) { 155 bool ftz_enabled = val & FPCR_FZ; 156 set_flush_to_zero(ftz_enabled, &env->vfp.fp_status); 157 set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status); 158 } 159 if (changed & FPCR_DN) { 160 bool dnan_enabled = val & FPCR_DN; 161 set_default_nan_mode(dnan_enabled, &env->vfp.fp_status); 162 set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16); 163 } 164 165 /* The exception flags are ORed together when we read fpscr so we 166 * only need to preserve the current state in one of our 167 * float_status values. 168 */ 169 i = vfp_exceptbits_to_host(val); 170 set_float_exception_flags(i, &env->vfp.fp_status); 171 set_float_exception_flags(0, &env->vfp.fp_status_f16); 172 set_float_exception_flags(0, &env->vfp.standard_fp_status); 173 } 174 175 void vfp_set_fpscr(CPUARMState *env, uint32_t val) 176 { 177 HELPER(vfp_set_fpscr)(env, val); 178 } 179 180 #define VFP_HELPER(name, p) HELPER(glue(glue(vfp_,name),p)) 181 182 #define VFP_BINOP(name) \ 183 float32 VFP_HELPER(name, s)(float32 a, float32 b, void *fpstp) \ 184 { \ 185 float_status *fpst = fpstp; \ 186 return float32_ ## name(a, b, fpst); \ 187 } \ 188 float64 VFP_HELPER(name, d)(float64 a, float64 b, void *fpstp) \ 189 { \ 190 float_status *fpst = fpstp; \ 191 return float64_ ## name(a, b, fpst); \ 192 } 193 VFP_BINOP(add) 194 VFP_BINOP(sub) 195 VFP_BINOP(mul) 196 VFP_BINOP(div) 197 VFP_BINOP(min) 198 VFP_BINOP(max) 199 VFP_BINOP(minnum) 200 VFP_BINOP(maxnum) 201 #undef VFP_BINOP 202 203 float32 VFP_HELPER(neg, s)(float32 a) 204 { 205 return float32_chs(a); 206 } 207 208 float64 VFP_HELPER(neg, d)(float64 a) 209 { 210 return float64_chs(a); 211 } 212 213 float32 VFP_HELPER(abs, s)(float32 a) 214 { 215 return float32_abs(a); 216 } 217 218 float64 VFP_HELPER(abs, d)(float64 a) 219 { 220 return float64_abs(a); 221 } 222 223 float32 VFP_HELPER(sqrt, s)(float32 a, CPUARMState *env) 224 { 225 return float32_sqrt(a, &env->vfp.fp_status); 226 } 227 228 float64 VFP_HELPER(sqrt, d)(float64 a, CPUARMState *env) 229 { 230 return float64_sqrt(a, &env->vfp.fp_status); 231 } 232 233 static void softfloat_to_vfp_compare(CPUARMState *env, int cmp) 234 { 235 uint32_t flags; 236 switch (cmp) { 237 case float_relation_equal: 238 flags = 0x6; 239 break; 240 case float_relation_less: 241 flags = 0x8; 242 break; 243 case float_relation_greater: 244 flags = 0x2; 245 break; 246 case float_relation_unordered: 247 flags = 0x3; 248 break; 249 default: 250 g_assert_not_reached(); 251 } 252 env->vfp.xregs[ARM_VFP_FPSCR] = 253 deposit32(env->vfp.xregs[ARM_VFP_FPSCR], 28, 4, flags); 254 } 255 256 /* XXX: check quiet/signaling case */ 257 #define DO_VFP_cmp(p, type) \ 258 void VFP_HELPER(cmp, p)(type a, type b, CPUARMState *env) \ 259 { \ 260 softfloat_to_vfp_compare(env, \ 261 type ## _compare_quiet(a, b, &env->vfp.fp_status)); \ 262 } \ 263 void VFP_HELPER(cmpe, p)(type a, type b, CPUARMState *env) \ 264 { \ 265 softfloat_to_vfp_compare(env, \ 266 type ## _compare(a, b, &env->vfp.fp_status)); \ 267 } 268 DO_VFP_cmp(s, float32) 269 DO_VFP_cmp(d, float64) 270 #undef DO_VFP_cmp 271 272 /* Integer to float and float to integer conversions */ 273 274 #define CONV_ITOF(name, ftype, fsz, sign) \ 275 ftype HELPER(name)(uint32_t x, void *fpstp) \ 276 { \ 277 float_status *fpst = fpstp; \ 278 return sign##int32_to_##float##fsz((sign##int32_t)x, fpst); \ 279 } 280 281 #define CONV_FTOI(name, ftype, fsz, sign, round) \ 282 sign##int32_t HELPER(name)(ftype x, void *fpstp) \ 283 { \ 284 float_status *fpst = fpstp; \ 285 if (float##fsz##_is_any_nan(x)) { \ 286 float_raise(float_flag_invalid, fpst); \ 287 return 0; \ 288 } \ 289 return float##fsz##_to_##sign##int32##round(x, fpst); \ 290 } 291 292 #define FLOAT_CONVS(name, p, ftype, fsz, sign) \ 293 CONV_ITOF(vfp_##name##to##p, ftype, fsz, sign) \ 294 CONV_FTOI(vfp_to##name##p, ftype, fsz, sign, ) \ 295 CONV_FTOI(vfp_to##name##z##p, ftype, fsz, sign, _round_to_zero) 296 297 FLOAT_CONVS(si, h, uint32_t, 