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target-i386: compute eflags outside rcl/rcr helper

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Always compute EFLAGS first since it is needed whenever
the shift is non-zero, i.e. most of the time.  This makes it possible
to remove some writes of CC_OP_EFLAGS to cpu_cc_op and more importantly
removes cases where s->cc_op becomes CC_OP_DYNAMIC.  Also, we can
remove cc_tmp and just modify cc_src from within the helper.

Finally, always follow gen_compute_eflags(cpu_cc_src) by setting s->cc_op
and discarding cpu_cc_dst.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Paolo Bonzini 2012-10-06 00:18:55 +02:00 committed by Richard Henderson
parent 0ff6addd92
commit f5847c912d
3 changed files with 8 additions and 25 deletions
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1
target-i386/cpu.h
View file

@ -764,7 +764,6 @@ typedef struct CPUX86State {
XMMReg xmm_regs[CPU_NB_REGS];
XMMReg xmm_t0;
MMXReg mmx_t0;
target_ulong cc_tmp; /* temporary for rcr/rcl */
/* sysenter registers */
uint32_t sysenter_cs;

12
target-i386/shift_helper_template.h
View file

@ -55,7 +55,7 @@ target_ulong glue(helper_rcl, SUFFIX)(CPUX86State *env, target_ulong t0,
count = rclb_table[count];
#endif
if (count) {
eflags = helper_cc_compute_all(env, CC_OP);
eflags = env->cc_src;
t0 &= DATA_MASK;
src = t0;
res = (t0 << count) | ((target_ulong)(eflags & CC_C) << (count - 1));
@ -63,11 +63,9 @@ target_ulong glue(helper_rcl, SUFFIX)(CPUX86State *env, target_ulong t0,
res |= t0 >> (DATA_BITS + 1 - count);
}
t0 = res;
env->cc_tmp = (eflags & ~(CC_C | CC_O)) |
env->cc_src = (eflags & ~(CC_C | CC_O)) |
(lshift(src ^ t0, 11 - (DATA_BITS - 1)) & CC_O) |
((src >> (DATA_BITS - count)) & CC_C);
} else {
env->cc_tmp = -1;
}
return t0;
}
@ -86,7 +84,7 @@ target_ulong glue(helper_rcr, SUFFIX)(CPUX86State *env, target_ulong t0,
count = rclb_table[count];
#endif
if (count) {
eflags = helper_cc_compute_all(env, CC_OP);
eflags = env->cc_src;
t0 &= DATA_MASK;
src = t0;
res = (t0 >> count) |
@ -95,11 +93,9 @@ target_ulong glue(helper_rcr, SUFFIX)(CPUX86State *env, target_ulong t0,
res |= t0 << (DATA_BITS + 1 - count);
}
t0 = res;
env->cc_tmp = (eflags & ~(CC_C | CC_O)) |
env->cc_src = (eflags & ~(CC_C | CC_O)) |
(lshift(src ^ t0, 11 - (DATA_BITS - 1)) & CC_O) |
((src >> (count - 1)) & CC_C);
} else {
env->cc_tmp = -1;
}
return t0;
}

20
target-i386/translate.c
View file

@ -51,7 +51,7 @@
/* global register indexes */
static TCGv_ptr cpu_env;
static TCGv cpu_A0, cpu_cc_src, cpu_cc_dst, cpu_cc_tmp;
static TCGv cpu_A0, cpu_cc_src, cpu_cc_dst;
static TCGv_i32 cpu_cc_op;
static TCGv cpu_regs[CPU_NB_REGS];
/* local temps */
@ -1706,10 +1706,11 @@ static void gen_rot_rm_im(DisasContext *s, int ot, int op1, int op2,
static void gen_rotc_rm_T1(DisasContext *s, int ot, int op1,
int is_right)
{
int label1;
if (s->cc_op != CC_OP_DYNAMIC)
gen_op_set_cc_op(s->cc_op);
gen_compute_eflags(cpu_cc_src);
tcg_gen_discard_tl(cpu_cc_dst);
s->cc_op = CC_OP_EFLAGS;
/* load */
if (op1 == OR_TMP0)
@ -1757,17 +1758,6 @@ static void gen_rotc_rm_T1(DisasContext *s, int ot, int op1,
gen_op_st_T0_A0(ot + s->mem_index);
else
gen_op_mov_reg_T0(ot, op1);
/* update eflags */
label1 = gen_new_label();
tcg_gen_brcondi_tl(TCG_COND_EQ, cpu_cc_tmp, -1, label1);
tcg_gen_mov_tl(cpu_cc_src, cpu_cc_tmp);
tcg_gen_discard_tl(cpu_cc_dst);
tcg_gen_movi_i32(cpu_cc_op, CC_OP_EFLAGS);
gen_set_label(label1);
s->cc_op = CC_OP_DYNAMIC; /* cannot predict flags after */
}
/* XXX: add faster immediate case */
@ -7763,8 +7753,6 @@ void optimize_flags_init(void)
"cc_src");
cpu_cc_dst = tcg_global_mem_new(TCG_AREG0, offsetof(CPUX86State, cc_dst),
"cc_dst");
cpu_cc_tmp = tcg_global_mem_new(TCG_AREG0, offsetof(CPUX86State, cc_tmp),
"cc_tmp");
#ifdef TARGET_X86_64
cpu_regs[R_EAX] = tcg_global_mem_new_i64(TCG_AREG0,