Assembler:Commands:COMISS
Revision as of 16:25, 25 March 2022 by Hanslhansl (talk | contribs)
command comiss operand1, operand2
Compares the single-precision floating-point (single-fp) value in the low doubleword of the first operand with the single-fp value in the low doubleword of the second operand and sets the status flags in the (E)FLAGS register.
The CF, ZF and PF flags are set according to the result (unordered, greater than, less than, or equal). The OF, SF and AF flags are set to 0.
Command Parameters
| Parameter | Description |
|---|---|
| operand1 | The first operand to compare. Must be a XMM register. |
| operand2 | The second operand to compare. May be an XMM register or a 32 bit memory location |
Resulting Flag State
| Parameters | ZF | PF | CF |
|---|---|---|---|
| operand1 < operand2 | 0 | 0 | 1 |
| operand1 = operand2 | 1 | 0 | 0 |
| operand1 > operand2 | 0 | 0 | 0 |
| unordered | 1 | 1 | 1 |
The unordered result is returned if either source operand is a NaN (QNaN or SNaN). The OF, SF and AF flags are set to 0.
Examples
comiss xmm2,xmm5
comiss xmm2,[eax]
comiss xmm0,[00123ABC]
