host-utils.c

   1 /*
   2  * Utility compute operations used by translated code.
   3  *
   4  * Copyright (c) 2003 Fabrice Bellard
   5  * Copyright (c) 2007 Aurelien Jarno
   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 #include "vl.h"
  27
  28 //#define DEBUG_MULDIV
  29
  30 /* Long integer helpers */
  31 static void add128 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
  32 {
  33     *plow += a;
  34     /* carry test */
  35     if (*plow < a)
  36         (*phigh)++;
  37     *phigh += b;
  38 }
  39
  40 static void neg128 (uint64_t *plow, uint64_t *phigh)
  41 {
  42     *plow = ~*plow;
  43     *phigh = ~*phigh;
  44     add128(plow, phigh, 1, 0);
  45 }
  46
  47 static void mul64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
  48 {
  49     uint32_t a0, a1, b0, b1;
  50     uint64_t v;
  51
  52     a0 = a;
  53     a1 = a >> 32;
  54
  55     b0 = b;
  56     b1 = b >> 32;
  57
  58     v = (uint64_t)a0 * (uint64_t)b0;
  59     *plow = v;
  60     *phigh = 0;
  61
  62     v = (uint64_t)a0 * (uint64_t)b1;
  63     add128(plow, phigh, v << 32, v >> 32);
  64
  65     v = (uint64_t)a1 * (uint64_t)b0;
  66     add128(plow, phigh, v << 32, v >> 32);
  67
  68     v = (uint64_t)a1 * (uint64_t)b1;
  69     *phigh += v;
  70 }
  71
  72
  73 /* Unsigned 64x64 -> 128 multiplication */
  74 void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
  75 {
  76 #if defined(__x86_64__)
  77     __asm__ ("mul %0\n\t"
  78              : "=d" (*phigh), "=a" (*plow)
  79              : "a" (a), "0" (b));
  80 #else
  81     mul64(plow, phigh, a, b);
  82 #endif
  83 #if defined(DEBUG_MULDIV)
  84     printf("mulu64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",
  85            a, b, *phigh, *plow);
  86 #endif
  87 }
  88
  89 /* Signed 64x64 -> 128 multiplication */
  90 void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)
  91 {
  92 #if defined(__x86_64__)
  93     __asm__ ("imul %0\n\t"
  94              : "=d" (*phigh), "=a" (*plow)
  95              : "a" (a), "0" (b));
  96 #else
  97     int sa, sb;
  98
  99     sa = (a < 0);
 100     if (sa)
 101         a = -a;
 102     sb = (b < 0);
 103     if (sb)
 104         b = -b;
 105     mul64(plow, phigh, a, b);
 106     if (sa ^ sb) {
 107         neg128(plow, phigh);
 108     }
 109 #endif
 110 #if defined(DEBUG_MULDIV)
 111     printf("muls64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",
 112            a, b, *phigh, *plow);
 113 #endif
 114 }