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