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Diffstat (limited to 'target-i386/translate.c')
-rw-r--r--target-i386/translate.c31
1 files changed, 27 insertions, 4 deletions
diff --git a/target-i386/translate.c b/target-i386/translate.c
index 31e3442442..5235aff15e 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -882,13 +882,37 @@ static void gen_op_update_neg_cc(void)
/* compute all eflags to cc_src */
static void gen_compute_eflags(DisasContext *s)
{
+ TCGv zero, dst, src1;
+ int live, dead;
+
if (s->cc_op == CC_OP_EFLAGS) {
return;
}
+
+ TCGV_UNUSED(zero);
+ dst = cpu_cc_dst;
+ src1 = cpu_cc_src;
+
+ /* Take care to not read values that are not live. */
+ live = cc_op_live[s->cc_op] & ~USES_CC_SRCT;
+ dead = live ^ (USES_CC_DST | USES_CC_SRC);
+ if (dead) {
+ zero = tcg_const_tl(0);
+ if (dead & USES_CC_DST) {
+ dst = zero;
+ }
+ if (dead & USES_CC_SRC) {
+ src1 = zero;
+ }
+ }
+
gen_update_cc_op(s);
- gen_helper_cc_compute_all(cpu_tmp2_i32, cpu_env, cpu_cc_op);
+ gen_helper_cc_compute_all(cpu_cc_src, dst, src1, cpu_cc_op);
set_cc_op(s, CC_OP_EFLAGS);
- tcg_gen_extu_i32_tl(cpu_cc_src, cpu_tmp2_i32);
+
+ if (dead) {
+ tcg_temp_free(zero);
+ }
}
typedef struct CCPrepare {
@@ -980,8 +1004,7 @@ static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
/* The need to compute only C from CC_OP_DYNAMIC is important
in efficiently implementing e.g. INC at the start of a TB. */
gen_update_cc_op(s);
- gen_helper_cc_compute_c(cpu_tmp2_i32, cpu_env, cpu_cc_op);
- tcg_gen_extu_i32_tl(reg, cpu_tmp2_i32);
+ gen_helper_cc_compute_c(reg, cpu_cc_dst, cpu_cc_src, cpu_cc_op);
return (CCPrepare) { .cond = TCG_COND_NE, .reg = reg,
.mask = -1, .no_setcond = true };
}