Re: [Qemu-devel] [PATCH v3 03/10] target/ppc: support for 32-bit carry and overflow

[Nikunj A Dadhania]

Richard Henderson <address@hidden> writes:

> Bah.  Hit return too soon...
>
> On 02/22/2017 10:44 PM, Nikunj A Dadhania wrote:
>> -static void gen_read_xer(TCGv dst)
>> +static void gen_read_xer(DisasContext *ctx, TCGv dst)
>>  {
>>      TCGv t0 = tcg_temp_new();
>>      TCGv t1 = tcg_temp_new();
>> @@ -3715,15 +3719,30 @@ static void gen_read_xer(TCGv dst)
>>      tcg_gen_or_tl(t0, t0, t1);
>>      tcg_gen_or_tl(dst, dst, t2);
>>      tcg_gen_or_tl(dst, dst, t0);
>> +    if (is_isa300(ctx)) {
>> +        tcg_gen_shli_tl(t0, cpu_ov32, XER_OV32);
>> +        tcg_gen_or_tl(dst, dst, t0);
>> +        tcg_gen_shli_tl(t0, cpu_ca32, XER_CA32);
>> +        tcg_gen_or_tl(dst, dst, t0);
>> +    }
>>      tcg_temp_free(t0);
>>      tcg_temp_free(t1);
>>      tcg_temp_free(t2);
>>  }
>>
>> -static void gen_write_xer(TCGv src)
>> +static void gen_write_xer(DisasContext *ctx, TCGv src)
>>  {
>> -    tcg_gen_andi_tl(cpu_xer, src,
>> -                    ~((1u << XER_SO) | (1u << XER_OV) | (1u << XER_CA)));
>> +    if (is_isa300(ctx)) {
>> +        tcg_gen_andi_tl(cpu_xer, src,
>> +                        ~((1u << XER_SO) |
>> +                          (1u << XER_OV) | (1u << XER_OV32) |
>> +                          (1u << XER_CA) | (1u << XER_CA32)));
>> +        tcg_gen_extract_tl(cpu_ov32, src, XER_OV32, 1);
>> +        tcg_gen_extract_tl(cpu_ca32, src, XER_CA32, 1);
>> +    } else {
>> +        tcg_gen_andi_tl(cpu_xer, src,
>> +                        ~((1u << XER_SO) | (1u << XER_OV) | (1u << 
>> XER_CA)));
>> +    }
>>      tcg_gen_extract_tl(cpu_so, src, XER_SO, 1);
>>      tcg_gen_extract_tl(cpu_ov, src, XER_OV, 1);
>>      tcg_gen_extract_tl(cpu_ca, src, XER_CA, 1);
>
> These functions are becoming quite large.  Are they performance critical 
> enough 
> that they need to stay as inline code, or should they be moved to helpers and 
> share code with cpu_read/write_xer?

Just to boot to login prompt, these are the numbers for gen_read/write_xer:

helper_myprint - rd_count 231103, wr_count 68897

And it keeps on incrementing, maybe scope of optimization here.

Regards
Nikunj