ARM VERSION 1.2 - Manual (Page 220)

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5-26 Copyright © 2000, 2001 ARM Limited. All rights reserved. ARM DUI 0068B
5.3.3 CMP and CMN
Compare and Compare Negative.
Syntax
CMP Rn, #expr
CMP Rn, Rm
CMN Rn, Rm
where:
Rn is the register containing the first operand.
expr is an expression that evaluates (at assembly time) to an integer in the
range 0-255.
Rm is a register containing the second operand.
Usage
These instructions update the condition flags, but do not place a result in a register.
The CMP instruction subtracts the value of expr , or the value in Rm , from the value in Rn .
The CMN instruction adds the values in Rm and Rn .
Restrictions
In CMP Rn,#expr , and CMN instructions, Rn and Rm must be in the range r0 to r7.
In CMP Rn,Rm instructions, Rn and Rm can be any register r0 to r15.
Condition flags
These instructions update the N, Z, C, and V flags according to the result.
Architectures
These instructions are available in all T variants of the architecture.