Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO データシート

175

SAM4E [DATASHEET]

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

Compare and Branch on Zero, Compare and Branch on Non-Zero.

Syntax

CBZ Rn, label

CBNZ Rn, label

where:

Rn

is the register holding the operand.

label

is the branch destination.

Operation

Use the CBZ or CBNZ instructions to avoid changing the condition code flags and to reduce the number of
instructions. 

CBZ Rn, label does not change condition flags but is otherwise equivalent to:

CMP

Rn, #0

BEQ

label

CBNZ Rn, label does not change condition flags but is otherwise equivalent to:

CMP

Rn, #0

BNE

label

Restrictions

The restrictions are:



Rn must be in the range of R0 to R7



The branch destination must be within 4 to 130 bytes after the instruction



These instructions must not be used inside an IT block.

Condition Flags

These instructions do not change the flags.

Examples

CBZ

R5, target

; Forward branch if R5 is zero

CBNZ

R0, target  ; Forward branch if R0 is not zero