a question about movss

[Alloy]

 In my debugger this

Code Select Expand


.data
    temp real4 2.0
.code
    movss xmm2,temp

doesn't just load the lowest xmm2 32 bit register but causes the upper 3 32 bit registers to reset to 0.0. Is this normal?

[arafel]

When the source and destination operands are XMM registers, the three high-order doublewords
of the destination operand remain unchanged. When the source operand is a memory location
and destination operand is an XMM registers, the three high-order doublewords of the destination
operand are cleared to all 0s.

[Alloy]

Thanks arafel.