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Re: [Qemu-devel] [Qemu-arm] [PATCH 9/9] target/arm: Simplify BFXIL expan
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [Qemu-devel] [Qemu-arm] [PATCH 9/9] target/arm: Simplify BFXIL expansion |
Date: |
Sat, 9 Mar 2019 01:45:34 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 |
On 3/7/19 3:41 PM, Richard Henderson wrote:
> The mask implied by the extract is redundant with the one
> implied by the deposit. Also, fix spelling of BFXIL.
This spelling fix also help understanding the context!
>
> Cc: address@hidden
> Cc: Peter Maydell <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> target/arm/translate-a64.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
> index 54fe94c436..39e0512d21 100644
> --- a/target/arm/translate-a64.c
> +++ b/target/arm/translate-a64.c
> @@ -4043,8 +4043,8 @@ static void disas_bitfield(DisasContext *s, uint32_t
> insn)
> tcg_gen_extract_i64(tcg_rd, tcg_tmp, ri, len);
> return;
> }
> - /* opc == 1, BXFIL fall through to deposit */
> - tcg_gen_extract_i64(tcg_tmp, tcg_tmp, ri, len);
> + /* opc == 1, BFXIL fall through to deposit */
> + tcg_gen_shri_i64(tcg_tmp, tcg_tmp, ri);
> pos = 0;
> } else {
> /* Handle the ri > si case with a deposit
> @@ -4062,7 +4062,7 @@ static void disas_bitfield(DisasContext *s, uint32_t
> insn)
> len = ri;
> }
>
> - if (opc == 1) { /* BFM, BXFIL */
> + if (opc == 1) { /* BFM, BFXIL */
> tcg_gen_deposit_i64(tcg_rd, tcg_rd, tcg_tmp, pos, len);
Fall through and use deposit of len indeed. So the previous SHRI is enough.
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
This function uses hardcore optimizations btw, un chef d'oeuvre :)
> } else {
> /* SBFM or UBFM: We start with zero, and we haven't modified
>
- Re: [Qemu-devel] [PATCH 2/9] tcg: Add INDEX_op_extract2_{i32,i64}, (continued)
- [Qemu-devel] [PATCH 5/9] tcg/i386: Support INDEX_op_extract2_{i32, i64}, Richard Henderson, 2019/03/07
- [Qemu-devel] [PATCH 6/9] tcg/arm: Support INDEX_op_extract2_i32, Richard Henderson, 2019/03/07
- [Qemu-devel] [PATCH 7/9] tcg/aarch64: Support INDEX_op_extract2_{i32, i64}, Richard Henderson, 2019/03/07
- [Qemu-devel] [PATCH 9/9] target/arm: Simplify BFXIL expansion, Richard Henderson, 2019/03/07
- Re: [Qemu-devel] [Qemu-arm] [PATCH 9/9] target/arm: Simplify BFXIL expansion,
Philippe Mathieu-Daudé <=
- [Qemu-devel] [PATCH 8/9] target/arm: Use extract2 for EXTR, Richard Henderson, 2019/03/07
- Re: [Qemu-devel] [PATCH 0/9] tcg: Add tcg_gen_extract2_{i32,i64}, no-reply, 2019/03/07
- Re: [Qemu-devel] [PATCH 0/9] tcg: Add tcg_gen_extract2_{i32,i64}, no-reply, 2019/03/07
- Re: [Qemu-devel] [PATCH 0/9] tcg: Add tcg_gen_extract2_{i32,i64}, no-reply, 2019/03/08
- Re: [Qemu-devel] [PATCH 0/9] tcg: Add tcg_gen_extract2_{i32,i64}, no-reply, 2019/03/08
- Re: [Qemu-devel] [PATCH 0/9] tcg: Add tcg_gen_extract2_{i32,i64}, no-reply, 2019/03/08
- Re: [Qemu-devel] [PATCH 0/9] tcg: Add tcg_gen_extract2_{i32,i64}, no-reply, 2019/03/08