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
  26 #ifndef HOST_UTILS_H
  27 #define HOST_UTILS_H
  28
  29 #include "qemu/bswap.h"
  30
  31 #ifdef CONFIG_INT128
  32 static inline void mulu64(uint64_t *plow, uint64_t *phigh,
  33                           uint64_t a, uint64_t b)
  34 {
  35     __uint128_t r = (__uint128_t)a * b;
  36     *plow = r;
  37     *phigh = r >> 64;
  38 }
  39
  40 static inline void muls64(uint64_t *plow, uint64_t *phigh,
  41                           int64_t a, int64_t b)
  42 {
  43     __int128_t r = (__int128_t)a * b;
  44     *plow = r;
  45     *phigh = r >> 64;
  46 }
  47
  48 /* compute with 96 bit intermediate result: (a*b)/c */
  49 static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
  50 {
  51     return (__int128_t)a * b / c;
  52 }
  53
  54 static inline int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor)
  55 {
  56     if (divisor == 0) {
  57         return 1;
  58     } else {
  59         __uint128_t dividend = ((__uint128_t)*phigh << 64) | *plow;
  60         __uint128_t result = dividend / divisor;
  61         *plow = result;
  62         *phigh = dividend % divisor;
  63         return result > UINT64_MAX;
  64     }
  65 }
  66
  67 static inline int divs128(int64_t *plow, int64_t *phigh, int64_t divisor)
  68 {
  69     if (divisor == 0) {
  70         return 1;
  71     } else {
  72         __int128_t dividend = ((__int128_t)*phigh << 64) | *plow;
  73         __int128_t result = dividend / divisor;
  74         *plow = result;
  75         *phigh = dividend % divisor;
  76         return result != *plow;
  77     }
  78 }
  79 #else
  80 void muls64(uint64_t *phigh, uint64_t *plow, int64_t a, int64_t b);
  81 void mulu64(uint64_t *phigh, uint64_t *plow, uint64_t a, uint64_t b);
  82 int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor);
  83 int divs128(int64_t *plow, int64_t *phigh, int64_t divisor);
  84
  85 static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
  86 {
  87     union {
  88         uint64_t ll;
  89         struct {
  90 #ifdef HOST_WORDS_BIGENDIAN
  91             uint32_t high, low;
  92 #else
  93             uint32_t low, high;
  94 #endif
  95         } l;
  96     } u, res;
  97     uint64_t rl, rh;
  98
  99     u.ll = a;
 100     rl = (uint64_t)u.l.low * (uint64_t)b;
 101     rh = (uint64_t)u.l.high * (uint64_t)b;
 102     rh += (rl >> 32);
 103     res.l.high = rh / c;
 104     res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
 105     return res.ll;
 106 }
 107 #endif
 108
 109 /**
 110  * clz32 - count leading zeros in a 32-bit value.
 111  * @val: The value to search
 112  *
 113  * Returns 32 if the value is zero.  Note that the GCC builtin is
 114  * undefined if the value is zero.
 115  */
 116 static inline int clz32(uint32_t val)
 117 {
 118     return val ? __builtin_clz(val) : 32;
 119 }
 120
 121 /**
 122  * clo32 - count leading ones in a 32-bit value.
 123  * @val: The value to search
 124  *
 125  * Returns 32 if the value is -1.
 126  */
 127 static inline int clo32(uint32_t val)
 128 {
 129     return clz32(~val);
 130 }
 131
 132 /**
 133  * clz64 - count leading zeros in a 64-bit value.
 134  * @val: The value to search
 135  *
 136  * Returns 64 if the value is zero.  Note that the GCC builtin is
 137  * undefined if the value is zero.
 138  */
 139 static inline int clz64(uint64_t val)
 140 {
 141     return val ? __builtin_clzll(val) : 64;
 142 }
 143
 144 /**
 145  * clo64 - count leading ones in a 64-bit value.
 146  * @val: The value to search
 147  *
 148  * Returns 64 if the value is -1.
 149  */
 150 static inline int clo64(uint64_t val)
 151 {
 152     return clz64(~val);
 153 }
 154
 155 /**
 156  * ctz32 - count trailing zeros in a 32-bit value.
 157  * @val: The value to search
 158  *
 159  * Returns 32 if the value is zero.  Note that the GCC builtin is
 160  * undefined if the value is zero.
 161  */
 162 static inline int ctz32(uint32_t val)
 163 {
 164     return val ? __builtin_ctz(val) : 32;
 165 }
 166
 167 /**
 168  * cto32 - count trailing ones in a 32-bit value.
