include/qemu/host-utils.h

   1 /*
   2  * Utility compute operations used by translated code.
   3  *
   4  * Copyright (c) 2007 Thiemo Seufer
   5  * Copyright (c) 2007 Jocelyn Mayer
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25 #ifndef HOST_UTILS_H
  26 #define HOST_UTILS_H 1
  27
  28 #include "qemu/compiler.h"   /* QEMU_GNUC_PREREQ */
  29 #include <limits.h>
  30 #include <stdbool.h>
  31
  32 #ifdef CONFIG_INT128
  33 static inline void mulu64(uint64_t *plow, uint64_t *phigh,
  34                           uint64_t a, uint64_t b)
  35 {
  36     __uint128_t r = (__uint128_t)a * b;
  37     *plow = r;
  38     *phigh = r >> 64;
  39 }
  40
  41 static inline void muls64(uint64_t *plow, uint64_t *phigh,
  42                           int64_t a, int64_t b)
  43 {
  44     __int128_t r = (__int128_t)a * b;
  45     *plow = r;
  46     *phigh = r >> 64;
  47 }
  48
  49 /* compute with 96 bit intermediate result: (a*b)/c */
  50 static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
  51 {
  52     return (__int128_t)a * b / c;
  53 }
  54
  55 static inline int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor)
  56 {
  57     if (divisor == 0) {
  58         return 1;
  59     } else {
  60         __uint128_t dividend = ((__uint128_t)*phigh << 64) | *plow;
  61         __uint128_t result = dividend / divisor;
  62         *plow = result;
  63         *phigh = dividend % divisor;
  64         return result > UINT64_MAX;
  65     }
  66 }
  67
  68 static inline int divs128(int64_t *plow, int64_t *phigh, int64_t divisor)
  69 {
  70     if (divisor == 0) {
  71         return 1;
  72     } else {
  73         __int128_t dividend = ((__int128_t)*phigh << 64) | *plow;
  74         __int128_t result = dividend / divisor;
  75         *plow = result;
  76         *phigh = dividend % divisor;
  77         return result != *plow;
  78     }
  79 }
  80 #else
  81 void muls64(uint64_t *phigh, uint64_t *plow, int64_t a, int64_t b);
  82 void mulu64(uint64_t *phigh, uint64_t *plow, uint64_t a, uint64_t b);
  83 int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor);
  84 int divs128(int64_t *plow, int64_t *phigh, int64_t divisor);
  85
  86 static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
  87 {
  88     union {
  89         uint64_t ll;
  90         struct {
  91 #ifdef HOST_WORDS_BIGENDIAN
  92             uint32_t high, low;
  93 #else
  94             uint32_t low, high;
  95 #endif
  96         } l;
  97     } u, res;
  98     uint64_t rl, rh;
  99
 100     u.ll = a;
 101     rl = (uint64_t)u.l.low * (uint64_t)b;
 102     rh = (uint64_t)u.l.high * (uint64_t)b;
 103     rh += (rl >> 32);
 104     res.l.high = rh / c;
 105     res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
 106     return res.ll;
 107 }
 108 #endif
 109
 110 /**
 111  * clz32 - count leading zeros in a 32-bit value.
 112  * @val: The value to search
 113  *
 114  * Returns 32 if the value is zero.  Note that the GCC builtin is
 115  * undefined if the value is zero.
 116  */
 117 static inline int clz32(uint32_t val)
 118 {
 119 #if QEMU_GNUC_PREREQ(3, 4)
 120     return val ? __builtin_clz(val) : 32;
 121 #else
 122     /* Binary search for the leading one bit.  */
 123     int cnt = 0;
 124
 125     if (!(val & 0xFFFF0000U)) {
 126         cnt += 16;
 127         val <<= 16;
 128     }
 129     if (!(val & 0xFF000000U)) {
 130         cnt += 8;
 131         val <<= 8;
 132     }
 133     if (!(val & 0xF0000000U)) {
 134         cnt += 4;
 135         val <<= 4;
 136     }
 137     if (!(val & 0xC0000000U)) {
 138         cnt += 2;
 139         val <<= 2;
 140     }
 141     if (!(val & 0x80000000U)) {
 142         cnt++;
 143         val <<= 1;
 144     }
 145     if (!(val & 0x80000000U)) {
 146         cnt++;
 147     }
 148     return cnt;
 149 #endif
 150 }
 151
 152 /**
 153  * clo32 - count leading ones in a 32-bit value.
 154  * @val: The value to search
 155  *
 156  * Returns 32 if the value is -1.
 157  */
 158 static inline int clo32(uint32_t val)
 159 {
 160     return clz32(~val);
 161 }
 162
 163 /**
 164  * clz64 - count leading zeros in a 64-bit value.