16, ) 298 FLOAT_CONVS(si, s, float32, 32, ) 299 FLOAT_CONVS(si, d, float64, 64, ) 300 FLOAT_CONVS(ui, h, uint32_t, 16, u) 301 FLOAT_CONVS(ui, s, float32, 32, u) 302 FLOAT_CONVS(ui, d, float64, 64, u) 303 304 #undef CONV_ITOF 305 #undef CONV_FTOI 306 #undef FLOAT_CONVS 307 308 /* floating point conversion */ 309 float64 VFP_HELPER(fcvtd, s)(float32 x, CPUARMState *env) 310 { 311 return float32_to_float64(x, &env->vfp.fp_status); 312 } 313 314 float32 VFP_HELPER(fcvts, d)(float64 x, CPUARMState *env) 315 { 316 return float64_to_float32(x, &env->vfp.fp_status); 317 } 318 319 /* VFP3 fixed point conversion. */ 320 #define VFP_CONV_FIX_FLOAT(name, p, fsz, isz, itype) \ 321 float##fsz HELPER(vfp_##name##to##p)(uint##isz##_t x, uint32_t shift, \ 322 void *fpstp) \ 323 { return itype##_to_##float##fsz##_scalbn(x, -shift, fpstp); } 324 325 #define VFP_CONV_FLOAT_FIX_ROUND(name, p, fsz, isz, itype, ROUND, suff) \ 326 uint##isz##_t HELPER(vfp_to##name##p##suff)(float##fsz x, uint32_t shift, \ 327 void *fpst) \ 328 { \ 329 if (unlikely(float##fsz##_is_any_nan(x))) { \ 330 float_raise(float_flag_invalid, fpst); \ 331 return 0; \ 332 } \ 333 return float##fsz##_to_##itype##_scalbn(x, ROUND, shift, fpst); \ 334 } 335 336 #define VFP_CONV_FIX(name, p, fsz, isz, itype) \ 337 VFP_CONV_FIX_FLOAT(name, p, fsz, isz, itype) \ 338 VFP_CONV_FLOAT_FIX_ROUND(name, p, fsz, isz, itype, \ 339 float_round_to_zero, _round_to_zero) \ 340 VFP_CONV_FLOAT_FIX_ROUND(name, p, fsz, isz, itype, \ 341 get_float_rounding_mode(fpst), ) 342 343 #define VFP_CONV_FIX_A64(name, p, fsz, isz, itype) \ 344 VFP_CONV_FIX_FLOAT(name, p, fsz, isz, itype) \ 345 VFP_CONV_FLOAT_FIX_ROUND(name, p, fsz, isz, itype, \ 346 get_float_rounding_mode(fpst), ) 347 348 VFP_CONV_FIX(sh, d, 64, 64, int16) 349 VFP_CONV_FIX(sl, d, 64, 64, int32) 350 VFP_CONV_FIX_A64(sq, d, 64, 64, int64) 351 VFP_CONV_FIX(uh, d, 64, 64, uint16) 352 VFP_CONV_FIX(ul, d, 64, 64, uint32) 353 VFP_CONV_FIX_A64(uq, d, 64, 64, uint64) 354 VFP_CONV_FIX(sh, s, 32, 32, int16) 355 VFP_CONV_FIX(sl, s, 32, 32, int32) 356 VFP_CONV_FIX_A64(sq, s, 32, 64, int64) 357 VFP_CONV_FIX(uh, s, 32, 32, uint16) 358 VFP_CONV_FIX(ul, s, 32, 32, uint32) 359 VFP_CONV_FIX_A64(uq, s, 32, 64, uint64) 360 361 #undef VFP_CONV_FIX 362 #undef VFP_CONV_FIX_FLOAT 363 #undef VFP_CONV_FLOAT_FIX_ROUND 364 #undef VFP_CONV_FIX_A64 365 366 uint32_t HELPER(vfp_sltoh)(uint32_t x, uint32_t shift, void *fpst) 367 { 368 return int32_to_float16_scalbn(x, -shift, fpst); 369 } 370 371 uint32_t HELPER(vfp_ultoh)(uint32_t x, uint32_t shift, void *fpst) 372 { 373 return uint32_to_float16_scalbn(x, -shift, fpst); 374 } 375 376 uint32_t HELPER(vfp_sqtoh)(uint64_t x, uint32_t shift, void *fpst) 377 { 378 return int64_to_float16_scalbn(x, -shift, fpst); 379 } 380 381 uint32_t HELPER(vfp_uqtoh)(uint64_t x, uint32_t shift, void *fpst) 382 { 383 return uint64_to_float16_scalbn(x, -shift, fpst); 384 } 385 386 uint32_t HELPER(vfp_toshh)(uint32_t x, uint32_t shift, void *fpst) 387 { 388 if (unlikely(float16_is_any_nan(x))) { 389 float_raise(float_flag_invalid, fpst); 390 return 0; 391 } 392 return float16_to_int16_scalbn(x, get_float_rounding_mode(fpst), 393 shift, fpst); 394 } 395 396 uint32_t HELPER(vfp_touhh)(uint32_t x, uint32_t shift, void *fpst) 397 { 398 if (unlikely(float16_is_any_nan(x))) { 399 float_raise(float_flag_invalid, fpst); 400 return 0; 401 } 402 return float16_to_uint16_scalbn(x, get_float_rounding_mode(fpst), 403 shift, fpst); 404 } 405 406 uint32_t HELPER(vfp_toslh)(uint32_t x, uint32_t shift, void *fpst) 407 { 408 if (unlikely(float16_is_any_nan(x))) { 409 float_raise(float_flag_invalid, fpst); 410 return 0; 411 } 412 return float16_to_int32_scalbn(x, get_float_rounding_mode(fpst), 413 shift, fpst); 414 } 415 416 uint32_t HELPER(vfp_toulh)(uint32_t x, uint32_t shift, void *fpst) 417 { 418 if (unlikely(float16_is_any_nan(x))) { 419 float_raise(float_flag_invalid, fpst); 420 return 