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Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing
From: |
Richard Henderson |
Subject: |
Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing |
Date: |
Tue, 21 Jan 2020 22:53:27 -1000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 |
On 1/21/20 9:24 PM, Ian Jiang wrote:
> For FMV.W.X that moves the lower 32 bits of an integer register to a
> floating-point register, Rd should encoded with NoN-boxing scheme.
> Note: This applies to RV64 only.
>
> Signed-off-by: Ian Jiang <address@hidden>
> ---
> target/riscv/insn_trans/trans_rvf.inc.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/target/riscv/insn_trans/trans_rvf.inc.c
> b/target/riscv/insn_trans/trans_rvf.inc.c
> index 172dbfa919..62b7a36567 100644
> --- a/target/riscv/insn_trans/trans_rvf.inc.c
> +++ b/target/riscv/insn_trans/trans_rvf.inc.c
> @@ -368,6 +368,7 @@ static bool trans_fmv_w_x(DisasContext *ctx, arg_fmv_w_x
> *a)
>
> #if defined(TARGET_RISCV64)
> tcg_gen_mov_i64(cpu_fpr[a->rd], t0);
> + tcg_gen_ori_i64(cpu_fpr[a->rd], cpu_fpr[a->rd], 0xffffffff00000000ULL);
> #else
> tcg_gen_extu_i32_i64(cpu_fpr[a->rd], t0);
> #endif
>
This doesn't look right. There's nothing in the spec that says the nan-boxing
is restricted to rv64. NaN-boxing is all about FLEN, not XLEN.
r~
- [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Ian Jiang, 2020/01/22
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing,
Richard Henderson <=
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Ian Jiang, 2020/01/22
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Richard Henderson, 2020/01/22
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Ian Jiang, 2020/01/22
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Richard Henderson, 2020/01/22
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Ian Jiang, 2020/01/22
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Richard Henderson, 2020/01/23
- Re: [PATCH] riscv: Format Rd of FMV.W.X with NoN-boxing, Ian Jiang, 2020/01/27