Re: [Qemu-ppc] [Qemu-devel] [PATCH 02/14] target/ppc: remove getVSR()/putVSR() from mem_helper.c

[Richard Henderson]

On 5/5/19 2:34 AM, Mark Cave-Ayland wrote:
>>>      EA = tcg_temp_new();                                        \
>>> -    xt = tcg_const_tl(xT(ctx->opcode));                         \
>>>      gen_set_access_type(ctx, ACCESS_INT);                       \
>>>      gen_addr_register(ctx, EA);                                 \
>>> -    gen_helper_##name(cpu_env, EA, xt, cpu_gpr[rB(ctx->opcode)]); \
>>> +    xt = tcg_const_tl(xT(ctx->opcode));                         \
>>> +    rb = tcg_const_tl(rB(ctx->opcode));                         \
>>> +    gen_helper_##name(cpu_env, EA, xt, rb);                     \
>>>      tcg_temp_free(EA);                                          \
>>>      tcg_temp_free(xt);                                          \
>>> +    tcg_temp_free(rb);                                          \
>>>  }
>>
>> Why are you adjusting the function to pass the rB register number rather than
>> the contents of rB?  That seems the wrong way around...
> 
> I think what I was trying to do here was eliminate the cpu_gpr since it
> feels to me that with the vector patchsets and your negative offset patches
> that this should be the way to go for accessing CPUState rather than using
> TCG globals.

Not for the integer register set.

> Looking at this again I realise the solution is really the same as is
> currently used
> for gen_load_spr() so I can use something like this:>
>     static inline void gen_load_gpr(TCGv t, int reg)
>     {
>         tcg_gen_ld_tl(t, cpu_env, offsetof(CPUPPCState, gpr[reg]));
>     }
> 
> Does this seem reasonable as a solution?

No, this will fail quickly.


r~