Is there an alternate way to put a qword in an mmx register?
For example, in this code snippet:
db random 0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa,0xaa
run:
movq mm2, [rel random]
I can now work with that as a qword 0xaaaaaaaaaaaaaaaa and do pxor etc with it. Is there some other way I could put that data in the register? Maybe by pushing/popping to it?
No idea why you want to do this, but you can avoid movq if you zero the register and then bring in the value using some operation, such as:
pxor mm2, mm2
pxor mm2, [rel random]
Alternatively, you can load the words using pinsrw:
pinsrw mm2, [rel random], 0
pinsrw mm2, [rel random + 2], 1
pinsrw mm2, [rel random + 4], 2
pinsrw mm2, [rel random + 6], 3
This approach also works in reverse using pextrw but have to go through a general purpose register:
pextrw eax, mm2, 0
mov [rel random], ax
pextrw eax, mm2, 1
mov [rel random + 2], ax
pextrw eax, mm2, 2
mov [rel random + 4], ax
pextrw eax, mm2, 3
mov [rel random + 6], ax
If only movq must be avoided but maskmovq can be used then you can do:
pcmpeqb mm1, mm1
lea rdi, [rel random]
maskmovq mm2, mm1