target/i386/int_helper.c

   1 /*
   2  *  x86 integer helpers
   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 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 "cpu.h"
  22 #include "exec/exec-all.h"
  23 #include "qemu/host-utils.h"
  24 #include "exec/helper-proto.h"
  25
  26 //#define DEBUG_MULDIV
  27
  28 /* modulo 9 table */
  29 static const uint8_t rclb_table[32] = {
  30     0, 1, 2, 3, 4, 5, 6, 7,
  31     8, 0, 1, 2, 3, 4, 5, 6,
  32     7, 8, 0, 1, 2, 3, 4, 5,
  33     6, 7, 8, 0, 1, 2, 3, 4,
  34 };
  35
  36 /* modulo 17 table */
  37 static const uint8_t rclw_table[32] = {
  38     0, 1, 2, 3, 4, 5, 6, 7,
  39     8, 9, 10, 11, 12, 13, 14, 15,
  40     16, 0, 1, 2, 3, 4, 5, 6,
  41     7, 8, 9, 10, 11, 12, 13, 14,
  42 };
  43
  44 /* division, flags are undefined */
  45
  46 void helper_divb_AL(CPUX86State *env, target_ulong t0)
  47 {
  48     unsigned int num, den, q, r;
  49
  50     num = (env->regs[R_EAX] & 0xffff);
  51     den = (t0 & 0xff);
  52     if (den == 0) {
  53         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
  54     }
  55     q = (num / den);
  56     if (q > 0xff) {
  57         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
  58     }
  59     q &= 0xff;
  60     r = (num % den) & 0xff;
  61     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | (r << 8) | q;
  62 }
  63
  64 void helper_idivb_AL(CPUX86State *env, target_ulong t0)
  65 {
  66     int num, den, q, r;
  67
  68     num = (int16_t)env->regs[R_EAX];
  69     den = (int8_t)t0;
  70     if (den == 0) {
  71         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
  72     }
  73     q = (num / den);
  74     if (q != (int8_t)q) {
  75         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
  76     }
  77     q &= 0xff;
  78     r = (num % den) & 0xff;
  79     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | (r << 8) | q;
  80 }
  81
  82 void helper_divw_AX(CPUX86State *env, target_ulong t0)
  83 {
  84     unsigned int num, den, q, r;
  85
  86     num = (env->regs[R_EAX] & 0xffff) | ((env->regs[R_EDX] & 0xffff) << 16);
  87     den = (t0 & 0xffff);
  88     if (den == 0) {
  89         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
  90     }
  91     q = (num / den);
  92     if (q > 0xffff) {
  93         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
  94     }
  95     q &= 0xffff;
  96     r = (num % den) & 0xffff;
  97     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | q;
  98     env->regs[R_EDX] = (env->regs[R_EDX] & ~0xffff) | r;
  99 }
 100
 101 void helper_idivw_AX(CPUX86State *env, target_ulong t0)
 102 {
 103     int num, den, q, r;
 104
 105     num = (env->regs[R_EAX] & 0xffff) | ((env->regs[R_EDX] & 0xffff) << 16);
 106     den = (int16_t)t0;
 107     if (den == 0) {
 108         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 109     }
 110     q = (num / den);
 111     if (q != (int16_t)q) {
 112         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 113     }
 114     q &= 0xffff;
 115     r = (num % den) & 0xffff;
 116     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | q;
 117     env->regs[R_EDX] = (env->regs[R_EDX] & ~0xffff) | r;
 118 }
 119
 120 void helper_divl_EAX(CPUX86State *env, target_ulong t0)
 121 {
 122     unsigned int den, r;
 123     uint64_t num, q;
 124
 125     num = ((uint32_t)env->regs[R_EAX]) | ((uint64_t)((uint32_t)env->regs[R_EDX]) << 32);
 126     den = t0;
 127     if (den == 0) {
 128         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 129     }
 130     q = (num / den);
 131     r = (num % den);
 132     if (q > 0xffffffff) {
 133         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 134     }
 135     env->regs[R_EAX] = (uint32_t)q;
 136     env->regs[R_EDX] = (uint32_t)r;
 137 }
 138
 139 void helper_idivl_EAX(CPUX86State *env, target_ulong t0)
 140 {
 141     int den, r;
 142     int64_t num, q;
 143
 144     num = ((uint32_t)env->regs[R_EAX]) | ((uint64_t)((uint32_t)env->regs[R_EDX]) << 32);
 145     den = t0;
 146     if (den == 0) {
 147         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 148     }
 149     q = (num / den);
 150     r = (num % den);
 151     if (q != (int32_t)q) {
 152         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 153     }
