Assembler Language Reference

cmp (Compare) Instruction

Purpose

Compares the contents of two general-purpose registers algebraically.

Syntax

Bits	Value
0-5	31
6-8	BF
9	/
10	L
11-15	RA
16-20	RB
21-30	0
31	/

cmp	BF, L, RA, RB

See Extended Mnemonics of Fixed-Point Compare Instructions for more information.

Description

The cmp instruction compares the contents of general-purpose register (GPR) RA with the contents of GPR RB as signed integers and sets one of the bits in Condition Register Field BF.

BF can be Condition Register Field 0-7; programmers can specify which Condition Register Field will indicate the result of the operation.

The bits of Condition Register Field BF are interpreted as follows:

Bit	Name	Description
0	LT	(RA) < SI
1	GT	(RA) > SI
2	EQ	(RA) = SI
3	SO	SO,OV

The cmp instruction has one syntax form and does not affect the Fixed-Point Exception Register. Condition Register Field 0 is unaffected unless it is specified as BF by the programmer.

Parameters

BF	Specifies Condition Register Field 0-7 which indicates result of compare.
L	Must be set to 0 for the 32-bit subset architecture.
RA	Specifies source general-purpose register for operation.
RB	Specifies source general-purpose register for operation.

Examples

The following code compares the contents of GPR 4 and GPR 6 as signed integers and sets Condition Register Field 0 to reflect the result of the operation:

# Assume GPR 4 contains 0xFFFF FFE7.
# Assume GPR 5 contains 0x0000 0011.
# Assume 0 is Condition Register Field 0.
cmp 0,4,6
# The LT bit of Condition Register Field 0 is set.

Related Information

The cmpi (Compare Immediate) instruction, cmpl (Compare Logical) instruction, cmpli (Compare Logical Immediate) instruction.

Fixed-Point Processor .