[fpc-devel] improvement SSE and string+char

[DarekM]

Florian Klaempfl pisze:
> DarekM schrieb:
>   
>> Hi
>> I've notice two improvement
>> 1. equation in SSE
>>
>> # Var Zr located in register mreg0md
>> # Var Zi located in register mreg1md
>> # Var Ti located in register mreg3md
>> # Var Tr located in register mreg2md
>> # [39] Tr := Zr * Zr;
>>    movsd    %xmm0,%xmm4
>>    mulsd    %xmm0,%xmm4
>>    movsd    %xmm4,%xmm2
>>
>> it can be changed to:
>> # [39] Tr := Zr * Zr;
>>    movsd    %xmm0,%xmm2
>>    mulsd    %xmm0,%xmm2
>>     
>
> Yes, but it's not easy to implement ;)
>   
I think so, but  its worth of effort. That are very popular equation 
(the same with A=B+C) . And second: can cpu then make own 
optimalizations (next line use different registers).

my stupid suggest:
  after translate of equation test of last line:
   movsd %xmmA,%xmmB

if %xmmB is not use before change every %xmmA to %xmmB and remove last line.

but sorry it I don't understand some of it.



Darek