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3-126 Vol. 2A CMPPD—Compare Packed Double-Precision Floating-Point Values
INSTRUCTION SET REFERENCE, A-M
CMPPD—Compare Packed Double-Precision Floating-Point Values
Description
Performs a SIMD compare of the two packed double-precision floating-point values in
the source operand (second operand) and the destination operand (first operand)
and returns the results of the comparison to the destination operand. The compar-
ison predicate operand (third operand) specifies the type of comparison performed
on each of the pairs of packed values. The result of each comparison is a quadword
mask of all 1s (comparison true) or all 0s (comparison false).
The source operand can be an XMM register or a 128-bit memory location. The desti-
nation operand is an XMM register. The comparison predicate operand is an 8-bit
immediate, the first 3 bits of which define the type of comparison to be made (see
Table 3-7). Bits 4 through 7 of the immediate are reserved.
Opcode Instruction 64-Bit
Mode
Compat/
Leg Mode
Description
66 0F C2 /r ib CMPPD xmm1,
xmm2/m128, imm8
Valid Valid Compare packed double-
precision floating-point
values in xmm2/m128 and
xmm1 using imm8 as
comparison predicate.
Table 3-7. Comparison Predicate for CMPPD and CMPPS Instructions
Predi-
cate
imm8
Encod-
ing
Description Relation where:
A Is 1st Operand
B Is 2nd
Operand
Emulation Result if
NaN
Operand
QNaN
Oper-and
Signals
Invalid
EQ 000B Equal A
= BFalseNo
LT 001B Less-than A < BFalseYes
LE 010B Less-than-or-equal A
≤ BFalseYes
Greater than A
> BSwap
Operands,
Use LT
False Yes
Greater-than-or-
equal
A
≥ BSwap
Operands,
Use LE
False Yes
UNORD 011B Unordered A, B = Unordered True No
NEQ 100B Not-equal A ≠ BTrueNo
NLT 101B Not-less-than NOT(A
< B) True Yes