Atmel 8051 - Page 57

The 8051 Instruction Set
Atmel 8051 Microcontrollers Hardware Manual 1-56
4316B–8051–02/04
1.14.41 RL A
1.14.42 RLC A
Function: Rotate Accumulator Left
Description: The eight bits in the Accumulator are rotated one bit to the left. Bit 7 is rotated into the bit 0 position. No flags are
affected.
Example: The Accumulator holds the value 0C5H (11000101B). The following instruction,
RL A
leaves the Accumulator holding the value 8BH (10001011B) with the carry unaffected.
Bytes: 1
Cycles: 1
Encoding: 00100011
Operation: RL
(A
n
+ 1) ← (A
n
) n = 0 - 6
(A
0
) ← (A
7
)
Function: Rotate Accumulator Left through the Carry flag
Description: The eight bits in the Accumulator and the carry flag are together rotated one bit to the left. Bit 7 moves into the
carry flag; the original state of the carry flag moves into the bit 0 position. No other flags are affected.
Example: The Accumulator holds the value 0C5H(11000101B), and the carry is zero. The following instruction,
RLC A
leaves the Accumulator holding the value 8BH (10001010B) with the carry set.
Bytes: 1
Cycles: 1
Encoding: 00110011
Operation: RLC
(A
n
+ 1) ← (A
n
) n = 0 - 6
(A
0
) ← (C)
(C) ← (A
7
)