Archipelago » qemu

/*

 * Utility compute operations used by translated code.

 *

 * Copyright (c) 2003 Fabrice Bellard

 * Copyright (c) 2007 Aurelien Jarno

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include <stdlib.h>

#include <stdint.h>

#include "qemu/host-utils.h"

//#define DEBUG_MULDIV

/* Long integer helpers */

#if !defined(__x86_64__)

static void add128 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)

{

    *plow += a;

    /* carry test */

    if (*plow < a)

        (*phigh)++;

    *phigh += b;

}

static void neg128 (uint64_t *plow, uint64_t *phigh)

{

    *plow = ~*plow;

    *phigh = ~*phigh;

    add128(plow, phigh, 1, 0);

}

static void mul64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)

{

    uint32_t a0, a1, b0, b1;

    uint64_t v;

    a0 = a;

    a1 = a >> 32;

    b0 = b;

    b1 = b >> 32;

    v = (uint64_t)a0 * (uint64_t)b0;

    *plow = v;

    *phigh = 0;

    v = (uint64_t)a0 * (uint64_t)b1;

    add128(plow, phigh, v << 32, v >> 32);

    v = (uint64_t)a1 * (uint64_t)b0;

    add128(plow, phigh, v << 32, v >> 32);

    v = (uint64_t)a1 * (uint64_t)b1;

    *phigh += v;

}

/* Unsigned 64x64 -> 128 multiplication */

void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)

{

    mul64(plow, phigh, a, b);

#if defined(DEBUG_MULDIV)

    printf("mulu64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",

           a, b, *phigh, *plow);

#endif

}

/* Signed 64x64 -> 128 multiplication */

void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)

{

    int sa, sb;

    sa = (a < 0);

    if (sa)

        a = -a;

    sb = (b < 0);

    if (sb)

        b = -b;

    mul64(plow, phigh, a, b);

    if (sa ^ sb) {

        neg128(plow, phigh);

    }

#if defined(DEBUG_MULDIV)

    printf("muls64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",

           a, b, *phigh, *plow);

#endif

}

#endif /* !defined(__x86_64__) */