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[Qemu-devel] [PATCH 5/8] target-arm: convert sar, shl and shr helpers to
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 5/8] target-arm: convert sar, shl and shr helpers to TCG |
Date: |
Fri, 5 Oct 2012 15:35:23 +0100 |
From: Aurelien Jarno <address@hidden>
Now that the movcond TCG op is available, it's possible to replace
shl and shr helpers by TCG code. The code generated by TCG is slightly
longer than the code generated by GCC for the helper but is still worth
it as this avoid all the consequences of using an helper: globals saved
back to memory, no possible optimization, call overhead, etc.
Signed-off-by: Aurelien Jarno <address@hidden>
Signed-off-by: Peter Maydell <address@hidden>
---
target-arm/helper.h | 3 ---
target-arm/op_helper.c | 24 ------------------------
target-arm/translate.c | 49 ++++++++++++++++++++++++++++++++++++++++++------
3 files changed, 43 insertions(+), 33 deletions(-)
diff --git a/target-arm/helper.h b/target-arm/helper.h
index 7151e28..794e2b1 100644
--- a/target-arm/helper.h
+++ b/target-arm/helper.h
@@ -145,9 +145,6 @@ DEF_HELPER_5(neon_tbl, i32, env, i32, i32, i32, i32)
DEF_HELPER_3(adc_cc, i32, env, i32, i32)
DEF_HELPER_3(sbc_cc, i32, env, i32, i32)
-DEF_HELPER_3(shl, i32, env, i32, i32)
-DEF_HELPER_3(shr, i32, env, i32, i32)
-DEF_HELPER_3(sar, i32, env, i32, i32)
DEF_HELPER_3(shl_cc, i32, env, i32, i32)
DEF_HELPER_3(shr_cc, i32, env, i32, i32)
DEF_HELPER_3(sar_cc, i32, env, i32, i32)
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index 6095f24..aef592a 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -355,30 +355,6 @@ uint32_t HELPER(sbc_cc)(CPUARMState *env, uint32_t a,
uint32_t b)
/* Similarly for variable shift instructions. */
-uint32_t HELPER(shl)(CPUARMState *env, uint32_t x, uint32_t i)
-{
- int shift = i & 0xff;
- if (shift >= 32)
- return 0;
- return x << shift;
-}
-
-uint32_t HELPER(shr)(CPUARMState *env, uint32_t x, uint32_t i)
-{
- int shift = i & 0xff;
- if (shift >= 32)
- return 0;
- return (uint32_t)x >> shift;
-}
-
-uint32_t HELPER(sar)(CPUARMState *env, uint32_t x, uint32_t i)
-{
- int shift = i & 0xff;
- if (shift >= 32)
- shift = 31;
- return (int32_t)x >> shift;
-}
-
uint32_t HELPER(shl_cc)(CPUARMState *env, uint32_t x, uint32_t i)
{
int shift = i & 0xff;
diff --git a/target-arm/translate.c b/target-arm/translate.c
index da3246a..92ceacd 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -440,6 +440,37 @@ static void gen_sub_CC(TCGv dest, TCGv t0, TCGv t1)
tcg_gen_mov_i32(dest, cpu_NF);
}
+#define GEN_SHIFT(name) \
+static void gen_##name(TCGv dest, TCGv t0, TCGv t1) \
+{ \
+ TCGv tmp1, tmp2, tmp3; \
+ tmp1 = tcg_temp_new_i32(); \
+ tcg_gen_andi_i32(tmp1, t1, 0xff); \
+ tmp2 = tcg_const_i32(0); \
+ tmp3 = tcg_const_i32(0x1f); \
+ tcg_gen_movcond_i32(TCG_COND_GTU, tmp2, tmp1, tmp3, tmp2, t0); \
+ tcg_temp_free_i32(tmp3); \
+ tcg_gen_andi_i32(tmp1, tmp1, 0x1f); \
