Thank You for the explanation!
But my tests has different results:
void* SSE_sobelRow(ubyte* src, ubyte* dst, size_t srcStride){ asm{
push RDI;
mov RAX, 0; mov RDX, 0; mov RCX, 0; //clear 'parameter'
registers
mov RAX, src;
mov RDI, dst;
//gen
movups XMM0,[RAX];
movaps XMM1,XMM0;
pslldq XMM0,1;
movaps XMM2,XMM1;
psrldq XMM1,1;
pavgb XMM1,XMM0;
pavgb XMM1,XMM2;
movups [RDI],XMM1;
//gen end
pop RDI;
}}
When I clear those volatile regs that are used for register
calling, I'm still able to get good results.
However when I put "mov [RBP+8], 0" into the code it generates an
access violation, so this is why I think parameters are on the
stack.
What I'm really unsire is that the registers I HAVE TO save in my
asm routine.
Currently I think I only able to trash the contents of RAX, RCX,
RDX, XMM0..XMM5 based on the Microsoft calling model. But I'm not
sure what's the actual case with LDC2 Win64.
If my code is surrounded by SSE the optimizations of the LDC2
compiler, and I can't satisfy the requirements, I will have
random errors in the future. I better avoid those.
On the 32bit target the rule is simpe: you could do with all the
XMM regs and a,c,d what you want. Now at 64bit I'm quite unsure.
:S
