From 0ff6addd92979b9759efa1c0945526e6ac78ce5b Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Sat, 6 Oct 2012 00:18:55 +0200 Subject: target-i386: move eflags computation closer to gen_op_set_cc_op This ensures the invariant that cpu_cc_op matches s->cc_op when calling the helpers. The next patches need this because gen_compute_eflags and gen_compute_eflags_c will take care of setting cpu_cc_op. 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. These are slow and we want to avoid them: CC_OP_EFLAGS is quite efficient once we paid the initial cost of computing the flags. Finally, always follow gen_compute_eflags(cpu_cc_src) by setting s->cc_op and discarding cpu_cc_dst. Signed-off-by: Paolo Bonzini Signed-off-by: Richard Henderson --- target-i386/translate.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'target-i386/translate.c') diff --git a/target-i386/translate.c b/target-i386/translate.c index ed373c3..0970954 100644 --- a/target-i386/translate.c +++ b/target-i386/translate.c @@ -1597,14 +1597,16 @@ static void gen_rot_rm_T1(DisasContext *s, int ot, int op1, gen_op_mov_reg_v(ot, op1, t0); } - /* update eflags */ + /* update eflags. It is needed anyway most of the time, do it always. */ 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; label2 = gen_new_label(); tcg_gen_brcondi_tl(TCG_COND_EQ, t1, 0, label2); - gen_compute_eflags(cpu_cc_src); tcg_gen_andi_tl(cpu_cc_src, cpu_cc_src, ~(CC_O | CC_C)); tcg_gen_xor_tl(cpu_tmp0, t2, t0); tcg_gen_lshift(cpu_tmp0, cpu_tmp0, 11 - (data_bits - 1)); @@ -1615,12 +1617,8 @@ static void gen_rot_rm_T1(DisasContext *s, int ot, int op1, } tcg_gen_andi_tl(t0, t0, CC_C); tcg_gen_or_tl(cpu_cc_src, cpu_cc_src, t0); - - tcg_gen_discard_tl(cpu_cc_dst); - tcg_gen_movi_i32(cpu_cc_op, CC_OP_EFLAGS); - + gen_set_label(label2); - s->cc_op = CC_OP_DYNAMIC; /* cannot predict flags after */ tcg_temp_free(t0); tcg_temp_free(t1); @@ -1684,6 +1682,9 @@ static void gen_rot_rm_im(DisasContext *s, int ot, int op1, int op2, 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; + tcg_gen_andi_tl(cpu_cc_src, cpu_cc_src, ~(CC_O | CC_C)); tcg_gen_xor_tl(cpu_tmp0, t1, t0); tcg_gen_lshift(cpu_tmp0, cpu_tmp0, 11 - (data_bits - 1)); @@ -1694,10 +1695,6 @@ static void gen_rot_rm_im(DisasContext *s, int ot, int op1, int op2, } tcg_gen_andi_tl(t0, t0, CC_C); tcg_gen_or_tl(cpu_cc_src, cpu_cc_src, t0); - - tcg_gen_discard_tl(cpu_cc_dst); - tcg_gen_movi_i32(cpu_cc_op, CC_OP_EFLAGS); - s->cc_op = CC_OP_EFLAGS; } tcg_temp_free(t0); -- cgit v1.1