Archipelago » qemu

/*

 *  Microblaze helper routines.

 *

 *  Copyright (c) 2009 Edgar E. Iglesias <edgar.iglesias@gmail.com>.

 *

 * 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, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 USA

 */

#include <assert.h>

#include "exec.h"

#include "helper.h"

#include "host-utils.h"

#define D(x)

#if !defined(CONFIG_USER_ONLY)

#define MMUSUFFIX _mmu

#define SHIFT 0

#include "softmmu_template.h"

#define SHIFT 1

#include "softmmu_template.h"

#define SHIFT 2

#include "softmmu_template.h"

#define SHIFT 3

#include "softmmu_template.h"

/* Try to fill the TLB and return an exception if error. If retaddr is

   NULL, it means that the function was called in C code (i.e. not

   from generated code or from helper.c) */

/* XXX: fix it to restore all registers */

void tlb_fill (target_ulong addr, int is_write, int mmu_idx, void *retaddr)

{

    TranslationBlock *tb;

    CPUState *saved_env;

    unsigned long pc;

    int ret;

    /* XXX: hack to restore env in all cases, even if not called from

       generated code */

    saved_env = env;

    env = cpu_single_env;

    ret = cpu_mb_handle_mmu_fault(env, addr, is_write, mmu_idx, 1);

    if (unlikely(ret)) {

        if (retaddr) {

            /* now we have a real cpu fault */

            pc = (unsigned long)retaddr;

            tb = tb_find_pc(pc);

            if (tb) {

                /* the PC is inside the translated code. It means that we have

                   a virtual CPU fault */

                cpu_restore_state(tb, env, pc, NULL);

            }

        }

        cpu_loop_exit();

    }

    env = saved_env;

}

#endif

void helper_raise_exception(uint32_t index)

{

    env->exception_index = index;

    cpu_loop_exit();

}

void helper_debug(void)

{

    int i;

    qemu_log("PC=%8.8x\n", env->sregs[SR_PC]);

    for (i = 0; i < 32; i++) {

        qemu_log("r%2.2d=%8.8x ", i, env->regs[i]);

        if ((i + 1) % 4 == 0)

            qemu_log("\n");

    }

    qemu_log("\n\n");

}

static inline uint32_t compute_carry(uint32_t a, uint32_t b, uint32_t cin)

{

    uint32_t cout = 0;

    if ((b == ~0) && cin)

        cout = 1;

    else if ((~0 - a) < (b + cin))

        cout = 1;

    return cout;

}

uint32_t helper_cmp(uint32_t a, uint32_t b)

{

    uint32_t t;

    t = b + ~a + 1;

    if ((b & 0x80000000) ^ (a & 0x80000000))

        t = (t & 0x7fffffff) | (b & 0x80000000);

    return t;

}

uint32_t helper_cmpu(uint32_t a, uint32_t b)

{

    uint32_t t;

    t = b + ~a + 1;

    if ((b & 0x80000000) ^ (a & 0x80000000))

        t = (t & 0x7fffffff) | (a & 0x80000000);

    return t;

}

uint32_t helper_addkc(uint32_t a, uint32_t b, uint32_t k, uint32_t c)

{

    uint32_t d, cf = 0, ncf;

    if (c)

        cf = env->sregs[SR_MSR] >> 31;

    assert(cf == 0 || cf == 1);

    d = a + b + cf;

    if (!k) {

        ncf = compute_carry(a, b, cf);

        assert(ncf == 0 || ncf == 1);

        if (ncf)

            env->sregs[SR_MSR] |= MSR_C | MSR_CC;

        else

            env->sregs[SR_MSR] &= ~(MSR_C | MSR_CC);

    }

    D(qemu_log("%x = %x + %x cf=%d ncf=%d k=%d c=%d\n",

               d, a, b, cf, ncf, k, c));

    return d;

}

uint32_t helper_subkc(uint32_t a, uint32_t b, uint32_t k, uint32_t c)

{

    uint32_t d, cf = 1, ncf;

    if (c)

        cf = env->sregs[SR_MSR] >> 31; 

    assert(cf == 0 || cf == 1);

    d = b + ~a + cf;

    if (!k) {

        ncf = compute_carry(b, ~a, cf);

        assert(ncf == 0 || ncf == 1);

        if (ncf)

            env->sregs[SR_MSR] |= MSR_C | MSR_CC;

        else

            env->sregs[SR_MSR] &= ~(MSR_C | MSR_CC);

    }

    D(qemu_log("%x = %x + %x cf=%d ncf=%d k=%d c=%d\n",

               d, a, b, cf, ncf, k, c));

    return d;

}

static inline int div_prepare(uint32_t a, uint32_t b)

{

    if (b == 0) {

        env->sregs[SR_MSR] |= MSR_DZ;

        /* FIXME: Raise the div by zero exception.  */

        return 0;

    }

    env->sregs[SR_MSR] &= ~MSR_DZ;

    return 1;

}

uint32_t helper_divs(uint32_t a, uint32_t b)

{

    if (!div_prepare(a, b))

        return 0;

    return (int32_t)a / (int32_t)b;

}

uint32_t helper_divu(uint32_t a, uint32_t b)

{

    if (!div_prepare(a, b))

        return 0;

    return a / b;

}

uint32_t helper_pcmpbf(uint32_t a, uint32_t b)

{

    unsigned int i;

    uint32_t mask = 0xff000000;

    for (i = 0; i < 4; i++) {

        if ((a & mask) == (b & mask))

            return i + 1;

        mask >>= 8;

    }

    return 0;

}

#if !defined(CONFIG_USER_ONLY)

/* Writes/reads to the MMU's special regs end up here.  */

uint32_t helper_mmu_read(uint32_t rn)

{

    return mmu_read(env, rn);

}

void helper_mmu_write(uint32_t rn, uint32_t v)

{

    mmu_write(env, rn, v);

}

#endif