Re: [Qemu-devel] [PATCH v5 43/76] target/mips: Add emulation of DSP ASE for nanoMIPS - part 6

[Richard Henderson]

On 07/31/2018 02:58 PM, Richard Henderson wrote:
> On 07/30/2018 12:12 PM, Aleksandar Markovic wrote:
>> +        switch (extract32(ctx->opcode, 12, 1)) {
>> +        case 0:
>> +            /* NM_SHRA_QB */
>> +            check_dspr2(ctx);
>> +            gen_helper_shra_qb(cpu_gpr[ret], t0, v1_t);
> More unprotected use of cpu_gpr[0].
> 
> I think you need some sort of solution that prevents this completely, without
> having to think about it.  E.g. global replace cpu_gpr[x] -> read_gpr(ctx, x) 
> /
> dest_gpr(ctx, x), where the two functions allocate tcg temporaries on demand.

I forgot to say... and then poison cpu_gpr so that uses cannot creep back into
the codebase.  See e.g. include/exec/poison.h.


r~