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tcg-i386: Tidy lea. 

Implement full modrm+sib addressing mode processing.
Use that in qemu_ld/st to output the LEA.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
master
Richard Henderson 2010-05-21 08:30:33 -07:00 committed by Aurelien Jarno
parent b3e66df71a
commit 34a6d0b7fc
1 changed files with 61 additions and 32 deletions
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93
tcg/i386/tcg-target.c
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@ -174,6 +174,7 @@ static inline int tcg_target_const_match(tcg_target_long val,
#define OPC_JCC_short (0x70) /* ... plus condition code */
#define OPC_JMP_long (0xe9)
#define OPC_JMP_short (0xeb)
#define OPC_LEA (0x8d)
#define OPC_MOVB_EvGv (0x88) /* stores, more or less */
#define OPC_MOVL_EvGv (0x89) /* stores, more or less */
#define OPC_MOVL_GvEv (0x8b) /* loads, more or less */
@ -272,40 +273,70 @@ static inline void tcg_out_modrm(TCGContext *s, int opc, int r, int rm)
tcg_out8(s, 0xc0 | (r << 3) | rm);
}
/* rm == -1 means no register index */
static inline void tcg_out_modrm_offset(TCGContext *s, int opc, int r, int rm,
int32_t offset)
/* Output an opcode with a full "rm + (index<<shift) + offset" address mode.
We handle either RM and INDEX missing with a -1 value. */
static void tcg_out_modrm_sib_offset(TCGContext *s, int opc, int r, int rm,
int index, int shift, int32_t offset)
{
tcg_out_opc(s, opc);
if (rm == -1) {
tcg_out8(s, 0x05 | (r << 3));
int mod, len;
if (index == -1 && rm == -1) {
/* Absolute address. */
tcg_out_opc(s, opc);
tcg_out8(s, (r << 3) | 5);
tcg_out32(s, offset);
return;
}
tcg_out_opc(s, opc);
/* Find the length of the immediate addend. Note that the encoding
that would be used for (%ebp) indicates absolute addressing. */
if (rm == -1) {
mod = 0, len = 4, rm = 5;
} else if (offset == 0 && rm != TCG_REG_EBP) {
if (rm == TCG_REG_ESP) {
tcg_out8(s, 0x04 | (r << 3));
tcg_out8(s, 0x24);
} else {
tcg_out8(s, 0x00 | (r << 3) | rm);
}
} else if ((int8_t)offset == offset) {
if (rm == TCG_REG_ESP) {
tcg_out8(s, 0x44 | (r << 3));
tcg_out8(s, 0x24);
} else {
tcg_out8(s, 0x40 | (r << 3) | rm);
}
tcg_out8(s, offset);
mod = 0, len = 0;
} else if (offset == (int8_t)offset) {
mod = 0x40, len = 1;
} else {
if (rm == TCG_REG_ESP) {
tcg_out8(s, 0x84 | (r << 3));
tcg_out8(s, 0x24);
mod = 0x80, len = 4;
}
/* Use a single byte MODRM format if possible. Note that the encoding
that would be used for %esp is the escape to the two byte form. */
if (index == -1 && rm != TCG_REG_ESP) {
/* Single byte MODRM format. */
tcg_out8(s, mod | (r << 3) | rm);
} else {
/* Two byte MODRM+SIB format. */
/* Note that the encoding that would place %esp into the index
field indicates no index register. */
if (index == -1) {
index = 4;
} else {
tcg_out8(s, 0x80 | (r << 3) | rm);
assert(index != TCG_REG_ESP);
}
tcg_out8(s, mod | (r << 3) | 4);
tcg_out8(s, (shift << 6) | (index << 3) | rm);
}
if (len == 1) {
tcg_out8(s, offset);
} else if (len == 4) {
tcg_out32(s, offset);
}
}
/* rm == -1 means no register index */
static inline void tcg_out_modrm_offset(TCGContext *s, int opc, int r, int rm,
int32_t offset)
{
tcg_out_modrm_sib_offset(s, opc, r, rm, -1, 0, offset);
}
/* Generate dest op= src. Uses the same ARITH_* codes as tgen_arithi. */
static inline void tgen_arithr(TCGContext *s, int subop, int dest, int src)
{
@ -710,10 +741,9 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
tgen_arithi(s, ARITH_AND, r0, TARGET_PAGE_MASK | ((1 << s_bits) - 1), 0);
tgen_arithi(s, ARITH_AND, r1, (CPU_TLB_SIZE - 1) << CPU_TLB_ENTRY_BITS, 0);
tcg_out_opc(s, 0x8d); /* lea offset(r1, %ebp), r1 */
tcg_out8(s, 0x80 | (r1 << 3) | 0x04);
tcg_out8(s, (5 << 3) | r1);
tcg_out32(s, offsetof(CPUState, tlb_table[mem_index][0].addr_read));
tcg_out_modrm_sib_offset(s, OPC_LEA, r1, TCG_AREG0, r1, 0,
offsetof(CPUState,
tlb_table[mem_index][0].addr_read));
/* cmp 0(r1), r0 */
tcg_out_modrm_offset(s, OPC_CMP_GvEv, r0, r1, 0);
@ -903,10 +933,9 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args,
tgen_arithi(s, ARITH_AND, r0, TARGET_PAGE_MASK | ((1 << s_bits) - 1), 0);
tgen_arithi(s, ARITH_AND, r1, (CPU_TLB_SIZE - 1) << CPU_TLB_ENTRY_BITS, 0);
tcg_out_opc(s, 0x8d); /* lea offset(r1, %ebp), r1 */
tcg_out8(s, 0x80 | (r1 << 3) | 0x04);
tcg_out8(s, (5 << 3) | r1);
tcg_out32(s, offsetof(CPUState, tlb_table[mem_index][0].addr_write));
tcg_out_modrm_sib_offset(s, OPC_LEA, r1, TCG_AREG0, r1, 0,
offsetof(CPUState,
tlb_table[mem_index][0].addr_write));
/* cmp 0(r1), r0 */
tcg_out_modrm_offset(s, OPC_CMP_GvEv, r0, r1, 0);