Re: [PATCH v2 03/24] target/mips/cpu: Introduce isa_rel6_available() helper

[Philippe Mathieu-Daudé]

On 12/16/20 12:27 AM, Richard Henderson wrote:
> On 12/15/20 4:57 PM, Philippe Mathieu-Daudé wrote:
>> +bool isa_rel6_available(const CPUMIPSState *env)
>> +{
>> +    if (TARGET_LONG_BITS == 64) {
>> +        return cpu_supports_isa(env, ISA_MIPS64R6);
>> +    }
>> +    return cpu_supports_isa(env, ISA_MIPS32R6);
>> +}
> 
> So... does qemu-system-mips64 support 32-bit cpus?

Well... TBH I never tested it :S It looks the TCG code
is compiled with 64-bit TL registers, the machine address
space is 64-bit regardless the CPU, and I see various
#ifdef MIPS64 code that look dubious with 32-bit CPU.

> 
> If so, this needs to be written
> 
>   if (TARGET_LONG_BITS == 64 && cpu_supports_isa(...)) {
>     return true;
>   }
> 
> Otherwise, this will return false for a mips32r6 cpu.

I see. Rel6 is new to me, so I'll have to look at the ISA
manuals before returning to this thread with an answer.

Thanks for reviewing the series!

Phil.