0; 421 } 422 return float16_to_uint32_scalbn(x, get_float_rounding_mode(fpst), 423 shift, fpst); 424 } 425 426 uint64_t HELPER(vfp_tosqh)(uint32_t x, uint32_t shift, void *fpst) 427 { 428 if (unlikely(float16_is_any_nan(x))) { 429 float_raise(float_flag_invalid, fpst); 430 return 0; 431 } 432 return float16_to_int64_scalbn(x, get_float_rounding_mode(fpst), 433 shift, fpst); 434 } 435 436 uint64_t HELPER(vfp_touqh)(uint32_t x, uint32_t shift, void *fpst) 437 { 438 if (unlikely(float16_is_any_nan(x))) { 439 float_raise(float_flag_invalid, fpst); 440 return 0; 441 } 442 return float16_to_uint64_scalbn(x, get_float_rounding_mode(fpst), 443 shift, fpst); 444 } 445 446 /* Set the current fp rounding mode and return the old one. 447 * The argument is a softfloat float_round_ value. 448 */ 449 uint32_t HELPER(set_rmode)(uint32_t rmode, void *fpstp) 450 { 451 float_status *fp_status = fpstp; 452 453 uint32_t prev_rmode = get_float_rounding_mode(fp_status); 454 set_float_rounding_mode(rmode, fp_status); 455 456 return prev_rmode; 457 } 458 459 /* Set the current fp rounding mode in the standard fp status and return 460 * the old one. This is for NEON instructions that need to change the 461 * rounding mode but wish to use the standard FPSCR values for everything 462 * else. Always set the rounding mode back to the correct value after 463 * modifying it. 464 * The argument is a softfloat float_round_ value. 465 */ 466 uint32_t HELPER(set_neon_rmode)(uint32_t rmode, CPUARMState *env) 467 { 468 float_status *fp_status = &env->vfp.standard_fp_status; 469 470 uint32_t prev_rmode = get_float_rounding_mode(fp_status); 471 set_float_rounding_mode(rmode, fp_status); 472 473 return prev_rmode; 474 } 475 476 /* Half precision conversions. */ 477 float32 HELPER(vfp_fcvt_f16_to_f32)(uint32_t a, void *fpstp, uint32_t ahp_mode) 478 { 479 /* Squash FZ16 to 0 for the duration of conversion. In this case, 480 * it would affect flushing input denormals. 481 */ 482 float_status *fpst = fpstp; 483 flag save = get_flush_inputs_to_zero(fpst); 484 set_flush_inputs_to_zero(false, fpst); 485 float32 r = float16_to_float32(a, !ahp_mode, fpst); 486 set_flush_inputs_to_zero(save, fpst); 487 return r; 488 } 489 490 uint32_t HELPER(vfp_fcvt_f32_to_f16)(float32 a, void *fpstp, uint32_t ahp_mode) 491 { 492 /* Squash FZ16 to 0 for the duration of conversion. In this case, 493 * it would affect flushing output denormals. 494 */ 495 float_status *fpst = fpstp; 496 flag save = get_flush_to_zero(fpst); 497 set_flush_to_zero(false, fpst); 498 float16 r = float32_to_float16(a, !ahp_mode, fpst); 499 set_flush_to_zero(save, fpst); 500 return r; 501 } 502 503 float64 HELPER(vfp_fcvt_f16_to_f64)(uint32_t a, void *fpstp, uint32_t ahp_mode) 504 { 505 /* Squash FZ16 to 0 for the duration of conversion. In this case, 506 * it would affect flushing input denormals. 507 */ 508 float_status *fpst = fpstp; 509 flag save = get_flush_inputs_to_zero(fpst); 510 set_flush_inputs_to_zero(false, fpst); 511 float64 r = float16_to_float64(a, !ahp_mode, fpst); 512 set_flush_inputs_to_zero(save, fpst); 513 return r; 514 } 515 516 uint32_t HELPER(vfp_fcvt_f64_to_f16)(float64 a, void *fpstp, uint32_t ahp_mode) 517 { 518 /* Squash FZ16 to 0 for the duration of conversion. In this case, 519 * it would affect flushing output denormals. 520 */ 521 float_status *fpst = fpstp; 522 flag save = get_flush_to_zero(fpst); 523 set_flush_to_zero(false, fpst); 524 float16 r = float64_to_float16(a, !ahp_mode, fpst); 525 set_flush_to_zero(save, fpst); 526 return r; 527 } 528 529 #define float32_two make_float32(0x40000000) 530 #define float32_three make_float32(0x40400000) 531 #define float32_one_point_five make_float32(0x3fc00000) 532 533 float32 HELPER(recps_f32)(float32 a, float32 b, CPUARMState *env) 534 { 535 float_status *s = &env->vfp.standard_fp_status; 536 if ((float32_is_infinity(a) && float32_is_zero_or_denormal(b)) || 537 (float32_is_infinity(b) && float32_is_zero_or_denormal(a))) { 538 if (!