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