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

[Jiajie Chen]

On 2023/8/9 01:01, Richard Henderson wrote:
> 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.)


Yes, actually the LoongArch 32 Reduced (or "simplified la32") version is 
my final aim because we are making embedded LoongArch32 Reduced CPUs on 
FPGA for a competition, and supporting LoongArch 32 is the first step ahead.


> 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;
> }


Sure, I will use this way.


> r~