CMPPD—Compare Packed Double-Precision Floating-Point Values

INSTRUCTION SET REFERENCE, A-L

Vol. 2A 3-155

VEX.128 encoded version: The first source operand (second operand) is an XMM register. The second source 
operand (third operand) can be an XMM register or a 128-bit memory location. Bits (MAX_VL-1:128) of the desti-
nation ZMM register are zeroed. Two comparisons are performed with results written to bits 127:0 of the destina-
tion operand.
The comparison predicate operand is an 8-bit immediate:

•

For instructions encoded using the VEX or EVEX prefix, bits 4:0 define the type of comparison to be performed 
(see Table 3-1). Bits 5 through 7 of the immediate are reserved. 

•

For instruction encodings that do not use VEX prefix, bits 2:0 define the type of comparison to be made (see 
the first 8 rows of Table 3-1). Bits 3 through 7 of the immediate are reserved. 

Table 3-1. Comparison Predicate for CMPPD and CMPPS Instructions 

Predicate

imm8 

Value

Description

Result: A Is 1st Operand, B Is 2nd Operand Signals 

#IA on 

QNAN

A >B

A < B

A = B

Unordered

1

EQ_OQ (EQ)

0H

Equal (ordered, non-signaling)

False

False

True

False

No

LT_OS (LT)

1H

Less-than (ordered, signaling)

False

True

False

False

Yes

LE_OS (LE)

2H

Less-than-or-equal (ordered, signaling)

False

True

True

False

Yes

UNORD_Q (UNORD) 3H

Unordered (non-signaling)

False

False

False

True

No

NEQ_UQ (NEQ)

4H

Not-equal (unordered, non-signaling)

True

True

False

True

No

NLT_US (NLT)

5H

Not-less-than (unordered, signaling)

True

False

True

True

Yes

NLE_US (NLE)

6H

Not-less-than-or-equal (unordered, signaling) True

False

False

True

Yes

ORD_Q (ORD)

7H

Ordered (non-signaling)

True

True

True

False

No

EQ_UQ

8H

Equal (unordered, non-signaling)

False

False

True

True

No

NGE_US (NGE)

9H

Not-greater-than-or-equal (unordered, 

signaling)

False

True

False

True

Yes

NGT_US (NGT)

AH

Not-greater-than (unordered, signaling)

False

True

True

True

Yes

FALSE_OQ(FALSE)

BH

False (ordered, non-signaling)

False

False

False

False

No

NEQ_OQ

CH

Not-equal (ordered, non-signaling)

True

True

False

False

No

GE_OS (GE)

DH

Greater-than-or-equal (ordered, signaling)

True

False

True

False

Yes

GT_OS (GT)

EH

Greater-than (ordered, signaling)

True

False

False

False

Yes

TRUE_UQ(TRUE)

FH

True (unordered, non-signaling)

True

True

True

True

No

EQ_OS

10H

Equal (ordered, signaling)

False

False

True

False

Yes

LT_OQ

11H

Less-than (ordered, nonsignaling)

False

True

False

False

No

LE_OQ

12H

Less-than-or-equal (ordered, nonsignaling)

False

True

True

False

No

UNORD_S

13H

Unordered (signaling)

False

False

False

True

Yes

NEQ_US

14H

Not-equal (unordered, signaling)

True

True

False

True

Yes

NLT_UQ

15H

Not-less-than (unordered, nonsignaling)

True

False

True

True

No

NLE_UQ

16H

Not-less-than-or-equal (unordered, nonsig-

naling)

True

False

False

True

No

ORD_S

17H

Ordered (signaling)

True

True

True

False

Yes

EQ_US

18H

Equal (unordered, signaling)

False

False

True

True

Yes

NGE_UQ

19H

Not-greater-than-or-equal (unordered, non-

signaling)

False

True

False

True

No