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tcg-i386: Swap order of TLB hit and miss paths.

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Make fallthru be TLB hit and branch be TLB miss.  Doing this
both improves branch prediction and will allow further cleanup.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Richard Henderson 2010-05-21 09:03:02 -07:00 committed by Aurelien Jarno
parent be5a4eb7f0
commit 1a6dc1e406
1 changed files with 80 additions and 92 deletions
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160
tcg/i386/tcg-target.c
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@ -771,26 +771,21 @@ static void tcg_out_qemu_ld_direct(TCGContext *s, int datalo, int datahi,
static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
int opc)
{
int addr_reg, data_reg, data_reg2, r0, r1, mem_index, s_bits;
int addr_reg, addr_reg2 = 0;
int data_reg, data_reg2 = 0;
int r0, r1, mem_index, s_bits;
#if defined(CONFIG_SOFTMMU)
uint8_t *label1_ptr, *label2_ptr;
#endif
#if TARGET_LONG_BITS == 64
#if defined(CONFIG_SOFTMMU)
uint8_t *label3_ptr;
#endif
int addr_reg2;
uint8_t *label_ptr[3];
#endif
data_reg = *args++;
if (opc == 3)
if (opc == 3) {
data_reg2 = *args++;
else
data_reg2 = 0;
}
addr_reg = *args++;
#if TARGET_LONG_BITS == 64
if (TARGET_LONG_BITS == 64) {
addr_reg2 = *args++;
#endif
}
mem_index = *args;
s_bits = opc & 3;
@ -815,28 +810,42 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
tcg_out_mov(s, r0, addr_reg);
#if TARGET_LONG_BITS == 32
/* je label1 */
tcg_out8(s, OPC_JCC_short + JCC_JE);
label1_ptr = s->code_ptr;
s->code_ptr++;
#else
/* jne label3 */
/* jne label1 */
tcg_out8(s, OPC_JCC_short + JCC_JNE);
label3_ptr = s->code_ptr;
label_ptr[0] = s->code_ptr;
s->code_ptr++;
if (TARGET_LONG_BITS == 64) {
/* cmp 4(r1), addr_reg2 */
tcg_out_modrm_offset(s, OPC_CMP_GvEv, addr_reg2, r1, 4);
/* je label1 */
tcg_out8(s, OPC_JCC_short + JCC_JE);
label1_ptr = s->code_ptr;
/* jne label1 */
tcg_out8(s, OPC_JCC_short + JCC_JNE);
label_ptr[1] = s->code_ptr;
s->code_ptr++;
}
/* TLB Hit. */
/* add x(r1), r0 */
tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
offsetof(CPUTLBEntry, addend) -
offsetof(CPUTLBEntry, addr_read));
tcg_out_qemu_ld_direct(s, data_reg, data_reg2, r0, 0, opc);
/* jmp label2 */
tcg_out8(s, OPC_JMP_short);
label_ptr[2] = s->code_ptr;
s->code_ptr++;
/* label3: */
*label3_ptr = s->code_ptr - label3_ptr - 1;
#endif
/* TLB Miss. */
/* label1: */
*label_ptr[0] = s->code_ptr - label_ptr[0] - 1;
if (TARGET_LONG_BITS == 64) {
*label_ptr[1] = s->code_ptr - label_ptr[1] - 1;
}
/* XXX: move that code at the end of the TB */
#if TARGET_LONG_BITS == 32
@ -876,23 +885,8 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
break;
}
/* jmp label2 */
tcg_out8(s, OPC_JMP_short);
label2_ptr = s->code_ptr;
s->code_ptr++;
/* label1: */
*label1_ptr = s->code_ptr - label1_ptr - 1;
/* add x(r1), r0 */
tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
offsetof(CPUTLBEntry, addend) -
