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target-arm: convert sar, shl and shr helpers to TCG 

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 <aurelien@aurel32.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Aurelien Jarno 2012-10-05 15:04:44 +01:00 committed by Peter Maydell
parent 72485ec4f6
commit 365af80e47
3 changed files with 43 additions and 33 deletions
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3
target-arm/helper.h
View File

@ -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)

24
target-arm/op_helper.c
View File

@ -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;

49
target-arm/translate.c
View File

@ -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);