Re: [PATCH v4 01/11] target/loongarch: Add macro to check current arch

[Richard Henderson]

On 8/7/23 18:54, Jiajie Chen wrote:
> Add macro to check if the current cpucfg[1].arch equals to 1(LA32) or
> 2(LA64).
>
> Signed-off-by: Jiajie Chen <c@jia.je>
> ---
>   target/loongarch/cpu.h | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
> index fa371ca8ba..bf0da8d5b4 100644
> --- a/target/loongarch/cpu.h
> +++ b/target/loongarch/cpu.h
> @@ -132,6 +132,13 @@ FIELD(CPUCFG1, HP, 24, 1)
>   FIELD(CPUCFG1, IOCSR_BRD, 25, 1)
>   FIELD(CPUCFG1, MSG_INT, 26, 1)
>   
> +/* cpucfg[1].arch */
> +#define CPUCFG1_ARCH_LA32        1
> +#define CPUCFG1_ARCH_LA64        2
> +
> +#define LOONGARCH_CPUCFG_ARCH(env, mode) \
> +  (FIELD_EX32(env->cpucfg[1], CPUCFG1, ARCH) == CPUCFG1_ARCH_##mode)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

But in using this recall that 0 is a defined value for "simplified la32", so

   !LOONGARCH_CPUCFG_ARCH(env, LA64)

may not in future equal

   LOONGARCH_CPUCFG_ARCH(env, LA32)

it someone ever decides to implement this simplified version. (We emulate very small 
embedded Arm cpus, so it's not out of the question that you may want to emulate the very 
smallest LoongArch cpus.)

It might be easier to just define

static inline bool is_la64(CPULoongArch64 *env)
{
    return FIELD_EX32(env->cpucfg[1], CPUCFG1, ARCH) == CPUCFG1_ARCH_LA64;
}


r~