(float32_is_zero(a) || float32_is_zero(b))) { 539 float_raise(float_flag_input_denormal, s); 540 } 541 return float32_two; 542 } 543 return float32_sub(float32_two, float32_mul(a, b, s), s); 544 } 545 546 float32 HELPER(rsqrts_f32)(float32 a, float32 b, CPUARMState *env) 547 { 548 float_status *s = &env->vfp.standard_fp_status; 549 float32 product; 550 if ((float32_is_infinity(a) && float32_is_zero_or_denormal(b)) || 551 (float32_is_infinity(b) && float32_is_zero_or_denormal(a))) { 552 if (!(float32_is_zero(a) || float32_is_zero(b))) { 553 float_raise(float_flag_input_denormal, s); 554 } 555 return float32_one_point_five; 556 } 557 product = float32_mul(a, b, s); 558 return float32_div(float32_sub(float32_three, product, s), float32_two, s); 559 } 560 561 /* NEON helpers. */ 562 563 /* Constants 256 and 512 are used in some helpers; we avoid relying on 564 * int->float conversions at run-time. */ 565 #define float64_256 make_float64(0x4070000000000000LL) 566 #define float64_512 make_float64(0x4080000000000000LL) 567 #define float16_maxnorm make_float16(0x7bff) 568 #define float32_maxnorm make_float32(0x7f7fffff) 569 #define float64_maxnorm make_float64(0x7fefffffffffffffLL) 570 571 /* Reciprocal functions 572 * 573 * The algorithm that must be used to calculate the estimate 574 * is specified by the ARM ARM, see FPRecipEstimate()/RecipEstimate 575 */ 576 577 /* See RecipEstimate() 578 * 579 * input is a 9 bit fixed point number 580 * input range 256 .. 511 for a number from 0.5 <= x < 1.0. 581 * result range 256 .. 511 for a number from 1.0 to 511/256. 582 */ 583 584 static int recip_estimate(int input) 585 { 586 int a, b, r; 587 assert(256 <= input && input < 512); 588 a = (input * 2) + 1; 589 b = (1 << 19) / a; 590 r = (b + 1) >> 1; 591 assert(256 <= r && r < 512); 592 return r; 593 } 594 595 /* 596 * Common wrapper to call recip_estimate 597 * 598 * The parameters are exponent and 64 bit fraction (without implicit 599 * bit) where the binary point is nominally at bit 52. Returns a 600 * float64 which can then be rounded to the appropriate size by the 601 * callee. 602 */ 603 604 static uint64_t call_recip_estimate(int *exp, int exp_off, uint64_t frac) 605 { 606 uint32_t scaled, estimate; 607 uint64_t result_frac; 608 int result_exp; 609 610 /* Handle sub-normals */ 611 if (*exp == 0) { 612 if (extract64(frac, 51, 1) == 0) { 613 *exp = -1; 614 frac <<= 2; 615 } else { 616 frac <<= 1; 617 } 618 } 619 620 /* scaled = UInt('1':fraction<51:44>) */ 621 scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8)); 622 estimate = recip_estimate(scaled); 623 624 result_exp = exp_off - *exp; 625 result_frac = deposit64(0, 44, 8, estimate); 626 if (result_exp == 0) { 627 result_frac = deposit64(result_frac >> 1, 51, 1, 1); 628 } else if (result_exp == -1) { 629 result_frac = deposit64(result_frac >> 2, 50, 2, 1); 630 result_exp = 0; 631 } 632 633 *exp = result_exp; 634 635 return result_frac; 636 } 637 638 static bool round_to_inf(float_status *fpst, bool sign_bit) 639 { 640 switch (fpst->float_rounding_mode) { 641 case float_round_nearest_even: /* Round to Nearest */ 642 return true; 643 case float_round_up: /* Round to +Inf */ 644 return !sign_bit; 645 case float_round_down: /* Round to -Inf */ 646 return sign_bit; 647 case float_round_to_zero: /* Round to Zero */ 648 return false; 649 } 650 651 g_assert_not_reached(); 652 } 653 654 uint32_t HELPER(recpe_f16)(uint32_t input, void *fpstp) 655 { 656 float_status *fpst = fpstp; 657 float16 f16 = float16_squash_input_denormal(input, fpst); 658 uint32_t f16_val = float16_val(f16); 659 uint32_t f16_sign = float16_is_neg(f16); 660 int f16_exp = extract32(f16_val, 10, 5); 661 uint32_t f16_frac = extract32(f16_val, 0, 10); 662 uint64_t f64_frac; 663 664 if (float16_is_any_nan(f16)) { 665 float16 nan = f16; 666 if (float16_is_signaling_nan(f16, fpst)) { 667 