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qemu/exec-i386.c

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/*
* 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 */
unsigned int flags; /* flags defining in which context the code was generated */
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,
unsigned int flags)
{
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 && tb->flags == flags)
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->flags = flags;
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;
unsigned int flags;
/* 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
/* we compute the CPU state. We assume it will not
change during the whole generated block. */
flags = env->seg_cache[R_CS].seg_32bit << GEN_FLAG_CODE32_SHIFT;
flags |= (((unsigned long)env->seg_cache[R_DS].base |
(unsigned long)env->seg_cache[R_ES].base |
(unsigned long)env->seg_cache[R_SS].base) != 0) <<
GEN_FLAG_ADDSEG_SHIFT;
tb = tb_find_and_alloc((unsigned long)env->pc, flags);
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, flags);
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;
}
void cpu_x86_load_seg(CPUX86State *s, int seg_reg, int selector)
{
CPUX86State *saved_env;
saved_env = env;
env = s;
load_seg(seg_reg, selector);
env = saved_env;
}
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