 169  * @val: The value to search
 170  *
 171  * Returns 32 if the value is -1.
 172  */
 173 static inline int cto32(uint32_t val)
 174 {
 175     return ctz32(~val);
 176 }
 177
 178 /**
 179  * ctz64 - count trailing zeros in a 64-bit value.
 180  * @val: The value to search
 181  *
 182  * Returns 64 if the value is zero.  Note that the GCC builtin is
 183  * undefined if the value is zero.
 184  */
 185 static inline int ctz64(uint64_t val)
 186 {
 187     return val ? __builtin_ctzll(val) : 64;
 188 }
 189
 190 /**
 191  * cto64 - count trailing ones in a 64-bit value.
 192  * @val: The value to search
 193  *
 194  * Returns 64 if the value is -1.
 195  */
 196 static inline int cto64(uint64_t val)
 197 {
 198     return ctz64(~val);
 199 }
 200
 201 /**
 202  * clrsb32 - count leading redundant sign bits in a 32-bit value.
 203  * @val: The value to search
 204  *
 205  * Returns the number of bits following the sign bit that are equal to it.
 206  * No special cases; output range is [0-31].
 207  */
 208 static inline int clrsb32(uint32_t val)
 209 {
 210 #if QEMU_GNUC_PREREQ(4, 7)
 211     return __builtin_clrsb(val);
 212 #else
 213     return clz32(val ^ ((int32_t)val >> 1)) - 1;
 214 #endif
 215 }
 216
 217 /**
 218  * clrsb64 - count leading redundant sign bits in a 64-bit value.
 219  * @val: The value to search
 220  *
 221  * Returns the number of bits following the sign bit that are equal to it.
 222  * No special cases; output range is [0-63].
 223  */
 224 static inline int clrsb64(uint64_t val)
 225 {
 226 #if QEMU_GNUC_PREREQ(4, 7)
 227     return __builtin_clrsbll(val);
 228 #else
 229     return clz64(val ^ ((int64_t)val >> 1)) - 1;
 230 #endif
 231 }
 232
 233 /**
 234  * ctpop8 - count the population of one bits in an 8-bit value.
 235  * @val: The value to search
 236  */
 237 static inline int ctpop8(uint8_t val)
 238 {
 239     return __builtin_popcount(val);
 240 }
 241
 242 /**
 243  * ctpop16 - count the population of one bits in a 16-bit value.
 244  * @val: The value to search
 245  */
 246 static inline int ctpop16(uint16_t val)
 247 {
 248     return __builtin_popcount(val);
 249 }
 250
 251 /**
 252  * ctpop32 - count the population of one bits in a 32-bit value.
 253  * @val: The value to search
 254  */
 255 static inline int ctpop32(uint32_t val)
 256 {
 257     return __builtin_popcount(val);
 258 }
 259
 260 /**
 261  * ctpop64 - count the population of one bits in a 64-bit value.
 262  * @val: The value to search
 263  */
 264 static inline int ctpop64(uint64_t val)
 265 {
 266     return __builtin_popcountll(val);
 267 }
 268
 269 /**
 270  * revbit8 - reverse the bits in an 8-bit value.
 271  * @x: The value to modify.
 272  */
 273 static inline uint8_t revbit8(uint8_t x)
 274 {
 275     /* Assign the correct nibble position.  */
 276     x = ((x & 0xf0) >> 4)
 277       | ((x & 0x0f) << 4);
 278     /* Assign the correct bit position.  */
 279     x = ((x & 0x88) >> 3)
 280       | ((x & 0x44) >> 1)
 281       | ((x & 0x22) << 1)
 282       | ((x & 0x11) << 3);
 283     return x;
 284 }
 285
 286 /**
 287  * revbit16 - reverse the bits in a 16-bit value.
 288  * @x: The value to modify.
 289  */
 290 static inline uint16_t revbit16(uint16_t x)
 291 {
 292     /* Assign the correct byte position.  */
 293     x = bswap16(x);
 294     /* Assign the correct nibble position.  */
 295     x = ((x & 0xf0f0) >> 4)
 296       | ((x & 0x0f0f) << 4);
 297     /* Assign the correct bit position.  */
 298     x = ((x & 0x8888) >> 3)
 299       | ((x & 0x4444) >> 1)
 300       | ((x & 0x2222) << 1)
 301       | ((x & 0x1111) << 3);
 302     return x;
 303 }
 304
 305 /**
 306  * revbit32 - reverse the bits in a 32-bit value.
 307  * @x: The value to modify.