float_raise(float_flag_invalid, fpst); 668 nan = float16_silence_nan(f16, fpst); 669 } 670 if (fpst->default_nan_mode) { 671 nan = float16_default_nan(fpst); 672 } 673 return nan; 674 } else if (float16_is_infinity(f16)) { 675 return float16_set_sign(float16_zero, float16_is_neg(f16)); 676 } else if (float16_is_zero(f16)) { 677 float_raise(float_flag_divbyzero, fpst); 678 return float16_set_sign(float16_infinity, float16_is_neg(f16)); 679 } else if (float16_abs(f16) < (1 << 8)) { 680 /* Abs(value) < 2.0^-16 */ 681 float_raise(float_flag_overflow | float_flag_inexact, fpst); 682 if (round_to_inf(fpst, f16_sign)) { 683 return float16_set_sign(float16_infinity, f16_sign); 684 } else { 685 return float16_set_sign(float16_maxnorm, f16_sign); 686 } 687 } else if (f16_exp >= 29 && fpst->flush_to_zero) { 688 float_raise(float_flag_underflow, fpst); 689 return float16_set_sign(float16_zero, float16_is_neg(f16)); 690 } 691 692 f64_frac = call_recip_estimate(&f16_exp, 29, 693 ((uint64_t) f16_frac) << (52 - 10)); 694 695 /* result = sign : result_exp<4:0> : fraction<51:42> */ 696 f16_val = deposit32(0, 15, 1, f16_sign); 697 f16_val = deposit32(f16_val, 10, 5, f16_exp); 698 f16_val = deposit32(f16_val, 0, 10, extract64(f64_frac, 52 - 10, 10)); 699 return make_float16(f16_val); 700 } 701 702 float32 HELPER(recpe_f32)(float32 input, void *fpstp) 703 { 704 float_status *fpst = fpstp; 705 float32 f32 = float32_squash_input_denormal(input, fpst); 706 uint32_t f32_val = float32_val(f32); 707 bool f32_sign = float32_is_neg(f32); 708 int f32_exp = extract32(f32_val, 23, 8); 709 uint32_t f32_frac = extract32(f32_val, 0, 23); 710 uint64_t f64_frac; 711 712 if (float32_is_any_nan(f32)) { 713 float32 nan = f32; 714 if (float32_is_signaling_nan(f32, fpst)) { 715 float_raise(float_flag_invalid, fpst); 716 nan = float32_silence_nan(f32, fpst); 717 } 718 if (fpst->default_nan_mode) { 719 nan = float32_default_nan(fpst); 720 } 721 return nan; 722 } else if (float32_is_infinity(f32)) { 723 return float32_set_sign(float32_zero, float32_is_neg(f32)); 724 } else if (float32_is_zero(f32)) { 725 float_raise(float_flag_divbyzero, fpst); 726 return float32_set_sign(float32_infinity, float32_is_neg(f32)); 727 } else if (float32_abs(f32) < (1ULL << 21)) { 728 /* Abs(value) < 2.0^-128 */ 729 float_raise(float_flag_overflow | float_flag_inexact, fpst); 730 if (round_to_inf(fpst, f32_sign)) { 731 return float32_set_sign(float32_infinity, f32_sign); 732 } else { 733 return float32_set_sign(float32_maxnorm, f32_sign); 734 } 735 } else if (f32_exp >= 253 && fpst->flush_to_zero) { 736 float_raise(float_flag_underflow, fpst); 737 return float32_set_sign(float32_zero, float32_is_neg(f32)); 738 } 739 740 f64_frac = call_recip_estimate(&f32_exp, 253, 741 ((uint64_t) f32_frac) << (52 - 23)); 742 743 /* result = sign : result_exp<7:0> : fraction<51:29> */ 744 f32_val = deposit32(0, 31, 1, f32_sign); 745 f32_val = deposit32(f32_val, 23, 8, f32_exp); 746 f32_val = deposit32(f32_val, 0, 23, extract64(f64_frac, 52 - 23, 23)); 747 return make_float32(f32_val); 748 } 749 750 float64 HELPER(recpe_f64)(float64 input, void *fpstp) 751 { 752 float_status *fpst = fpstp; 753 float64 f64 = float64_squash_input_denormal(input, fpst); 754 uint64_t f64_val = float64_val(f64); 755 bool f64_sign = float64_is_neg(f64); 756 int f64_exp = extract64(f64_val, 52, 11); 757 uint64_t f64_frac = extract64(f64_val, 0, 52); 758 759 /* Deal with any special cases */ 760 if (float64_is_any_nan(f64)) { 761 float64 nan = f64; 762 if (float64_is_signaling_nan(f64, fpst)) { 763 float_raise(float_flag_invalid, fpst); 764 nan = float64_silence_nan(f64, fpst); 765 } 766 if (fpst->default_nan_mode) { 767 nan = float64_default_nan(fpst); 768 } 769 return nan; 770 } else if (float64_is_infinity(f64)) { 771 return float64_set_sign(float64_zero, float64_is_neg(f64)); 772 } else if (float64_is_zero(f64)) { 773 float_raise(float_flag_divbyzero, fpst); 774 return