Archipelago » qemu

/*

 *  M68K helper routines

 *

 *  Copyright (c) 2007 CodeSourcery

 *

 * 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 "exec.h"

#include "helpers.h"

#if defined(CONFIG_USER_ONLY)

void do_interrupt(int is_hw)

{

    env->exception_index = -1;

}

#else

extern int semihosting_enabled;

#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_m68k_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;

}

static void do_rte(void)

{

    uint32_t sp;

    uint32_t fmt;

    sp = env->aregs[7];

    fmt = ldl_kernel(sp);

    env->pc = ldl_kernel(sp + 4);

    sp |= (fmt >> 28) & 3;

    env->sr = fmt & 0xffff;

    m68k_switch_sp(env);

    env->aregs[7] = sp + 8;

}

void do_interrupt(int is_hw)

{

    uint32_t sp;

    uint32_t fmt;

    uint32_t retaddr;

    uint32_t vector;

    fmt = 0;

    retaddr = env->pc;

    if (!is_hw) {

        switch (env->exception_index) {

        case EXCP_RTE:

            /* Return from an exception.  */

            do_rte();

            return;

        case EXCP_HALT_INSN:

            if (semihosting_enabled

                    && (env->sr & SR_S) != 0

                    && (env->pc & 3) == 0

                    && lduw_code(env->pc - 4) == 0x4e71

                    && ldl_code(env->pc) == 0x4e7bf000) {

                env->pc += 4;

                do_m68k_semihosting(env, env->dregs[0]);

                return;

            }

            env->halted = 1;

            env->exception_index = EXCP_HLT;

            cpu_loop_exit();

            return;

        }

        if (env->exception_index >= EXCP_TRAP0

            && env->exception_index <= EXCP_TRAP15) {

            /* Move the PC after the trap instruction.  */

            retaddr += 2;

        }

    }

    vector = env->exception_index << 2;

    sp = env->aregs[7];

    fmt |= 0x40000000;

    fmt |= (sp & 3) << 28;

    fmt |= vector << 16;

    fmt |= env->sr;

    env->sr |= SR_S;

    if (is_hw) {

        env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);

        env->sr &= ~SR_M;

    }

    m68k_switch_sp(env);

    /* ??? This could cause MMU faults.  */

    sp &= ~3;

    sp -= 4;

    stl_kernel(sp, retaddr);

    sp -= 4;

    stl_kernel(sp, fmt);

    env->aregs[7] = sp;

    /* Jump to vector.  */

    env->pc = ldl_kernel(env->vbr + vector);

}

#endif

static void raise_exception(int tt)

{

    env->exception_index = tt;

    cpu_loop_exit();

}

void HELPER(raise_exception)(uint32_t tt)

{

    raise_exception(tt);

}

void HELPER(divu)(CPUState *env, uint32_t word)

{

    uint32_t num;

    uint32_t den;

    uint32_t quot;

    uint32_t rem;

    uint32_t flags;

    num = env->div1;

    den = env->div2;

    /* ??? This needs to make sure the throwing location is accurate.  */

    if (den == 0)

        raise_exception(EXCP_DIV0);

    quot = num / den;

    rem = num % den;

    flags = 0;

    /* Avoid using a PARAM1 of zero.  This breaks dyngen because it uses

       the address of a symbol, and gcc knows symbols can't have address

       zero.  */

    if (word && quot > 0xffff)

        flags |= CCF_V;

    if (quot == 0)

        flags |= CCF_Z;

    else if ((int32_t)quot < 0)

        flags |= CCF_N;

    env->div1 = quot;

    env->div2 = rem;

    env->cc_dest = flags;

}

void HELPER(divs)(CPUState *env, uint32_t word)

{

    int32_t num;

    int32_t den;

    int32_t quot;

    int32_t rem;

    int32_t flags;

    num = env->div1;

    den = env->div2;

    if (den == 0)

        raise_exception(EXCP_DIV0);

    quot = num / den;

    rem = num % den;

    flags = 0;

    if (word && quot != (int16_t)quot)

        flags |= CCF_V;

    if (quot == 0)

        flags |= CCF_Z;

    else if (quot < 0)

        flags |= CCF_N;

    env->div1 = quot;

    env->div2 = rem;

    env->cc_dest = flags;

}