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assemblyx86simdsse

Push XMM register to the stack

Is there a way of pushing a packed doubleword integer from XMM register to the stack? and then later on pop it back when needed?

Ideally I am looking for something like PUSH or POP for general purpose registers, I have checked Intel manuals but I either missed the command or there isn't one...

Or will I have to unpack values to general registers and then push them?

Solution

  • No, there is no such a asm instruction under x86, but you can do something like:

    //Push xmm0
sub     esp, 16
movdqu  dqword [esp], xmm0

//Pop xmm0
movdqu  xmm0, dqword [esp]
add     esp, 16

    EDIT:

    Upper code sample is direct push/pop emulation.

    In case that you are using on stack also other local variables, than the ebp register must be at first properly set, like:

    push ebp
mov  ebp, esp
sub  esp, LocaStackVariablesSize
//... your code
mov  esp, ebp
pop  ebp  
ret

    In that case you can also use Daniels solution!