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[Qemu-devel] [PATCH 56/57] target-i386: Simplify bsf/bsr flags computati
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 56/57] target-i386: Simplify bsf/bsr flags computation |
Date: |
Wed, 23 Jan 2013 20:03:40 -0800 |
There's no need for a branch or for a local temporary.
Signed-off-by: Richard Henderson <address@hidden>
---
target-i386/translate.c | 60 +++++++++++++++++++++----------------------------
1 file changed, 25 insertions(+), 35 deletions(-)
diff --git a/target-i386/translate.c b/target-i386/translate.c
index fdb06a1..a9bc21d 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -7153,44 +7153,34 @@ static target_ulong disas_insn(CPUX86State *env,
DisasContext *s,
break;
case 0x1bc: /* bsf */
case 0x1bd: /* bsr */
- {
- int label1;
- TCGv t0;
-
- ot = dflag + OT_WORD;
- modrm = cpu_ldub_code(env, s->pc++);
- reg = ((modrm >> 3) & 7) | rex_r;
- gen_ldst_modrm(env, s,modrm, ot, OR_TMP0, 0);
- gen_extu(ot, cpu_T[0]);
- t0 = tcg_temp_local_new();
- tcg_gen_mov_tl(t0, cpu_T[0]);
- if ((b & 1) && (prefixes & PREFIX_REPZ) &&
- (s->cpuid_ext3_features & CPUID_EXT3_ABM)) {
- switch(ot) {
- case OT_WORD: gen_helper_lzcnt(cpu_T[0], t0,
- tcg_const_i32(16)); break;
- case OT_LONG: gen_helper_lzcnt(cpu_T[0], t0,
- tcg_const_i32(32)); break;
- case OT_QUAD: gen_helper_lzcnt(cpu_T[0], t0,
- tcg_const_i32(64)); break;
- }
- gen_op_mov_reg_T0(ot, reg);
+ ot = dflag + OT_WORD;
+ modrm = cpu_ldub_code(env, s->pc++);
+ reg = ((modrm >> 3) & 7) | rex_r;
+ gen_ldst_modrm(env, s, modrm, ot, OR_TMP0, 0);
+ gen_extu(ot, cpu_T[0]);
+ if ((b & 1) && (prefixes & PREFIX_REPZ) &&
+ (s->cpuid_ext3_features & CPUID_EXT3_ABM)) {
+ switch (ot) {
+ case OT_WORD:
+ gen_helper_lzcnt(cpu_T[0], cpu_T[0], tcg_const_i32(16));
+ break;
+ case OT_LONG:
+ gen_helper_lzcnt(cpu_T[0], cpu_T[0], tcg_const_i32(32));
+ break;
+ case OT_QUAD:
+ gen_helper_lzcnt(cpu_T[0], cpu_T[0], tcg_const_i32(64));
+ break;
+ }
+ } else {
+ tcg_gen_mov_tl(cpu_cc_dst, cpu_T[0]);
+ set_cc_op(s, CC_OP_LOGICB + ot);
+ if (b & 1) {
+ gen_helper_bsr(cpu_T[0], cpu_T[0]);
} else {
- label1 = gen_new_label();
- tcg_gen_movi_tl(cpu_cc_dst, 0);
- tcg_gen_brcondi_tl(TCG_COND_EQ, t0, 0, label1);
- if (b & 1) {
- gen_helper_bsr(cpu_T[0], t0);
- } else {
- gen_helper_bsf(cpu_T[0], t0);
- }
- gen_op_mov_reg_T0(ot, reg);
- tcg_gen_movi_tl(cpu_cc_dst, 1);
- gen_set_label(label1);
- set_cc_op(s, CC_OP_LOGICB + ot);
+ gen_helper_bsf(cpu_T[0], cpu_T[0]);
}
- tcg_temp_free(t0);
}
+ gen_op_mov_reg_T0(ot, reg);
break;
/************************/
/* bcd */
--
1.7.11.7
- [Qemu-devel] [PATCH 16/57] target-i386: Use gen_update_cc_op everywhere, (continued)
- [Qemu-devel] [PATCH 16/57] target-i386: Use gen_update_cc_op everywhere, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 25/57] target-i386: optimize setbe, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 23/57] target-i386: convert gen_compute_eflags_c to TCG, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 28/57] target-i386: introduce CCPrepare, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 30/57] target-i386: use CCPrepare to generate conditional jumps, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 43/57] target-i386: Tidy prefix parsing, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 42/57] target-i386: Make helper_cc_compute_all const, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 53/57] target-i386: Implement RORX, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 55/57] target-i386: Use clz/ctz for bsf/bsr helpers, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 54/57] target-i386: Implement ADX extension, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 56/57] target-i386: Simplify bsf/bsr flags computation,
Richard Henderson <=
- [Qemu-devel] [PATCH 57/57] target-i386: Implement tzcnt and fix lzcnt, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 33/57] target-i386: introduce gen_cmovcc1, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 31/57] target-i386: inline gen_prepare_cc_slow, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 40/57] target-i386: Use CC_SRC2 for ADC and SBB, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 35/57] target-i386: kill cpu_T3, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 49/57] target-i386: Implement BZHI, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 39/57] target-i386: optimize flags checking after sub using CC_SRC2, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 36/57] target-i386: use gen_op for cmps/scas, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 48/57] target-i386: Implement BLSR, BLSMSK, BLSI, Richard Henderson, 2013/01/23
- [Qemu-devel] [PATCH 46/57] target-i386: Implement ANDN, Richard Henderson, 2013/01/23