+ tcg_gen_##name##_i32(dest, tmp2, tmp1); \
+ tcg_temp_free_i32(tmp2); \
+ tcg_temp_free_i32(tmp1); \
+}
+GEN_SHIFT(shl)
+GEN_SHIFT(shr)
+#undef GEN_SHIFT
+
+static void gen_sar(TCGv dest, TCGv t0, TCGv t1)
+{
+ TCGv tmp1, tmp2;
+ tmp1 = tcg_temp_new_i32();
+ tcg_gen_andi_i32(tmp1, t1, 0xff);
+ tmp2 = tcg_const_i32(0x1f);
+ tcg_gen_movcond_i32(TCG_COND_GTU, tmp1, tmp1, tmp2, tmp2, tmp1);
+ tcg_temp_free_i32(tmp2);
+ tcg_gen_sar_i32(dest, t0, tmp1);
+ tcg_temp_free_i32(tmp1);
+}
+
/* FIXME: Implement this natively. */
#define tcg_gen_abs_i32(t0, t1) gen_helper_abs(t0, t1)
@@ -516,9 +547,15 @@ static inline void gen_arm_shift_reg(TCGv var, int shiftop,
}
} else {
switch (shiftop) {
- case 0: gen_helper_shl(var, cpu_env, var, shift); break;
- case 1: gen_helper_shr(var, cpu_env, var, shift); break;
- case 2: gen_helper_sar(var, cpu_env, var, shift); break;
+ case 0:
+ gen_shl(var, var, shift);
+ break;
+ case 1:
+ gen_shr(var, var, shift);
+ break;
+ case 2:
+ gen_sar(var, var, shift);
+ break;
case 3: tcg_gen_andi_i32(shift, shift, 0x1f);
tcg_gen_rotr_i32(var, var, shift); break;
}
@@ -9161,7 +9198,7 @@ static void disas_thumb_insn(CPUARMState *env,
DisasContext *s)
break;
case 0x2: /* lsl */
if (s->condexec_mask) {
- gen_helper_shl(tmp2, cpu_env, tmp2, tmp);
+ gen_shl(tmp2, tmp2, tmp);
} else {
gen_helper_shl_cc(tmp2, cpu_env, tmp2, tmp);
gen_logic_CC(tmp2);
@@ -9169,7 +9206,7 @@ static void disas_thumb_insn(CPUARMState *env,
DisasContext *s)
break;
case 0x3: /* lsr */
if (s->condexec_mask) {
- gen_helper_shr(tmp2, cpu_env, tmp2, tmp);
+ gen_shr(tmp2, tmp2, tmp);
} else {
gen_helper_shr_cc(tmp2, cpu_env, tmp2, tmp);
gen_logic_CC(tmp2);
@@ -9177,7 +9214,7 @@ static void disas_thumb_insn(CPUARMState *env,
DisasContext *s)
break;
case 0x4: /* asr */
if (s->condexec_mask) {
- gen_helper_sar(tmp2, cpu_env, tmp2, tmp);
+ gen_sar(tmp2, tmp2, tmp);
} else {
gen_helper_sar_cc(tmp2, cpu_env, tmp2, tmp);
gen_logic_CC(tmp2);
--
1.7.9.5
- [Qemu-devel] [PULL 0/8] target-arm queue, Peter Maydell, 2012/10/05
- [Qemu-devel] [PATCH 7/8] target-arm: use deposit instead of hardcoded version, Peter Maydell, 2012/10/05
- [Qemu-devel] [PATCH 4/8] target-arm: convert add_cc and sub_cc helpers to TCG, Peter Maydell, 2012/10/05
- [Qemu-devel] [PATCH 6/8] target-arm: mark a few integer helpers const and pure, Peter Maydell, 2012/10/05
- [Qemu-devel] [PATCH 8/8] target-arm: Drop unused DECODE_CPREG_CRN macro, Peter Maydell, 2012/10/05
- [Qemu-devel] [PATCH 2/8] target-arm: Reinstate display of VFP registers in cpu_dump_state, Peter Maydell, 2012/10/05
- [Qemu-devel] [PATCH 5/8] target-arm: convert sar, shl and shr helpers to TCG,
Peter Maydell <=
- [Qemu-devel] [PATCH 3/8] target-arm: use globals for CC flags, Peter Maydell, 2012/10/05
- [Qemu-devel] [PATCH 1/8] cpu_dump_state: move DUMP_FPU and DUMP_CCOP flags from x86-only to generic, Peter Maydell, 2012/10/05
- Re: [Qemu-devel] [PULL 0/8] target-arm queue, Aurelien Jarno, 2012/10/06