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 "qemu/host-utils.h"
  29
  30 //#define DEBUG_MULDIV
  31
  32 /* Long integer helpers */
  33 #if !defined(__x86_64__)
  34 static 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
  43 static void neg128 (uint64_t *plow, uint64_t *phigh)
  44 {
  45     *plow = ~*plow;
  46     *phigh = ~*phigh;
  47     add128(plow, phigh, 1, 0);
  48 }
  49
  50 static 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 */
  76 void 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 */
  86 void 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__) */