 154     env->regs[R_EAX] = (uint32_t)q;
 155     env->regs[R_EDX] = (uint32_t)r;
 156 }
 157
 158 /* bcd */
 159
 160 /* XXX: exception */
 161 void helper_aam(CPUX86State *env, int base)
 162 {
 163     int al, ah;
 164
 165     al = env->regs[R_EAX] & 0xff;
 166     ah = al / base;
 167     al = al % base;
 168     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al | (ah << 8);
 169     CC_DST = al;
 170 }
 171
 172 void helper_aad(CPUX86State *env, int base)
 173 {
 174     int al, ah;
 175
 176     al = env->regs[R_EAX] & 0xff;
 177     ah = (env->regs[R_EAX] >> 8) & 0xff;
 178     al = ((ah * base) + al) & 0xff;
 179     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al;
 180     CC_DST = al;
 181 }
 182
 183 void helper_aaa(CPUX86State *env)
 184 {
 185     int icarry;
 186     int al, ah, af;
 187     int eflags;
 188
 189     eflags = cpu_cc_compute_all(env, CC_OP);
 190     af = eflags & CC_A;
 191     al = env->regs[R_EAX] & 0xff;
 192     ah = (env->regs[R_EAX] >> 8) & 0xff;
 193
 194     icarry = (al > 0xf9);
 195     if (((al & 0x0f) > 9) || af) {
 196         al = (al + 6) & 0x0f;
 197         ah = (ah + 1 + icarry) & 0xff;
 198         eflags |= CC_C | CC_A;
 199     } else {
 200         eflags &= ~(CC_C | CC_A);
 201         al &= 0x0f;
 202     }
 203     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al | (ah << 8);
 204     CC_SRC = eflags;
 205 }
 206
 207 void helper_aas(CPUX86State *env)
 208 {
 209     int icarry;
 210     int al, ah, af;
 211     int eflags;
 212
 213     eflags = cpu_cc_compute_all(env, CC_OP);
 214     af = eflags & CC_A;
 215     al = env->regs[R_EAX] & 0xff;
 216     ah = (env->regs[R_EAX] >> 8) & 0xff;
 217
 218     icarry = (al < 6);
 219     if (((al & 0x0f) > 9) || af) {
 220         al = (al - 6) & 0x0f;
 221         ah = (ah - 1 - icarry) & 0xff;
 222         eflags |= CC_C | CC_A;
 223     } else {
 224         eflags &= ~(CC_C | CC_A);
 225         al &= 0x0f;
 226     }
 227     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al | (ah << 8);
 228     CC_SRC = eflags;
 229 }
 230
 231 void helper_daa(CPUX86State *env)
 232 {
 233     int old_al, al, af, cf;
 234     int eflags;
 235
 236     eflags = cpu_cc_compute_all(env, CC_OP);
 237     cf = eflags & CC_C;
 238     af = eflags & CC_A;
 239     old_al = al = env->regs[R_EAX] & 0xff;
 240
 241     eflags = 0;
 242     if (((al & 0x0f) > 9) || af) {
 243         al = (al + 6) & 0xff;
 244         eflags |= CC_A;
 245     }
 246     if ((old_al > 0x99) || cf) {
 247         al = (al + 0x60) & 0xff;
 248         eflags |= CC_C;
 249     }
 250     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | al;
 251     /* well, speed is not an issue here, so we compute the flags by hand */
 252     eflags |= (al == 0) << 6; /* zf */
 253     eflags |= parity_table[al]; /* pf */
 254     eflags |= (al & 0x80); /* sf */
 255     CC_SRC = eflags;
 256 }
 257
 258 void helper_das(CPUX86State *env)
 259 {
 260     int al, al1, af, cf;
 261     int eflags;
 262
 263     eflags = cpu_cc_compute_all(env, CC_OP);
 264     cf = eflags & CC_C;
 265     af = eflags & CC_A;
 266     al = env->regs[R_EAX] & 0xff;
 267
 268     eflags = 0;
 269     al1 = al;
 270     if (((al & 0x0f) > 9) || af) {
 271         eflags |= CC_A;
 272         if (al < 6 || cf) {
 273             eflags |= CC_C;
 274         }
 275         al = (al - 6) & 0xff;
 276     }
 277     if ((al1 > 0x99) || cf) {
 278         al = (al - 0x60) & 0xff;
 279         eflags |= CC_C;
 280     }
 281     env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | al;
 282     /* well, speed is not an issue here, so we compute the flags by hand */
 283     eflags |= (al == 0) << 6; /* zf */
 284     eflags |= parity_table[al]; /* pf */
 285     eflags |= (al & 0x80); /* sf */
 286     CC_SRC = eflags;
 287 }
 288
 289 #ifdef TARGET_X86_64
 290 static void add128(uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
 291 {
 292     *plow += a;
 293     /* carry test */
 294     if (*plow < a) {
 295         (*phigh)++;
 296     }
 297     *phigh += b;
 298 }
 299
 300 static void neg128(uint64_t *plow, uint64_t *phigh)
 301 {
 302     *plow = ~*plow;
 303     *phigh = ~*phigh;
 304     add128(plow, phigh, 1, 0);
 305 }
 306
 307 /* return TRUE if overflow */