 308  */
 309 static inline uint32_t revbit32(uint32_t x)
 310 {
 311     /* Assign the correct byte position.  */
 312     x = bswap32(x);
 313     /* Assign the correct nibble position.  */
 314     x = ((x & 0xf0f0f0f0u) >> 4)
 315       | ((x & 0x0f0f0f0fu) << 4);
 316     /* Assign the correct bit position.  */
 317     x = ((x & 0x88888888u) >> 3)
 318       | ((x & 0x44444444u) >> 1)
 319       | ((x & 0x22222222u) << 1)
 320       | ((x & 0x11111111u) << 3);
 321     return x;
 322 }
 323
 324 /**
 325  * revbit64 - reverse the bits in a 64-bit value.
 326  * @x: The value to modify.
 327  */
 328 static inline uint64_t revbit64(uint64_t x)
 329 {
 330     /* Assign the correct byte position.  */
 331     x = bswap64(x);
 332     /* Assign the correct nibble position.  */
 333     x = ((x & 0xf0f0f0f0f0f0f0f0ull) >> 4)
 334       | ((x & 0x0f0f0f0f0f0f0f0full) << 4);
 335     /* Assign the correct bit position.  */
 336     x = ((x & 0x8888888888888888ull) >> 3)
 337       | ((x & 0x4444444444444444ull) >> 1)
 338       | ((x & 0x2222222222222222ull) << 1)
 339       | ((x & 0x1111111111111111ull) << 3);
 340     return x;
 341 }
 342
 343 /* Host type specific sizes of these routines.  */
 344
 345 #if ULONG_MAX == UINT32_MAX
 346 # define clzl   clz32
 347 # define ctzl   ctz32
 348 # define clol   clo32
 349 # define ctol   cto32
 350 # define ctpopl ctpop32
 351 # define revbitl revbit32
 352 #elif ULONG_MAX == UINT64_MAX
 353 # define clzl   clz64
 354 # define ctzl   ctz64
 355 # define clol   clo64
 356 # define ctol   cto64
 357 # define ctpopl ctpop64
 358 # define revbitl revbit64
 359 #else
 360 # error Unknown sizeof long
 361 #endif
 362
 363 static inline bool is_power_of_2(uint64_t value)
 364 {
 365     if (!value) {
 366         return false;
 367     }
 368
 369     return !(value & (value - 1));
 370 }
 371
 372 /**
 373  * Return @value rounded down to the nearest power of two or zero.
 374  */
 375 static inline uint64_t pow2floor(uint64_t value)
 376 {
 377     if (!value) {
 378         /* Avoid undefined shift by 64 */
 379         return 0;
 380     }
 381     return 0x8000000000000000ull >> clz64(value);
 382 }
 383
 384 /*
 385  * Return @value rounded up to the nearest power of two modulo 2^64.
 386  * This is *zero* for @value > 2^63, so be careful.
 387  */
 388 static inline uint64_t pow2ceil(uint64_t value)
 389 {
 390     int n = clz64(value - 1);
 391
 392     if (!n) {
 393         /*
 394          * @value - 1 has no leading zeroes, thus @value - 1 >= 2^63
 395          * Therefore, either @value == 0 or @value > 2^63.
 396          * If it's 0, return 1, else return 0.
 397          */
 398         return !value;
 399     }
 400     return 0x8000000000000000ull >> (n - 1);
 401 }
 402
 403 /**
 404  * urshift - 128-bit Unsigned Right Shift.
 405  * @plow: in/out - lower 64-bit integer.
 406  * @phigh: in/out - higher 64-bit integer.
 407  * @shift: in - bytes to shift, between 0 and 127.
 408  *
 409  * Result is zero-extended and stored in plow/phigh, which are
 410  * input/output variables. Shift values outside the range will
 411  * be mod to 128. In other words, the caller is responsible to
 412  * verify/assert both the shift range and plow/phigh pointers.
 413  */
 414 void urshift(uint64_t *plow, uint64_t *phigh, int32_t shift);
 415
 416 /**
 417  * ulshift - 128-bit Unsigned Left Shift.
 418  * @plow: in/out - lower 64-bit integer.
 419  * @phigh: in/out - higher 64-bit integer.
 420  * @shift: in - bytes to shift, between 0 and 127.
 421  * @overflow: out - true if any 1-bit is shifted out.
 422  *
 423  * Result is zero-extended and stored in plow/phigh, which are
 424  * input/output variables. Shift values outside the range will
 425  * be mod to 128. In other words, the caller is responsible to
 426  * verify/assert both the shift range and plow/phigh pointers.
 427  */
 428 void ulshift(uint64_t *plow, uint64_t *phigh, int32_t shift, bool *overflow);
 429
 430 #endif