float64_set_sign(float64_infinity, float64_is_neg(f64)); 775 } else if ((f64_val & ~(1ULL << 63)) < (1ULL << 50)) { 776 /* Abs(value) < 2.0^-1024 */ 777 float_raise(float_flag_overflow | float_flag_inexact, fpst); 778 if (round_to_inf(fpst, f64_sign)) { 779 return float64_set_sign(float64_infinity, f64_sign); 780 } else { 781 return float64_set_sign(float64_maxnorm, f64_sign); 782 } 783 } else if (f64_exp >= 2045 && fpst->flush_to_zero) { 784 float_raise(float_flag_underflow, fpst); 785 return float64_set_sign(float64_zero, float64_is_neg(f64)); 786 } 787 788 f64_frac = call_recip_estimate(&f64_exp, 2045, f64_frac); 789 790 /* result = sign : result_exp<10:0> : fraction<51:0>; */ 791 f64_val = deposit64(0, 63, 1, f64_sign); 792 f64_val = deposit64(f64_val, 52, 11, f64_exp); 793 f64_val = deposit64(f64_val, 0, 52, f64_frac); 794 return make_float64(f64_val); 795 } 796 797 /* The algorithm that must be used to calculate the estimate 798 * is specified by the ARM ARM. 799 */ 800 801 static int do_recip_sqrt_estimate(int a) 802 { 803 int b, estimate; 804 805 assert(128 <= a && a < 512); 806 if (a < 256) { 807 a = a * 2 + 1; 808 } else { 809 a = (a >> 1) << 1; 810 a = (a + 1) * 2; 811 } 812 b = 512; 813 while (a * (b + 1) * (b + 1) < (1 << 28)) { 814 b += 1; 815 } 816 estimate = (b + 1) / 2; 817 assert(256 <= estimate && estimate < 512); 818 819 return estimate; 820 } 821 822 823 static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac) 824 { 825 int estimate; 826 uint32_t scaled; 827 828 if (*exp == 0) { 829 while (extract64(frac, 51, 1) == 0) { 830 frac = frac << 1; 831 *exp -= 1; 832 } 833 frac = extract64(frac, 0, 51) << 1; 834 } 835 836 if (*exp & 1) { 837 /* scaled = UInt('01':fraction<51:45>) */ 838 scaled = deposit32(1 << 7, 0, 7, extract64(frac, 45, 7)); 839 } else { 840 /* scaled = UInt('1':fraction<51:44>) */ 841 scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8)); 842 } 843 estimate = do_recip_sqrt_estimate(scaled); 844 845 *exp = (exp_off - *exp) / 2; 846 return extract64(estimate, 0, 8) << 44; 847 } 848 849 uint32_t HELPER(rsqrte_f16)(uint32_t input, void *fpstp) 850 { 851 float_status *s = fpstp; 852 float16 f16 = float16_squash_input_denormal(input, s); 853 uint16_t val = float16_val(f16); 854 bool f16_sign = float16_is_neg(f16); 855 int f16_exp = extract32(val, 10, 5); 856 uint16_t f16_frac = extract32(val, 0, 10); 857 uint64_t f64_frac; 858 859 if (float16_is_any_nan(f16)) { 860 float16 nan = f16; 861 if (float16_is_signaling_nan(f16, s)) { 862 float_raise(float_flag_invalid, s); 863 nan = float16_silence_nan(f16, s); 864 } 865 if (s->default_nan_mode) { 866 nan = float16_default_nan(s); 867 } 868 return nan; 869 } else if (float16_is_zero(f16)) { 870 float_raise(float_flag_divbyzero, s); 871 return float16_set_sign(float16_infinity, f16_sign); 872 } else if (f16_sign) { 873 float_raise(float_flag_invalid, s); 874 return float16_default_nan(s); 875 } else if (float16_is_infinity(f16)) { 876 return float16_zero; 877 } 878 879 /* Scale and normalize to a double-precision value between 0.25 and 1.0, 880 * preserving the parity of the exponent. */ 881 882 f64_frac = ((uint64_t) f16_frac) << (52 - 10); 883 884 f64_frac = recip_sqrt_estimate(&f16_exp, 44, f64_frac); 885 886 /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(2) */ 887 val = deposit32(0, 15, 1, f16_sign); 888 val = deposit32(val, 10, 5, f16_exp); 889 val = deposit32(val, 2, 8, extract64(f64_frac, 52 - 8, 8)); 890 return make_float16(val); 891 } 892 893 float32 HELPER(rsqrte_f32)(float32 input, void *fpstp) 894 { 895 float_status *s = fpstp; 896 float32 f32 = float32_squash_input_denormal(input, s); 897 uint32_t val = float32_val(f32); 898 uint32_t f32_sign = float32_is_neg(f32); 899 int f32_exp = extract32(val, 23, 8); 900 uint32_t f32_frac = extract32(val, 0, 23); 901 uint64_t f64_frac; 902 903 if (float32_is_any_nan(f32)) { 904 float32 nan = f32; 905 if (float32_is_signaling_nan(f32, s)) { 