offsetof(CPUTLBEntry, addr_read));
tcg_out_qemu_ld_direct(s, data_reg, data_reg2, r0, 0, opc);
/* label2: */
*label2_ptr = s->code_ptr - label2_ptr - 1;
*label_ptr[2] = s->code_ptr - label_ptr[2] - 1;
#else
tcg_out_qemu_ld_direct(s, data_reg, data_reg2, addr_reg, GUEST_BASE, opc);
#endif
@ -955,27 +949,22 @@ static void tcg_out_qemu_st_direct(TCGContext *s, int datalo, int datahi,
static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args,
int opc)
{
int addr_reg, data_reg, data_reg2, r0, r1, mem_index, s_bits;
int addr_reg, addr_reg2 = 0;
int data_reg, data_reg2 = 0;
int r0, r1, mem_index, s_bits;
#if defined(CONFIG_SOFTMMU)
int stack_adjust;
uint8_t *label1_ptr, *label2_ptr;
#endif
#if TARGET_LONG_BITS == 64
#if defined(CONFIG_SOFTMMU)
uint8_t *label3_ptr;
#endif
int addr_reg2;
uint8_t *label_ptr[3];
#endif
data_reg = *args++;
if (opc == 3)
if (opc == 3) {
data_reg2 = *args++;
else
data_reg2 = 0;
}
addr_reg = *args++;
#if TARGET_LONG_BITS == 64
if (TARGET_LONG_BITS == 64) {
addr_reg2 = *args++;
#endif
}
mem_index = *args;
s_bits = opc;
@ -1001,28 +990,42 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args,
tcg_out_mov(s, r0, addr_reg);
#if TARGET_LONG_BITS == 32
/* je label1 */
tcg_out8(s, OPC_JCC_short + JCC_JE);
label1_ptr = s->code_ptr;
s->code_ptr++;
#else
/* jne label3 */
/* jne label1 */
tcg_out8(s, OPC_JCC_short + JCC_JNE);
label3_ptr = s->code_ptr;
label_ptr[0] = s->code_ptr;
s->code_ptr++;
if (TARGET_LONG_BITS == 64) {
/* cmp 4(r1), addr_reg2 */
tcg_out_modrm_offset(s, OPC_CMP_GvEv, addr_reg2, r1, 4);
/* je label1 */
tcg_out8(s, OPC_JCC_short + JCC_JE);
label1_ptr = s->code_ptr;
/* jne label1 */
tcg_out8(s, OPC_JCC_short + JCC_JNE);
label_ptr[1] = s->code_ptr;
s->code_ptr++;
}
/* TLB Hit. */
/* add x(r1), r0 */
tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
offsetof(CPUTLBEntry, addend) -
offsetof(CPUTLBEntry, addr_write));
tcg_out_qemu_st_direct(s, data_reg, data_reg2, r0, 0, opc);
/* jmp label2 */
tcg_out8(s, OPC_JMP_short);
label_ptr[2] = s->code_ptr;
s->code_ptr++;
/* label3: */
*label3_ptr = s->code_ptr - label3_ptr - 1;
#endif
/* TLB Miss. */
/* label1: */
*label_ptr[0] = s->code_ptr - label_ptr[0] - 1;
if (TARGET_LONG_BITS == 64) {
*label_ptr[1] = s->code_ptr - label_ptr[1] - 1;
}
/* XXX: move that code at the end of the TB */
#if TARGET_LONG_BITS == 32
@ -1080,23 +1083,8 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args,
tcg_out_addi(s, TCG_REG_ESP, stack_adjust);
}
/* jmp label2 */
tcg_out8(s, OPC_JMP_short);
label2_ptr = s->code_ptr;
s->code_ptr++;
/* label1: */
*label1_ptr = s->code_ptr - label1_ptr - 1;
/* add x(r1), r0 */
tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
offsetof(CPUTLBEntry, addend) -
offsetof(CPUTLBEntry, addr_write));
tcg_out_qemu_st_direct(s, data_reg, data_reg2, r0, 0, opc);
/* label2: */
*label2_ptr = s->code_ptr - label2_ptr - 1;
*label_ptr[2] = s->code_ptr - label_ptr[2] - 1;
#else
tcg_out_qemu_st_direct(s, data_reg, data_reg2, addr_reg, GUEST_BASE, opc);
#endif