Archipelago » qemu

/*

 *  x86 integer helpers

 *

 *  Copyright (c) 2003 Fabrice Bellard

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 */

#include "cpu.h"

#include "host-utils.h"

#include "helper.h"

//#define DEBUG_MULDIV

/* modulo 9 table */

static const uint8_t rclb_table[32] = {

    0, 1, 2, 3, 4, 5, 6, 7,

    8, 0, 1, 2, 3, 4, 5, 6,

    7, 8, 0, 1, 2, 3, 4, 5,

    6, 7, 8, 0, 1, 2, 3, 4,

};

/* modulo 17 table */

static const uint8_t rclw_table[32] = {

    0, 1, 2, 3, 4, 5, 6, 7,

    8, 9, 10, 11, 12, 13, 14, 15,

    16, 0, 1, 2, 3, 4, 5, 6,

    7, 8, 9, 10, 11, 12, 13, 14,

};

/* division, flags are undefined */

void helper_divb_AL(CPUX86State *env, target_ulong t0)

{

    unsigned int num, den, q, r;

    num = (EAX & 0xffff);

    den = (t0 & 0xff);

    if (den == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q = (num / den);

    if (q > 0xff) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q &= 0xff;

    r = (num % den) & 0xff;

    EAX = (EAX & ~0xffff) | (r << 8) | q;

}

void helper_idivb_AL(CPUX86State *env, target_ulong t0)

{

    int num, den, q, r;

    num = (int16_t)EAX;

    den = (int8_t)t0;

    if (den == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q = (num / den);

    if (q != (int8_t)q) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q &= 0xff;

    r = (num % den) & 0xff;

    EAX = (EAX & ~0xffff) | (r << 8) | q;

}

void helper_divw_AX(CPUX86State *env, target_ulong t0)

{

    unsigned int num, den, q, r;

    num = (EAX & 0xffff) | ((EDX & 0xffff) << 16);

    den = (t0 & 0xffff);

    if (den == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q = (num / den);

    if (q > 0xffff) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q &= 0xffff;

    r = (num % den) & 0xffff;

    EAX = (EAX & ~0xffff) | q;

    EDX = (EDX & ~0xffff) | r;

}

void helper_idivw_AX(CPUX86State *env, target_ulong t0)

{

    int num, den, q, r;

    num = (EAX & 0xffff) | ((EDX & 0xffff) << 16);

    den = (int16_t)t0;

    if (den == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q = (num / den);

    if (q != (int16_t)q) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q &= 0xffff;

    r = (num % den) & 0xffff;

    EAX = (EAX & ~0xffff) | q;

    EDX = (EDX & ~0xffff) | r;

}

void helper_divl_EAX(CPUX86State *env, target_ulong t0)

{

    unsigned int den, r;

    uint64_t num, q;

    num = ((uint32_t)EAX) | ((uint64_t)((uint32_t)EDX) << 32);

    den = t0;

    if (den == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q = (num / den);

    r = (num % den);

    if (q > 0xffffffff) {

        raise_exception(env, EXCP00_DIVZ);

    }

    EAX = (uint32_t)q;

    EDX = (uint32_t)r;

}

void helper_idivl_EAX(CPUX86State *env, target_ulong t0)

{

    int den, r;

    int64_t num, q;

    num = ((uint32_t)EAX) | ((uint64_t)((uint32_t)EDX) << 32);

    den = t0;

    if (den == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    q = (num / den);

    r = (num % den);

    if (q != (int32_t)q) {

        raise_exception(env, EXCP00_DIVZ);

    }

    EAX = (uint32_t)q;

    EDX = (uint32_t)r;

}

/* bcd */

/* XXX: exception */

void helper_aam(CPUX86State *env, int base)

{

    int al, ah;

    al = EAX & 0xff;

    ah = al / base;

    al = al % base;

    EAX = (EAX & ~0xffff) | al | (ah << 8);

    CC_DST = al;

}

void helper_aad(CPUX86State *env, int base)

{

    int al, ah;

    al = EAX & 0xff;

    ah = (EAX >> 8) & 0xff;

    al = ((ah * base) + al) & 0xff;

