Re: [Qemu-devel] [PATCH 10/67] target/arm: Move test for AL into arm_skip_unless

[Peter Maydell]

On Fri, 26 Jul 2019 at 18:50, Richard Henderson
<address@hidden> wrote:
>
> We will shortly be calling this function much more often.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  target/arm/translate.c | 28 ++++++++++++----------------
>  1 file changed, 12 insertions(+), 16 deletions(-)
>
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 53c46fcdc4..36419025db 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -7705,8 +7705,14 @@ static void arm_gen_condlabel(DisasContext *s)
>  /* Skip this instruction if the ARM condition is false */
>  static void arm_skip_unless(DisasContext *s, uint32_t cond)
>  {
> -    arm_gen_condlabel(s);
> -    arm_gen_test_cc(cond ^ 1, s->condlabel);
> +    /*
> +     * Conditionally skip the insn. Note that both 0xe and 0xf mean
> +     * "always"; 0xf is not "never".
> +     */
> +    if (cond < 0xe) {
> +        arm_gen_condlabel(s);
> +        arm_gen_test_cc(cond ^ 1, s->condlabel);
> +    }
>  }
>
>  static void disas_arm_insn(DisasContext *s, unsigned int insn)
> @@ -7944,11 +7950,9 @@ static void disas_arm_insn(DisasContext *s, unsigned 
> int insn)
>          }
>          goto illegal_op;
>      }
> -    if (cond != 0xe) {
> -        /* if not always execute, we generate a conditional jump to
> -           next instruction */
> -        arm_skip_unless(s, cond);
> -    }
> +
> +    arm_skip_unless(s, cond);
> +
>      if ((insn & 0x0f900000) == 0x03000000) {
>          if ((insn & (1 << 21)) == 0) {
>              ARCH(6T2);
> @@ -12095,15 +12099,7 @@ static void thumb_tr_translate_insn(DisasContextBase 
> *dcbase, CPUState *cpu)
>      dc->insn = insn;
>
>      if (dc->condexec_mask && !thumb_insn_is_unconditional(dc, insn)) {
> -        uint32_t cond = dc->condexec_cond;
> -
> -        /*
> -         * Conditionally skip the insn. Note that both 0xe and 0xf mean
> -         * "always"; 0xf is not "never".
> -         */
> -        if (cond < 0x0e) {
> -            arm_skip_unless(dc, cond);
> -        }
> +        arm_skip_unless(dc, dc->condexec_cond);
>      }

In the other callsites for arm_skip_unless() the cond argument
can never be 0xe or 0xf.

Reviewed-by: Peter Maydell <address@hidden>

thanks
-- PMM