File:  [Qemu by Fabrice Bellard] / qemu / host-utils.c
Revision 1.1.1.1 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 16:47:07 2018 UTC (2 years, 4 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu0111, qemu0110, qemu0105, qemu0104, qemu0103, qemu0102, qemu0101, qemu0100, qemu0091, HEAD
qemu 0.9.1

    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__) */

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