    EAX = (EAX & ~0xffff) | al;

    CC_DST = al;

}

void helper_aaa(CPUX86State *env)

{

    int icarry;

    int al, ah, af;

    int eflags;

    eflags = cpu_cc_compute_all(env, CC_OP);

    af = eflags & CC_A;

    al = EAX & 0xff;

    ah = (EAX >> 8) & 0xff;

    icarry = (al > 0xf9);

    if (((al & 0x0f) > 9) || af) {

        al = (al + 6) & 0x0f;

        ah = (ah + 1 + icarry) & 0xff;

        eflags |= CC_C | CC_A;

    } else {

        eflags &= ~(CC_C | CC_A);

        al &= 0x0f;

    }

    EAX = (EAX & ~0xffff) | al | (ah << 8);

    CC_SRC = eflags;

}

void helper_aas(CPUX86State *env)

{

    int icarry;

    int al, ah, af;

    int eflags;

    eflags = cpu_cc_compute_all(env, CC_OP);

    af = eflags & CC_A;

    al = EAX & 0xff;

    ah = (EAX >> 8) & 0xff;

    icarry = (al < 6);

    if (((al & 0x0f) > 9) || af) {

        al = (al - 6) & 0x0f;

        ah = (ah - 1 - icarry) & 0xff;

        eflags |= CC_C | CC_A;

    } else {

        eflags &= ~(CC_C | CC_A);

        al &= 0x0f;

    }

    EAX = (EAX & ~0xffff) | al | (ah << 8);

    CC_SRC = eflags;

}

void helper_daa(CPUX86State *env)

{

    int old_al, al, af, cf;

    int eflags;

    eflags = cpu_cc_compute_all(env, CC_OP);

    cf = eflags & CC_C;

    af = eflags & CC_A;

    old_al = al = EAX & 0xff;

    eflags = 0;

    if (((al & 0x0f) > 9) || af) {

        al = (al + 6) & 0xff;

        eflags |= CC_A;

    }

    if ((old_al > 0x99) || cf) {

        al = (al + 0x60) & 0xff;

        eflags |= CC_C;

    }

    EAX = (EAX & ~0xff) | al;

    /* well, speed is not an issue here, so we compute the flags by hand */

    eflags |= (al == 0) << 6; /* zf */

    eflags |= parity_table[al]; /* pf */

    eflags |= (al & 0x80); /* sf */

    CC_SRC = eflags;

}

void helper_das(CPUX86State *env)

{

    int al, al1, af, cf;

    int eflags;

    eflags = cpu_cc_compute_all(env, CC_OP);

    cf = eflags & CC_C;

    af = eflags & CC_A;

    al = EAX & 0xff;

    eflags = 0;

    al1 = al;

    if (((al & 0x0f) > 9) || af) {

        eflags |= CC_A;

        if (al < 6 || cf) {

            eflags |= CC_C;

        }

        al = (al - 6) & 0xff;

    }

    if ((al1 > 0x99) || cf) {

        al = (al - 0x60) & 0xff;

        eflags |= CC_C;

    }

    EAX = (EAX & ~0xff) | al;

    /* well, speed is not an issue here, so we compute the flags by hand */

    eflags |= (al == 0) << 6; /* zf */

    eflags |= parity_table[al]; /* pf */

    eflags |= (al & 0x80); /* sf */

    CC_SRC = eflags;

}

#ifdef TARGET_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);

}

/* return TRUE if overflow */

static int div64(uint64_t *plow, uint64_t *phigh, uint64_t b)

{

    uint64_t q, r, a1, a0;

    int i, qb, ab;

    a0 = *plow;

    a1 = *phigh;

    if (a1 == 0) {

        q = a0 / b;

        r = a0 % b;

        *plow = q;

        *phigh = r;

    } else {

        if (a1 >= b) {

            return 1;

        }

        /* XXX: use a better algorithm */

        for (i = 0; i < 64; i++) {

            ab = a1 >> 63;

            a1 = (a1 << 1) | (a0 >> 63);

            if (ab || a1 >= b) {

                a1 -= b;

                qb = 1;

            } else {

                qb = 0;

