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authorRichard Henderson <rth@twiddle.net>2013-01-23 16:10:49 -0800
committerRichard Henderson <rth@twiddle.net>2013-02-18 15:25:55 -0800
commitdb9f2597722d5d8bc5f2330f186288d893114338 (patch)
tree240c865992c49a148ba7df2e0d50dffa7cb04a88
parent8601c0b6c553a018fc62007efa8ac2a71d77f449 (diff)
target-i386: Make helper_cc_compute_{all,c} const
Pass the data in explicitly, rather than indirectly via env. This avoids all sorts of unnecessary register spillage. Signed-off-by: Richard Henderson <rth@twiddle.net>
-rw-r--r--target-i386/cc_helper.c12
-rw-r--r--target-i386/helper.h4
-rw-r--r--target-i386/translate.c31
3 files changed, 33 insertions, 14 deletions
diff --git a/target-i386/cc_helper.c b/target-i386/cc_helper.c
index 61427ddeac..a5d8181804 100644
--- a/target-i386/cc_helper.c
+++ b/target-i386/cc_helper.c
@@ -75,10 +75,8 @@ const uint8_t parity_table[256] = {
#endif
-uint32_t helper_cc_compute_all(CPUX86State *env, int op)
+target_ulong helper_cc_compute_all(target_ulong dst, target_ulong src1, int op)
{
- target_ulong dst = CC_DST, src1 = CC_SRC;
-
switch (op) {
default: /* should never happen */
return 0;
@@ -183,13 +181,11 @@ uint32_t helper_cc_compute_all(CPUX86State *env, int op)
uint32_t cpu_cc_compute_all(CPUX86State *env, int op)
{
- return helper_cc_compute_all(env, op);
+ return helper_cc_compute_all(CC_DST, CC_SRC, op);
}
-uint32_t helper_cc_compute_c(CPUX86State *env, int op)
+target_ulong helper_cc_compute_c(target_ulong dst, target_ulong src1, int op)
{
- target_ulong dst = CC_DST, src1 = CC_SRC;
-
switch (op) {
default: /* should never happen */
case CC_OP_LOGICB:
@@ -281,7 +277,7 @@ target_ulong helper_read_eflags(CPUX86State *env)
{
uint32_t eflags;
- eflags = helper_cc_compute_all(env, CC_OP);
+ eflags = cpu_cc_compute_all(env, CC_OP);
eflags |= (DF & DF_MASK);
eflags |= env->eflags & ~(VM_MASK | RF_MASK);
return eflags;
diff --git a/target-i386/helper.h b/target-i386/helper.h
index 9ed720d0ed..901ff73c12 100644
--- a/target-i386/helper.h
+++ b/target-i386/helper.h
@@ -1,7 +1,7 @@
#include "exec/def-helper.h"
-DEF_HELPER_FLAGS_2(cc_compute_all, TCG_CALL_NO_SE, i32, env, int)
-DEF_HELPER_FLAGS_2(cc_compute_c, TCG_CALL_NO_SE, i32, env, int)
+DEF_HELPER_FLAGS_3(cc_compute_all, TCG_CALL_NO_RWG_SE, tl, tl, tl, int)
+DEF_HELPER_FLAGS_3(cc_compute_c, TCG_CALL_NO_RWG_SE, tl, tl, tl, int)
DEF_HELPER_0(lock, void)
DEF_HELPER_0(unlock, void)
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 };
}