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General Forums => The Campus => Topic started by: Alloy on April 28, 2006, 10:13:09 PM

Title: a question about movss
Post by: Alloy on April 28, 2006, 10:13:09 PM
 In my debugger this

.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?
Title: Re: a question about movss
Post by: arafel on April 28, 2006, 10:31:58 PM
Quote from: Intel instruction set reference (movss)

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.

Title: Re: a question about movss
Post by: Alloy on April 29, 2006, 02:16:47 AM
Thanks arafel.