 165  * @val: The value to search
 166  *
 167  * Returns 64 if the value is zero.  Note that the GCC builtin is
 168  * undefined if the value is zero.
 169  */
 170 static inline int clz64(uint64_t val)
 171 {
 172 #if QEMU_GNUC_PREREQ(3, 4)
 173     return val ? __builtin_clzll(val) : 64;
 174 #else
 175     int cnt = 0;
 176
 177     if (!(val >> 32)) {
 178         cnt += 32;
 179     } else {
 180         val >>= 32;
 181     }
 182
 183     return cnt + clz32(val);
 184 #endif
 185 }
 186
 187 /**
 188  * clo64 - count leading ones in a 64-bit value.
 189  * @val: The value to search
 190  *
 191  * Returns 64 if the value is -1.
 192  */
 193 static inline int clo64(uint64_t val)
 194 {
 195     return clz64(~val);
 196 }
 197
 198 /**
 199  * ctz32 - count trailing zeros in a 32-bit value.
 200  * @val: The value to search
 201  *
 202  * Returns 32 if the value is zero.  Note that the GCC builtin is
 203  * undefined if the value is zero.
 204  */
 205 static inline int ctz32(uint32_t val)
 206 {
 207 #if QEMU_GNUC_PREREQ(3, 4)
 208     return val ? __builtin_ctz(val) : 32;
 209 #else
 210     /* Binary search for the trailing one bit.  */
 211     int cnt;
 212
 213     cnt = 0;
 214     if (!(val & 0x0000FFFFUL)) {
 215         cnt += 16;
 216         val >>= 16;
 217     }
 218     if (!(val & 0x000000FFUL)) {
 219         cnt += 8;
 220         val >>= 8;
 221     }
 222     if (!(val & 0x0000000FUL)) {
 223         cnt += 4;
 224         val >>= 4;
 225     }
 226     if (!(val & 0x00000003UL)) {
 227         cnt += 2;
 228         val >>= 2;
 229     }
 230     if (!(val & 0x00000001UL)) {
 231         cnt++;
 232         val >>= 1;
 233     }
 234     if (!(val & 0x00000001UL)) {
 235         cnt++;
 236     }
 237
 238     return cnt;
 239 #endif
 240 }
 241
 242 /**
 243  * cto32 - count trailing ones in a 32-bit value.
 244  * @val: The value to search
 245  *
 246  * Returns 32 if the value is -1.
 247  */
 248 static inline int cto32(uint32_t val)
 249 {
 250     return ctz32(~val);
 251 }
 252
 253 /**
 254  * ctz64 - count trailing zeros in a 64-bit value.
 255  * @val: The value to search
 256  *
 257  * Returns 64 if the value is zero.  Note that the GCC builtin is
 258  * undefined if the value is zero.
 259  */
 260 static inline int ctz64(uint64_t val)
 261 {
 262 #if QEMU_GNUC_PREREQ(3, 4)
 263     return val ? __builtin_ctzll(val) : 64;
 264 #else
 265     int cnt;
 266
 267     cnt = 0;
 268     if (!((uint32_t)val)) {
 269         cnt += 32;
 270         val >>= 32;
 271     }
 272
 273     return cnt + ctz32(val);
 274 #endif
 275 }
 276
 277 /**
 278  * cto64 - count trailing ones in a 64-bit value.
 279  * @val: The value to search
 280  *
 281  * Returns 64 if the value is -1.
 282  */
 283 static inline int cto64(uint64_t val)
 284 {
 285     return ctz64(~val);
 286 }
 287
 288 /**
 289  * clrsb32 - count leading redundant sign bits in a 32-bit value.
 290  * @val: The value to search
 291  *
 292  * Returns the number of bits following the sign bit that are equal to it.
 293  * No special cases; output range is [0-31].
 294  */
 295 static inline int clrsb32(uint32_t val)
 296 {
 297 #if QEMU_GNUC_PREREQ(4, 7)
 298     return __builtin_clrsb(val);
 299 #else
 300     return clz32(val ^ ((int32_t)val >> 1)) - 1;
 301 #endif
 302 }
 303
 304 /**
 305  * clrsb64 - count leading redundant sign bits in a 64-bit value.
 306  * @val: The value to search
 307  *
 308  * Returns the number of bits following the sign bit that are equal to it.
 309  * No special cases; output range is [0-63].
 310  */
 311 static inline int clrsb64(uint64_t val)
 312 {
 313 #if QEMU_GNUC_PREREQ(4, 7)
 314     return __builtin_clrsbll(val);
 315 #else
 316     return clz64(val ^ ((int64_t)val >> 1)) - 1;
 317 #endif
 318 }
 319
 320 /**
 321  * ctpop8 - count the population of one bits in an 8-bit value.
