Description:

Clears a register. This instruction performs an Exclusive OR between a register and itself. This will clear all bits in the register.

Operation:

Rd ← Rd [+] Rd

Syntax: Operands: Program Counter:

CLR Rd 0 ≤ d ≤ 31 PC ← PC + 1

16-bit Opcode: (see EOR Rd,Rd)

0010

01dd

dddd

dddd

Status Register (SREG) and Boolean Formula:

I

T

H

S

V

N

Z

C

-

-

-

0

0

0

1

-

S: 0 Cleared

V:0 Cleared

N:0 Cleared

Z:1 Set

R (Result) equals Rd after the operation.

Example:

clr r18 ; clear r18
loop: inc r18 ; increase r18
...
cpi r18, $50 ; Compare r18 to $50
brne loop

Words: 1 (2 bytes)

Cycles: 1