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