 322  * @val: The value to search
 323  */
 324 static inline int ctpop8(uint8_t val)
 325 {
 326 #if QEMU_GNUC_PREREQ(3, 4)
 327     return __builtin_popcount(val);
 328 #else
 329     val = (val & 0x55) + ((val >> 1) & 0x55);
 330     val = (val & 0x33) + ((val >> 2) & 0x33);
 331     val = (val & 0x0f) + ((val >> 4) & 0x0f);
 332
 333     return val;
 334 #endif
 335 }
 336
 337 /**
 338  * ctpop16 - count the population of one bits in a 16-bit value.
 339  * @val: The value to search
 340  */
 341 static inline int ctpop16(uint16_t val)
 342 {
 343 #if QEMU_GNUC_PREREQ(3, 4)
 344     return __builtin_popcount(val);
 345 #else
 346     val = (val & 0x5555) + ((val >> 1) & 0x5555);
 347     val = (val & 0x3333) + ((val >> 2) & 0x3333);
 348     val = (val & 0x0f0f) + ((val >> 4) & 0x0f0f);
 349     val = (val & 0x00ff) + ((val >> 8) & 0x00ff);
 350
 351     return val;
 352 #endif
 353 }
 354
 355 /**
 356  * ctpop32 - count the population of one bits in a 32-bit value.
 357  * @val: The value to search
 358  */
 359 static inline int ctpop32(uint32_t val)
 360 {
 361 #if QEMU_GNUC_PREREQ(3, 4)
 362     return __builtin_popcount(val);
 363 #else
 364     val = (val & 0x55555555) + ((val >>  1) & 0x55555555);
 365     val = (val & 0x33333333) + ((val >>  2) & 0x33333333);
 366     val = (val & 0x0f0f0f0f) + ((val >>  4) & 0x0f0f0f0f);
 367     val = (val & 0x00ff00ff) + ((val >>  8) & 0x00ff00ff);
 368     val = (val & 0x0000ffff) + ((val >> 16) & 0x0000ffff);
 369
 370     return val;
 371 #endif
 372 }
 373
 374 /**
 375  * ctpop64 - count the population of one bits in a 64-bit value.
 376  * @val: The value to search
 377  */
 378 static inline int ctpop64(uint64_t val)
 379 {
 380 #if QEMU_GNUC_PREREQ(3, 4)
 381     return __builtin_popcountll(val);
 382 #else
 383     val = (val & 0x5555555555555555ULL) + ((val >>  1) & 0x5555555555555555ULL);
 384     val = (val & 0x3333333333333333ULL) + ((val >>  2) & 0x3333333333333333ULL);
 385     val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >>  4) & 0x0f0f0f0f0f0f0f0fULL);
 386     val = (val & 0x00ff00ff00ff00ffULL) + ((val >>  8) & 0x00ff00ff00ff00ffULL);
 387     val = (val & 0x0000ffff0000ffffULL) + ((val >> 16) & 0x0000ffff0000ffffULL);
 388     val = (val & 0x00000000ffffffffULL) + ((val >> 32) & 0x00000000ffffffffULL);
 389
 390     return val;
 391 #endif
 392 }
 393
 394 /* Host type specific sizes of these routines.  */
 395
 396 #if ULONG_MAX == UINT32_MAX
 397 # define clzl   clz32
 398 # define ctzl   ctz32
 399 # define clol   clo32
 400 # define ctol   cto32
 401 # define ctpopl ctpop32
 402 #elif ULONG_MAX == UINT64_MAX
 403 # define clzl   clz64
 404 # define ctzl   ctz64
 405 # define clol   clo64
 406 # define ctol   cto64
 407 # define ctpopl ctpop64
 408 #else
 409 # error Unknown sizeof long
 410 #endif
 411
 412 static inline bool is_power_of_2(uint64_t value)
 413 {
 414     if (!value) {
 415         return 0;
 416     }
 417
 418     return !(value & (value - 1));
 419 }
 420
 421 /* round down to the nearest power of 2*/
 422 static inline int64_t pow2floor(int64_t value)
 423 {
 424     if (!is_power_of_2(value)) {
 425         value = 0x8000000000000000ULL >> clz64(value);
 426     }
 427     return value;
 428 }
 429
 430 /* round up to the nearest power of 2 (0 if overflow) */
 431 static inline uint64_t pow2ceil(uint64_t value)
 432 {
 433     uint8_t nlz = clz64(value);
 434
 435     if (is_power_of_2(value)) {
 436         return value;
 437     }
 438     if (!nlz) {
 439         return 0;
 440     }
 441     return 1ULL << (64 - nlz);
 442 }
 443
 444 #endif