906 float_raise(float_flag_invalid, s); 907 nan = float32_silence_nan(f32, s); 908 } 909 if (s->default_nan_mode) { 910 nan = float32_default_nan(s); 911 } 912 return nan; 913 } else if (float32_is_zero(f32)) { 914 float_raise(float_flag_divbyzero, s); 915 return float32_set_sign(float32_infinity, float32_is_neg(f32)); 916 } else if (float32_is_neg(f32)) { 917 float_raise(float_flag_invalid, s); 918 return float32_default_nan(s); 919 } else if (float32_is_infinity(f32)) { 920 return float32_zero; 921 } 922 923 /* Scale and normalize to a double-precision value between 0.25 and 1.0, 924 * preserving the parity of the exponent. */ 925 926 f64_frac = ((uint64_t) f32_frac) << 29; 927 928 f64_frac = recip_sqrt_estimate(&f32_exp, 380, f64_frac); 929 930 /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(15) */ 931 val = deposit32(0, 31, 1, f32_sign); 932 val = deposit32(val, 23, 8, f32_exp); 933 val = deposit32(val, 15, 8, extract64(f64_frac, 52 - 8, 8)); 934 return make_float32(val); 935 } 936 937 float64 HELPER(rsqrte_f64)(float64 input, void *fpstp) 938 { 939 float_status *s = fpstp; 940 float64 f64 = float64_squash_input_denormal(input, s); 941 uint64_t val = float64_val(f64); 942 bool f64_sign = float64_is_neg(f64); 943 int f64_exp = extract64(val, 52, 11); 944 uint64_t f64_frac = extract64(val, 0, 52); 945 946 if (float64_is_any_nan(f64)) { 947 float64 nan = f64; 948 if (float64_is_signaling_nan(f64, s)) { 949 float_raise(float_flag_invalid, s); 950 nan = float64_silence_nan(f64, s); 951 } 952 if (s->default_nan_mode) { 953 nan = float64_default_nan(s); 954 } 955 return nan; 956 } else if (float64_is_zero(f64)) { 957 float_raise(float_flag_divbyzero, s); 958 return float64_set_sign(float64_infinity, float64_is_neg(f64)); 959 } else if (float64_is_neg(f64)) { 960 float_raise(float_flag_invalid, s); 961 return float64_default_nan(s); 962 } else if (float64_is_infinity(f64)) { 963 return float64_zero; 964 } 965 966 f64_frac = recip_sqrt_estimate(&f64_exp, 3068, f64_frac); 967 968 /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(44) */ 969 val = deposit64(0, 61, 1, f64_sign); 970 val = deposit64(val, 52, 11, f64_exp); 971 val = deposit64(val, 44, 8, extract64(f64_frac, 52 - 8, 8)); 972 return make_float64(val); 973 } 974 975 uint32_t HELPER(recpe_u32)(uint32_t a, void *fpstp) 976 { 977 /* float_status *s = fpstp; */ 978 int input, estimate; 979 980 if ((a & 0x80000000) == 0) { 981 return 0xffffffff; 982 } 983 984 input = extract32(a, 23, 9); 985 estimate = recip_estimate(input); 986 987 return deposit32(0, (32 - 9), 9, estimate); 988 } 989 990 uint32_t HELPER(rsqrte_u32)(uint32_t a, void *fpstp) 991 { 992 int estimate; 993 994 if ((a & 0xc0000000) == 0) { 995 return 0xffffffff; 996 } 997 998 estimate = do_recip_sqrt_estimate(extract32(a, 23, 9)); 999 1000 return deposit32(0, 23, 9, estimate); 1001 } 1002 1003 /* VFPv4 fused multiply-accumulate */ 1004 float32 VFP_HELPER(muladd, s)(float32 a, float32 b, float32 c, void *fpstp) 1005 { 1006 float_status *fpst = fpstp; 1007 return float32_muladd(a, b, c, 0, fpst); 1008 } 1009 1010 float64 VFP_HELPER(muladd, d)(float64 a, float64 b, float64 c, void *fpstp) 1011 { 1012 float_status *fpst = fpstp; 1013 return float64_muladd(a, b, c, 0, fpst); 1014 } 1015 1016 /* ARMv8 round to integral */ 1017 float32 HELPER(rints_exact)(float32 x, void *fp_status) 1018 { 1019 return float32_round_to_int(x, fp_status); 1020 } 1021 1022 float64 HELPER(rintd_exact)(float64 x, void *fp_status) 1023 { 1024 return float64_round_to_int(x, fp_status); 1025 } 1026 1027 float32 HELPER(rints)(float32 x, void *fp_status) 1028 { 1029 int old_flags = get_float_exception_flags(fp_status), new_flags; 1030 float32 ret; 1031 1032 ret = float32_round_to_int(x, fp_status); 1033 1034 /* Suppress any inexact exceptions the conversion produced */ 1035 if (!