            }

            a0 = (a0 << 1) | qb;

        }

#if defined(DEBUG_MULDIV)

        printf("div: 0x%016" PRIx64 "%016" PRIx64 " / 0x%016" PRIx64

               ": q=0x%016" PRIx64 " r=0x%016" PRIx64 "\n",

               *phigh, *plow, b, a0, a1);

#endif

        *plow = a0;

        *phigh = a1;

    }

    return 0;

}

/* return TRUE if overflow */

static int idiv64(uint64_t *plow, uint64_t *phigh, int64_t b)

{

    int sa, sb;

    sa = ((int64_t)*phigh < 0);

    if (sa) {

        neg128(plow, phigh);

    }

    sb = (b < 0);

    if (sb) {

        b = -b;

    }

    if (div64(plow, phigh, b) != 0) {

        return 1;

    }

    if (sa ^ sb) {

        if (*plow > (1ULL << 63)) {

            return 1;

        }

        *plow = -*plow;

    } else {

        if (*plow >= (1ULL << 63)) {

            return 1;

        }

    }

    if (sa) {

        *phigh = -*phigh;

    }

    return 0;

}

void helper_mulq_EAX_T0(CPUX86State *env, target_ulong t0)

{

    uint64_t r0, r1;

    mulu64(&r0, &r1, EAX, t0);

    EAX = r0;

    EDX = r1;

    CC_DST = r0;

    CC_SRC = r1;

}

void helper_imulq_EAX_T0(CPUX86State *env, target_ulong t0)

{

    uint64_t r0, r1;

    muls64(&r0, &r1, EAX, t0);

    EAX = r0;

    EDX = r1;

    CC_DST = r0;

    CC_SRC = ((int64_t)r1 != ((int64_t)r0 >> 63));

}

target_ulong helper_imulq_T0_T1(CPUX86State *env, target_ulong t0,

                                target_ulong t1)

{

    uint64_t r0, r1;

    muls64(&r0, &r1, t0, t1);

    CC_DST = r0;

    CC_SRC = ((int64_t)r1 != ((int64_t)r0 >> 63));

    return r0;

}

void helper_divq_EAX(CPUX86State *env, target_ulong t0)

{

    uint64_t r0, r1;

    if (t0 == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    r0 = EAX;

    r1 = EDX;

    if (div64(&r0, &r1, t0)) {

        raise_exception(env, EXCP00_DIVZ);

    }

    EAX = r0;

    EDX = r1;

}

void helper_idivq_EAX(CPUX86State *env, target_ulong t0)

{

    uint64_t r0, r1;

    if (t0 == 0) {

        raise_exception(env, EXCP00_DIVZ);

    }

    r0 = EAX;

    r1 = EDX;

    if (idiv64(&r0, &r1, t0)) {

        raise_exception(env, EXCP00_DIVZ);

    }

    EAX = r0;

    EDX = r1;

}

#endif

/* bit operations */

target_ulong helper_bsf(target_ulong t0)

{

    int count;

    target_ulong res;

    res = t0;

    count = 0;

    while ((res & 1) == 0) {

        count++;

        res >>= 1;

    }

    return count;

}

target_ulong helper_lzcnt(target_ulong t0, int wordsize)

{

    int count;

    target_ulong res, mask;

    if (wordsize > 0 && t0 == 0) {

        return wordsize;

    }

    res = t0;

    count = TARGET_LONG_BITS - 1;

    mask = (target_ulong)1 << (TARGET_LONG_BITS - 1);

    while ((res & mask) == 0) {

        count--;

        res <<= 1;

    }

    if (wordsize > 0) {

        return wordsize - 1 - count;

    }

    return count;

}

target_ulong helper_bsr(target_ulong t0)

{

    return helper_lzcnt(t0, 0);

}

#define SHIFT 0

#include "shift_helper_template.h"

#undef SHIFT

#define SHIFT 1

#include "shift_helper_template.h"

#undef SHIFT

#define SHIFT 2

#include "shift_helper_template.h"

#undef SHIFT

#ifdef TARGET_X86_64

#define SHIFT 3

#include "shift_helper_template.h"

#undef SHIFT

#endif