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From: Paolo Bonzini <pbonzini@redhat.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: qemu-devel@nongnu.org
Subject: Re: [PATCH v2 18/23] target/i386: Use gen_jmp_rel for loop and jecxz insns
Date: Wed, 21 Sep 2022 15:06:45 +0200	[thread overview]
Message-ID: <CABgObfahdNGb2EGBffKnNp-5J0OAiMyToyp3SqqvDGgQy-kmRQ@mail.gmail.com> (raw)
In-Reply-To: <20220906100932.343523-19-richard.henderson@linaro.org>

On Tue, Sep 6, 2022 at 12:09 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> With gen_jmp_rel, we may chain to the next tb
> instead of merely writing to eip and exiting.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

See comment on the previous patch.

Paolo

> ---
>  target/i386/tcg/translate.c | 21 ++++++---------------
>  1 file changed, 6 insertions(+), 15 deletions(-)
>
> diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
> index 07c7764649..fdd17c3cf3 100644
> --- a/target/i386/tcg/translate.c
> +++ b/target/i386/tcg/translate.c
> @@ -7355,24 +7355,18 @@ static bool disas_insn(DisasContext *s, CPUState *cpu)
>      case 0xe2: /* loop */
>      case 0xe3: /* jecxz */
>          {
> -            TCGLabel *l1, *l2, *l3;
> -
> -            tval = (int8_t)insn_get(env, s, MO_8);
> -            tval += s->pc - s->cs_base;
> -            if (dflag == MO_16) {
> -                tval &= 0xffff;
> -            }
> +            TCGLabel *l1, *l2;
> +            int diff = (int8_t)insn_get(env, s, MO_8);
>
>              l1 = gen_new_label();
>              l2 = gen_new_label();
> -            l3 = gen_new_label();
>              gen_update_cc_op(s);
>              b &= 3;
>              switch(b) {
>              case 0: /* loopnz */
>              case 1: /* loopz */
>                  gen_op_add_reg_im(s, s->aflag, R_ECX, -1);
> -                gen_op_jz_ecx(s, s->aflag, l3);
> +                gen_op_jz_ecx(s, s->aflag, l2);
>                  gen_jcc1(s, (JCC_Z << 1) | (b ^ 1), l1);
>                  break;
>              case 2: /* loop */
> @@ -7385,14 +7379,11 @@ static bool disas_insn(DisasContext *s, CPUState *cpu)
>                  break;
>              }
>
> -            gen_set_label(l3);
> -            gen_update_eip_next(s);
> -            tcg_gen_br(l2);
> +            gen_set_label(l2);
> +            gen_jmp_rel(s, MO_32, 0, 1);
>
>              gen_set_label(l1);
> -            gen_jmp_im(s, tval);
> -            gen_set_label(l2);
> -            s->base.is_jmp = DISAS_EOB_ONLY;
> +            gen_jmp_rel(s, dflag, diff, 0);
>          }
>          break;
>      case 0x130: /* wrmsr */
> --
> 2.34.1
>



  reply	other threads:[~2022-09-21 13:56 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-06 10:09 [PATCH v2 00/23] target/i386: pc-relative translation blocks Richard Henderson
2022-09-06 10:09 ` [PATCH v2 01/23] target/i386: Remove pc_start Richard Henderson
2022-09-21 11:49   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 02/23] target/i386: Return bool from disas_insn Richard Henderson
2022-09-06 14:42   ` Philippe Mathieu-Daudé via
2022-09-08 12:14     ` Richard Henderson
2022-09-21 17:51       ` Philippe Mathieu-Daudé via
2022-09-06 10:09 ` [PATCH v2 03/23] target/i386: Remove cur_eip argument to gen_exception Richard Henderson
2022-09-06 14:44   ` Philippe Mathieu-Daudé via
2022-09-21 11:51     ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 04/23] target/i386: Remove cur_eip, next_eip arguments to gen_interrupt Richard Henderson
2022-09-06 14:46   ` Philippe Mathieu-Daudé via
2022-09-21 11:51     ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 05/23] target/i386: Create gen_update_eip_cur Richard Henderson
2022-09-21 11:58   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 06/23] target/i386: Create gen_update_eip_next Richard Henderson
2022-09-21 12:04   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 07/23] target/i386: Introduce DISAS_EOB* Richard Henderson
2022-09-21 12:05   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 08/23] target/i386: Use DISAS_EOB* in gen_movl_seg_T0 Richard Henderson
2022-09-21 12:09   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 09/23] target/i386: Use DISAS_EOB_NEXT Richard Henderson
2022-09-21 12:25   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 10/23] target/i386: USe DISAS_EOB_ONLY Richard Henderson
2022-09-21 12:10   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 11/23] target/i386: Create cur_insn_len, cur_insn_len_i32 Richard Henderson
2022-09-06 14:49   ` Philippe Mathieu-Daudé via
2022-09-21 12:25     ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 12/23] target/i386: Remove cur_eip, next_eip arguments to gen_repz* Richard Henderson
2022-09-21 12:26   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 13/23] target/i386: Introduce DISAS_JUMP Richard Henderson
2022-09-21 12:28   ` Paolo Bonzini
2022-09-21 23:27     ` Richard Henderson
2022-09-06 10:09 ` [PATCH v2 14/23] target/i386: Truncate values for lcall_real to i32 Richard Henderson
2022-09-21 12:29   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 15/23] target/i386: Create eip_next_* Richard Henderson
2022-09-21 12:34   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 16/23] target/i386: Use DISAS_TOO_MANY to exit after gen_io_start Richard Henderson
2022-09-21 12:38   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 17/23] target/i386: Create gen_jmp_rel Richard Henderson
2022-09-21 13:06   ` Paolo Bonzini
2022-10-01  0:53     ` Richard Henderson
2022-10-01  6:54       ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 18/23] target/i386: Use gen_jmp_rel for loop and jecxz insns Richard Henderson
2022-09-21 13:06   ` Paolo Bonzini [this message]
2022-09-06 10:09 ` [PATCH v2 19/23] target/i386: Use gen_jmp_rel for gen_jcc Richard Henderson
2022-09-21 13:09   ` Paolo Bonzini
2022-10-01  1:04     ` Richard Henderson
2022-10-01  7:03       ` Paolo Bonzini
2022-10-01 13:58         ` Richard Henderson
2022-09-06 10:09 ` [PATCH v2 20/23] target/i386: Use gen_jmp_rel for gen_repz* Richard Henderson
2022-09-21 13:10   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 21/23] target/i386: Use gen_jmp_rel for DISAS_TOO_MANY Richard Henderson
2022-09-21 13:11   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 22/23] target/i386: Create gen_eip_cur Richard Henderson
2022-09-06 14:50   ` Philippe Mathieu-Daudé via
2022-09-21 13:12   ` Paolo Bonzini
2022-09-06 10:09 ` [PATCH v2 23/23] target/i386: Enable TARGET_TB_PCREL Richard Henderson
2022-09-21 13:31   ` Paolo Bonzini
2022-10-01  1:51     ` Richard Henderson
2022-09-21 13:32 ` [PATCH v2 00/23] target/i386: pc-relative translation blocks Paolo Bonzini

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