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