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Re: [PATCH v2 14/15] target/riscv: csr: Remove compile time XLEN checks
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From: |
Richard Henderson |
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Subject: |
Re: [PATCH v2 14/15] target/riscv: csr: Remove compile time XLEN checks |
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Date: |
Wed, 9 Dec 2020 11:34:23 -0600 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 |
On 12/8/20 4:56 PM, Alistair Francis wrote:
> @@ -1053,11 +1077,11 @@ static int read_htimedelta(CPURISCVState *env, int
> csrno, target_ulong *val)
> return -RISCV_EXCP_ILLEGAL_INST;
> }
>
> -#if defined(TARGET_RISCV32)
> - *val = env->htimedelta & 0xffffffff;
> -#else
> - *val = env->htimedelta;
> -#endif
> + if (riscv_cpu_is_32bit(env)) {
> + *val = env->htimedelta & 0xffffffff;
> + } else {
> + *val = env->htimedelta;
> + }
> return 0;
> }
Certainly this mask was useless before the patch, because of the ifdef and
target_ulong.
Afterward, target_ulong may be larger than uint32_t... but what does the rest
of the value, and the register into which it is stored, represent?
Are you going to keep the register values sign-extended, as-if by addw et al,
in which case casting to int32_t would be better. Are you going to simply
ignore the upper 32 bits, in which case dropping the masking entirely would be
better.
r~
- Re: [PATCH v2 10/15] target/riscv: Add a riscv_cpu_is_32bit() helper function, (continued)
- [PATCH v2 11/15] target/riscv: Specify the XLEN for CPUs, Alistair Francis, 2020/12/08
- [PATCH v2 12/15] target/riscv: cpu: Remove compile time XLEN checks, Alistair Francis, 2020/12/08
- [PATCH v2 13/15] target/riscv: cpu_helper: Remove compile time XLEN checks, Alistair Francis, 2020/12/08
- [PATCH v2 14/15] target/riscv: csr: Remove compile time XLEN checks, Alistair Francis, 2020/12/08
- Re: [PATCH v2 14/15] target/riscv: csr: Remove compile time XLEN checks,
Richard Henderson <=
- [PATCH v2 15/15] target/riscv: cpu: Set XLEN independently from target, Alistair Francis, 2020/12/08
- Re: [PATCH v2 00/15] RISC-V: Start to remove xlen preprocess, Palmer Dabbelt, 2020/12/14