Archipelago » qemu

/*

 *  i386 emulator main execution loop

 * 

 *  Copyright (c) 2003 Fabrice Bellard

 *

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

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program 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 General Public License for more details.

 *

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

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

#include "exec-i386.h"

#define DEBUG_EXEC

#define DEBUG_FLUSH

/* main execution loop */

/* maximum total translate dcode allocated */

#define CODE_GEN_BUFFER_SIZE     (2048 * 1024)

//#define CODE_GEN_BUFFER_SIZE     (128 * 1024)

#define CODE_GEN_MAX_SIZE        65536

#define CODE_GEN_ALIGN           16 /* must be >= of the size of a icache line */

/* threshold to flush the translated code buffer */

#define CODE_GEN_BUFFER_MAX_SIZE (CODE_GEN_BUFFER_SIZE - CODE_GEN_MAX_SIZE)

#define CODE_GEN_MAX_BLOCKS    (CODE_GEN_BUFFER_SIZE / 64)

#define CODE_GEN_HASH_BITS     15

#define CODE_GEN_HASH_SIZE     (1 << CODE_GEN_HASH_BITS)

typedef struct TranslationBlock {

    unsigned long pc;   /* simulated PC corresponding to this block */

    uint8_t *tc_ptr;    /* pointer to the translated code */

    struct TranslationBlock *hash_next; /* next matching block */

} TranslationBlock;

TranslationBlock tbs[CODE_GEN_MAX_BLOCKS];

TranslationBlock *tb_hash[CODE_GEN_HASH_SIZE];

int nb_tbs;

uint8_t code_gen_buffer[CODE_GEN_BUFFER_SIZE];

uint8_t *code_gen_ptr;

#ifdef DEBUG_EXEC

static const char *cc_op_str[] = {

    "DYNAMIC",

    "EFLAGS",

    "MUL",

    "ADDB",

    "ADDW",

    "ADDL",

    "ADCB",

    "ADCW",

    "ADCL",

    "SUBB",

    "SUBW",

    "SUBL",

    "SBBB",

    "SBBW",

    "SBBL",

    "LOGICB",

    "LOGICW",

    "LOGICL",

    "INCB",

    "INCW",

    "INCL",

    "DECB",

    "DECW",

    "DECL",

    "SHLB",

    "SHLW",

    "SHLL",

    "SARB",

    "SARW",

    "SARL",

};

static void cpu_x86_dump_state(void)

{

    int eflags;

    eflags = cc_table[CC_OP].compute_all();

    eflags |= (DF & DIRECTION_FLAG);

    fprintf(logfile, 

            "EAX=%08x EBX=%08X ECX=%08x EDX=%08x\n"

            "ESI=%08x EDI=%08X EBP=%08x ESP=%08x\n"

            "CCS=%08x CCD=%08x CCO=%-8s EFL=%c%c%c%c%c%c%c\n",

            env->regs[R_EAX], env->regs[R_EBX], env->regs[R_ECX], env->regs[R_EDX], 

            env->regs[R_ESI], env->regs[R_EDI], env->regs[R_EBP], env->regs[R_ESP], 

            env->cc_src, env->cc_dst, cc_op_str[env->cc_op],

            eflags & DIRECTION_FLAG ? 'D' : '-',

            eflags & CC_O ? 'O' : '-',

            eflags & CC_S ? 'S' : '-',

            eflags & CC_Z ? 'Z' : '-',

            eflags & CC_A ? 'A' : '-',

            eflags & CC_P ? 'P' : '-',

            eflags & CC_C ? 'C' : '-'

            );

#if 1

    fprintf(logfile, "ST0=%f ST1=%f ST2=%f ST3=%f\n", 

            (double)ST0, (double)ST1, (double)ST(2), (double)ST(3));

#endif

}

#endif

void cpu_x86_tblocks_init(void)

{

    if (!code_gen_ptr) {

        code_gen_ptr = code_gen_buffer;

    }

}

/* flush all the translation blocks */

static void tb_flush(void)

{

    int i;

#ifdef DEBUG_FLUSH

    printf("gemu: flush code_size=%d nb_tbs=%d avg_tb_size=%d\n", 

           code_gen_ptr - code_gen_buffer, 

           nb_tbs, 

           (code_gen_ptr - code_gen_buffer) / nb_tbs);

#endif

    nb_tbs = 0;

    for(i = 0;i < CODE_GEN_HASH_SIZE; i++)

        tb_hash[i] = NULL;

    code_gen_ptr = code_gen_buffer;

    /* XXX: flush processor icache at this point */

}

/* find a translation block in the translation cache. If not found,

   allocate a new one */

static inline TranslationBlock *tb_find_and_alloc(unsigned long pc)

{

    TranslationBlock **ptb, *tb;

    unsigned int h;

    h = pc & (CODE_GEN_HASH_SIZE - 1);

    ptb = &tb_hash[h];

    for(;;) {

        tb = *ptb;

        if (!tb)

            break;

        if (tb->pc == pc)

            return tb;

        ptb = &tb->hash_next;

    }

    if (nb_tbs >= CODE_GEN_MAX_BLOCKS || 

        (code_gen_ptr - code_gen_buffer) >= CODE_GEN_BUFFER_MAX_SIZE)

        tb_flush();

    tb = &tbs[nb_tbs++];

    *ptb = tb;

    tb->pc = pc;

    tb->tc_ptr = NULL;

    tb->hash_next = NULL;

    return tb;

}

int cpu_x86_exec(CPUX86State *env1)

{

    int saved_T0, saved_T1, saved_A0;

    CPUX86State *saved_env;

    int code_gen_size, ret;

    void (*gen_func)(void);

    TranslationBlock *tb;

    uint8_t *tc_ptr;

    /* first we save global registers */

    saved_T0 = T0;

    saved_T1 = T1;

    saved_A0 = A0;

    saved_env = env;

    env = env1;

    /* prepare setjmp context for exception handling */

    if (setjmp(env->jmp_env) == 0) {

        for(;;) {

#ifdef DEBUG_EXEC

            if (loglevel) {

                cpu_x86_dump_state();

            }

#endif

            tb = tb_find_and_alloc((unsigned long)env->pc);

            tc_ptr = tb->tc_ptr;

            if (!tb->tc_ptr) {

                /* if no translated code available, then translate it now */

                tc_ptr = code_gen_ptr;

                cpu_x86_gen_code(code_gen_ptr, CODE_GEN_MAX_SIZE, 

                                 &code_gen_size, (uint8_t *)env->pc);

                tb->tc_ptr = tc_ptr;

                code_gen_ptr = (void *)(((unsigned long)code_gen_ptr + code_gen_size + CODE_GEN_ALIGN - 1) & ~(CODE_GEN_ALIGN - 1));

            }

            /* execute the generated code */

            gen_func = (void *)tc_ptr;

            gen_func();

        }

    }

    ret = env->exception_index;

    /* restore global registers */

    T0 = saved_T0;

    T1 = saved_T1;

    A0 = saved_A0;

    env = saved_env;

    return ret;

}