 308 static int div64(uint64_t *plow, uint64_t *phigh, uint64_t b)
 309 {
 310     uint64_t q, r, a1, a0;
 311     int i, qb, ab;
 312
 313     a0 = *plow;
 314     a1 = *phigh;
 315     if (a1 == 0) {
 316         q = a0 / b;
 317         r = a0 % b;
 318         *plow = q;
 319         *phigh = r;
 320     } else {
 321         if (a1 >= b) {
 322             return 1;
 323         }
 324         /* XXX: use a better algorithm */
 325         for (i = 0; i < 64; i++) {
 326             ab = a1 >> 63;
 327             a1 = (a1 << 1) | (a0 >> 63);
 328             if (ab || a1 >= b) {
 329                 a1 -= b;
 330                 qb = 1;
 331             } else {
 332                 qb = 0;
 333             }
 334             a0 = (a0 << 1) | qb;
 335         }
 336 #if defined(DEBUG_MULDIV)
 337         printf("div: 0x%016" PRIx64 "%016" PRIx64 " / 0x%016" PRIx64
 338                ": q=0x%016" PRIx64 " r=0x%016" PRIx64 "\n",
 339                *phigh, *plow, b, a0, a1);
 340 #endif
 341         *plow = a0;
 342         *phigh = a1;
 343     }
 344     return 0;
 345 }
 346
 347 /* return TRUE if overflow */
 348 static int idiv64(uint64_t *plow, uint64_t *phigh, int64_t b)
 349 {
 350     int sa, sb;
 351
 352     sa = ((int64_t)*phigh < 0);
 353     if (sa) {
 354         neg128(plow, phigh);
 355     }
 356     sb = (b < 0);
 357     if (sb) {
 358         b = -b;
 359     }
 360     if (div64(plow, phigh, b) != 0) {
 361         return 1;
 362     }
 363     if (sa ^ sb) {
 364         if (*plow > (1ULL << 63)) {
 365             return 1;
 366         }
 367         *plow = -*plow;
 368     } else {
 369         if (*plow >= (1ULL << 63)) {
 370             return 1;
 371         }
 372     }
 373     if (sa) {
 374         *phigh = -*phigh;
 375     }
 376     return 0;
 377 }
 378
 379 void helper_divq_EAX(CPUX86State *env, target_ulong t0)
 380 {
 381     uint64_t r0, r1;
 382
 383     if (t0 == 0) {
 384         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 385     }
 386     r0 = env->regs[R_EAX];
 387     r1 = env->regs[R_EDX];
 388     if (div64(&r0, &r1, t0)) {
 389         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 390     }
 391     env->regs[R_EAX] = r0;
 392     env->regs[R_EDX] = r1;
 393 }
 394
 395 void helper_idivq_EAX(CPUX86State *env, target_ulong t0)
 396 {
 397     uint64_t r0, r1;
 398
 399     if (t0 == 0) {
 400         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 401     }
 402     r0 = env->regs[R_EAX];
 403     r1 = env->regs[R_EDX];
 404     if (idiv64(&r0, &r1, t0)) {
 405         raise_exception_ra(env, EXCP00_DIVZ, GETPC());
 406     }
 407     env->regs[R_EAX] = r0;
 408     env->regs[R_EDX] = r1;
 409 }
 410 #endif
 411
 412 #if TARGET_LONG_BITS == 32
 413 # define ctztl  ctz32
 414 # define clztl  clz32
 415 #else
 416 # define ctztl  ctz64
 417 # define clztl  clz64
 418 #endif
 419
 420 target_ulong helper_pdep(target_ulong src, target_ulong mask)
 421 {
 422     target_ulong dest = 0;
 423     int i, o;
 424
 425     for (i = 0; mask != 0; i++) {
 426         o = ctztl(mask);
 427         mask &= mask - 1;
 428         dest |= ((src >> i) & 1) << o;
 429     }
 430     return dest;
 431 }
 432
 433 target_ulong helper_pext(target_ulong src, target_ulong mask)
 434 {
 435     target_ulong dest = 0;
 436     int i, o;
 437
 438     for (o = 0; mask != 0; o++) {
 439         i = ctztl(mask);
 440         mask &= mask - 1;
 441         dest |= ((src >> i) & 1) << o;
 442     }
 443     return dest;
 444 }
 445
 446 #define SHIFT 0
 447 #include "shift_helper_template.h"
 448 #undef SHIFT
 449
 450 #define SHIFT 1
 451 #include "shift_helper_template.h"
 452 #undef SHIFT
 453
 454 #define SHIFT 2
 455 #include "shift_helper_template.h"
 456 #undef SHIFT
 457
 458 #ifdef TARGET_X86_64
 459 #define SHIFT 3
 460 #include "shift_helper_template.h"
 461 #undef SHIFT
 462 #endif
 463
 464 /* Test that BIT is enabled in CR4.  If not, raise an illegal opcode
 465    exception.  This reduces the requirements for rare CR4 bits being
 466    mapped into HFLAGS.  */
 467 void helper_cr4_testbit(CPUX86State *env, uint32_t bit)
 468 {
 469     if (unlikely((env->cr[4] & bit) == 0)) {
 470         raise_exception_ra(env, EXCP06_ILLOP, GETPC());
 471     }
 472 }