(old_flags & float_flag_inexact)) { 1036 new_flags = get_float_exception_flags(fp_status); 1037 set_float_exception_flags(new_flags & ~float_flag_inexact, fp_status); 1038 } 1039 1040 return ret; 1041 } 1042 1043 float64 HELPER(rintd)(float64 x, void *fp_status) 1044 { 1045 int old_flags = get_float_exception_flags(fp_status), new_flags; 1046 float64 ret; 1047 1048 ret = float64_round_to_int(x, fp_status); 1049 1050 new_flags = get_float_exception_flags(fp_status); 1051 1052 /* Suppress any inexact exceptions the conversion produced */ 1053 if (!(old_flags & float_flag_inexact)) { 1054 new_flags = get_float_exception_flags(fp_status); 1055 set_float_exception_flags(new_flags & ~float_flag_inexact, fp_status); 1056 } 1057 1058 return ret; 1059 } 1060 1061 /* Convert ARM rounding mode to softfloat */ 1062 int arm_rmode_to_sf(int rmode) 1063 { 1064 switch (rmode) { 1065 case FPROUNDING_TIEAWAY: 1066 rmode = float_round_ties_away; 1067 break; 1068 case FPROUNDING_ODD: 1069 /* FIXME: add support for TIEAWAY and ODD */ 1070 qemu_log_mask(LOG_UNIMP, "arm: unimplemented rounding mode: %d\n", 1071 rmode); 1072 /* fall through for now */ 1073 case FPROUNDING_TIEEVEN: 1074 default: 1075 rmode = float_round_nearest_even; 1076 break; 1077 case FPROUNDING_POSINF: 1078 rmode = float_round_up; 1079 break; 1080 case FPROUNDING_NEGINF: 1081 rmode = float_round_down; 1082 break; 1083 case FPROUNDING_ZERO: 1084 rmode = float_round_to_zero; 1085 break; 1086 } 1087 return rmode; 1088 } 1089 1090 /* 1091 * Implement float64 to int32_t conversion without saturation; 1092 * the result is supplied modulo 2^32. 1093 */ 1094 uint64_t HELPER(fjcvtzs)(float64 value, void *vstatus) 1095 { 1096 float_status *status = vstatus; 1097 uint32_t exp, sign; 1098 uint64_t frac; 1099 uint32_t inexact = 1; /* !Z */ 1100 1101 sign = extract64(value, 63, 1); 1102 exp = extract64(value, 52, 11); 1103 frac = extract64(value, 0, 52); 1104 1105 if (exp == 0) { 1106 /* While not inexact for IEEE FP, -0.0 is inexact for JavaScript. */ 1107 inexact = sign; 1108 if (frac != 0) { 1109 if (status->flush_inputs_to_zero) { 1110 float_raise(float_flag_input_denormal, status); 1111 } else { 1112 float_raise(float_flag_inexact, status); 1113 inexact = 1; 1114 } 1115 } 1116 frac = 0; 1117 } else if (exp == 0x7ff) { 1118 /* This operation raises Invalid for both NaN and overflow (Inf). */ 1119 float_raise(float_flag_invalid, status); 1120 frac = 0; 1121 } else { 1122 int true_exp = exp - 1023; 1123 int shift = true_exp - 52; 1124 1125 /* Restore implicit bit. */ 1126 frac |= 1ull << 52; 1127 1128 /* Shift the fraction into place. */ 1129 if (shift >= 0) { 1130 /* The number is so large we must shift the fraction left. */ 1131 if (shift >= 64) { 1132 /* The fraction is shifted out entirely. */ 1133 frac = 0; 1134 } else { 1135 frac <<= shift; 1136 } 1137 } else if (shift > -64) { 1138 /* Normal case -- shift right and notice if bits shift out. */ 1139 inexact = (frac << (64 + shift)) != 0; 1140 frac >>= -shift; 1141 } else { 1142 /* The fraction is shifted out entirely. */ 1143 frac = 0; 1144 } 1145 1146 /* Notice overflow or inexact exceptions. */ 1147 if (true_exp > 31 || frac > (sign ? 0x80000000ull : 0x7fffffff)) { 1148 /* Overflow, for which this operation raises invalid. */ 1149 float_raise(float_flag_invalid, status); 1150 inexact = 1; 1151 } else if (inexact) { 1152 float_raise(float_flag_inexact, status); 1153 } 1154 1155 /* Honor the sign. */ 1156 if (sign) { 1157 frac = -frac; 1158 } 1159 } 1160 1161 /* Pack the result and the env->ZF representation of Z together. */ 1162 return deposit64(frac, 32, 32, inexact); 1163 } 1164 1165 uint32_t HELPER(vjcvt)(float64 value, CPUARMState *env) 1166 { 1167 uint64_t pair = HELPER(fjcvtzs)(value, &env->vfp.fp_status); 1168 uint32_t result = pair; 1169 uint32_t z = (pair >> 32) == 0; 1170 1171 /* Store Z, clear NCV, in FPSCR.NZCV. */ 1172 env->vfp.xregs[ARM_VFP_FPSCR] 1173 = (env->vfp.xregs[ARM_VFP_FPSCR] & ~CPSR_NZCV) | (z * CPSR_Z); 1174 1175 return result; 1176 } 1177