Atmel 8051 - Page 58

The 8051 Instruction Set
1-57 Atmel 8051 Microcontrollers Hardware Manual
4316B–8051–02/04
1.14.43 RR A
1.14.44 RRC A
Function: Rotate Accumulator Right
Description: The eight bits in the Accumulator are rotated one bit to the right. Bit 0 is rotated into the bit 7 position. No flags
are affected.
Example: The Accumulator holds the value 0C5H (11000101B). The following instruction,
RR A
leaves the Accumulator holding the value 0E2H (11100010B) with the carry unaffected.
Bytes: 1
Cycles: 1
Encoding: 00000011
Operation: RR
(A
n
) ← (A
n
+ 1) n = 0 - 6
(A
7
) ← (A
0
)
Function: Rotate Accumulator Right through Carry flag
Description: The eight bits in the Accumulator and the carry flag are together rotated one bit to the right. Bit 0 moves into the
carry flag; the original value of the carry flag moves into the bit 7 position. No other flags are affected.
Example: The Accumulator holds the value 0C5H (11000101B), the carry is zero. The following instruction,
RRC A
leaves the Accumulator holding the value 62 (01100010B) with the carry set.
Bytes: 1
Cycles: 1
Encoding: 00010011
Operation: RRC
(A
n
) ← (A
n
+ 1) n = 0 - 6
(A
7
) ← (C)
(C) ← (A
0
)