On Sat, Oct 6, 2012 at 12:30 PM, Paolo Bonzini <pbonz...@redhat.com> wrote:
> ZF, SF and PF can always be computed from CC_DST except in the
> CC_OP_EFLAGS case (and CC_OP_DYNAMIC, which just resolves to CC_OP_EFLAGS
> in gen_compute_eflags). Use setcond to compute ZF and SF.
>
> We could also use a table lookup to compute PF.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Blue Swirl <blauwir...@gmail.com>
> ---
> target-i386/translate.c | 28 ++++++++++++++++++++++------
> 1 file modificato, 22 inserzioni(+), 6 rimozioni(-)
>
> diff --git a/target-i386/translate.c b/target-i386/translate.c
> index 09512c3..daa36c1 100644
> --- a/target-i386/translate.c
> +++ b/target-i386/translate.c
> @@ -859,9 +859,17 @@ static void gen_compute_eflags_p(DisasContext *s, TCGv
> reg)
> /* compute eflags.S to reg */
> static void gen_compute_eflags_s(DisasContext *s, TCGv reg)
> {
> - gen_compute_eflags(s);
> - tcg_gen_shri_tl(reg, cpu_cc_src, 7);
> - tcg_gen_andi_tl(reg, reg, 1);
> + if (s->cc_op == CC_OP_DYNAMIC) {
> + gen_compute_eflags(s);
> + }
> + if (s->cc_op == CC_OP_EFLAGS) {
> + tcg_gen_shri_tl(reg, cpu_cc_src, 7);
> + tcg_gen_andi_tl(reg, reg, 1);
> + } else {
A comment would be nice here, like something extracted from commit message.
> + int size = (s->cc_op - CC_OP_ADDB) & 3;
> + gen_ext_tl(reg, cpu_cc_dst, size, true);
> + tcg_gen_setcondi_tl(TCG_COND_LT, reg, reg, 0);
> + }
> }
>
> /* compute eflags.O to reg */
> @@ -875,9 +883,17 @@ static void gen_compute_eflags_o(DisasContext *s, TCGv
> reg)
> /* compute eflags.Z to reg */
> static void gen_compute_eflags_z(DisasContext *s, TCGv reg)
> {
> - gen_compute_eflags(s);
> - tcg_gen_shri_tl(reg, cpu_cc_src, 6);
> - tcg_gen_andi_tl(reg, reg, 1);
> + if (s->cc_op == CC_OP_DYNAMIC) {
> + gen_compute_eflags(s);
> + }
> + if (s->cc_op == CC_OP_EFLAGS) {
> + tcg_gen_shri_tl(reg, cpu_cc_src, 6);
> + tcg_gen_andi_tl(reg, reg, 1);
> + } else {
Ditto.
> + int size = (s->cc_op - CC_OP_ADDB) & 3;
> + gen_ext_tl(reg, cpu_cc_dst, size, false);
> + tcg_gen_setcondi_tl(TCG_COND_EQ, reg, cpu_cc_dst, 0);
> + }
> }
>
> static inline void gen_setcc_slow_T0(DisasContext *s, int jcc_op)
> --
> 1.7.12.1
>
>
>
