Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet

115

SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14

Compare and Compare Negative.

Syntax

CMP{cond} Rn, Operand2

CMN{cond} Rn, Operand2

where:

cond

is an optional condition code, see 

.

Rn

is the register holding the first operand.

Operand2

is a flexible second operand. See 

 for details of the

options

Operation

These instructions compare the value in a register with Operand2. They update the condition flags on the result,
but do not write the result to a register.

The CMP instruction subtracts the value of Operand2 from the value in Rn. This is the same as a SUBS
instruction, except that the result is discarded.

The CMN instruction adds the value of Operand2 to the value in Rn. This is the same as an ADDS instruction,
except that the result is discarded.

Restrictions

In these instructions:



Do not use PC



Operand2 must not be SP.

Condition Flags

These instructions update the N, Z, C and V flags according to the result.

Examples

CMP

R2, R9

CMN

R0, #6400

CMPGT

SP, R7, LSL #2