Re: [RFC v2 21/76] target/riscv: rvv-0.9: configure instructions

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Re: [RFC v2 21/76] target/riscv: rvv-0.9: configure instructions

From:	Richard Henderson
Subject:	Re: [RFC v2 21/76] target/riscv: rvv-0.9: configure instructions
Date:	Wed, 22 Jul 2020 13:00:21 -0700
User-agent:	Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0

On 7/22/20 2:15 AM, frank.chang@sifive.com wrote:
> +    float vflmul = flmul_table[lmul];
> +
> +    if ((sew > cpu->cfg.elen)
> +        || vill
> +        || vflmul < ((float)sew / cpu->cfg.elen)

Hmm.  I suppose this is fairly compact.

Expanding this to integer code would take something like

    if (vflmul & 4) {
        /* Fractional LMUL. */
        if (vflmul == 4 ||
            cpu->cfg.elen >> (8 - vflmul) < sew) {
            vill = 1;
        }
    }


r~

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Re: [RFC v2 16/76] target/riscv: rvv-0.9: add VMA and VTA, (continued)
- [RFC v2 17/76] target/riscv: rvv-0.9: update check functions, frank . chang, 2020/07/22
- [RFC v2 18/76] target/riscv: introduce more imm value modes in translator functions, frank . chang, 2020/07/22
  - Re: [RFC v2 18/76] target/riscv: introduce more imm value modes in translator functions, Richard Henderson, 2020/07/22
- [RFC v2 19/76] target/riscv: rvv-0.9: add narrower_nanbox_fpr helper, frank . chang, 2020/07/22
  - Re: [RFC v2 19/76] target/riscv: rvv-0.9: add narrower_nanbox_fpr helper, Richard Henderson, 2020/07/22
    - Re: [RFC v2 19/76] target/riscv: rvv-0.9: add narrower_nanbox_fpr helper, Frank Chang, 2020/07/23
    - Re: [RFC v2 19/76] target/riscv: rvv-0.9: add narrower_nanbox_fpr helper, Richard Henderson, 2020/07/23
- [RFC v2 20/76] target/riscv: rvv-0.9: apply narrower nanbox helper in opfvf_trans, frank . chang, 2020/07/22
- [RFC v2 21/76] target/riscv: rvv-0.9: configure instructions, frank . chang, 2020/07/22
  - Re: [RFC v2 21/76] target/riscv: rvv-0.9: configure instructions, Richard Henderson <=
- [RFC v2 22/76] target/riscv: rvv-0.9: stride load and store instructions, frank . chang, 2020/07/22
- [RFC v2 23/76] target/riscv: rvv-0.9: index load and store instructions, frank . chang, 2020/07/22
- [RFC v2 24/76] target/riscv: rvv-0.9: fix address index overflow bug of indexed load/store insns, frank . chang, 2020/07/22
- [RFC v2 25/76] target/riscv: rvv-0.9: fault-only-first unit stride load, frank . chang, 2020/07/22
- [RFC v2 26/76] target/riscv: rvv-0.9: amo operations, frank . chang, 2020/07/22
- [RFC v2 27/76] target/riscv: rvv-0.9: load/store whole register instructions, frank . chang, 2020/07/22
  - Re: [RFC v2 27/76] target/riscv: rvv-0.9: load/store whole register instructions, Richard Henderson, 2020/07/29
- [RFC v2 28/76] target/riscv: rvv-0.9: update vext_max_elems() for load/store insns, frank . chang, 2020/07/22
  - Re: [RFC v2 28/76] target/riscv: rvv-0.9: update vext_max_elems() for load/store insns, Richard Henderson, 2020/07/30
- [RFC v2 29/76] target/riscv: rvv-0.9: take fractional LMUL into vector max elements calculation, frank . chang, 2020/07/22

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