Samsung S3F80JB - Manual (Page 200)

INSTRUCTION SET S3F80JB
6-72
RLC
— Rotate Left Through Carry
RLC dst
Operation: dst (0)
← C
C
← dst (7)
dst (n + 1)
← dst (n), n = 0–6
The contents of the destination operand with the carry flag are rotated left one bit position. The
initial value of bit 7 replaces the carry flag (C); the initial value of the carry flag replaces bit zero.
7 0
C
Flags: C: Set if the bit rotated from the most significant bit position (bit 7) was "1".
Z: Set if the result is "0"; cleared otherwise.
S: Set if the result bit 7 is set; cleared otherwise.
V: Set if arithmetic overflow occurred, that is, if the sign of the destination changed during
rotation; cleared otherwise.
D: Unaffected.
H: Unaffected.
Format:
Bytes Cycles Opcode
(Hex)
Addr Mode
dst
opc dst 2 4 10 R
4 11 IR
Examples: Given: Register 00H = 0AAH, register 01H = 02H, and register 02H = 17H, C = "0":
RLC 00H
→
Register 00H = 54H, C = "1"
RLC @01H
→
Register 01H = 02H, register 02H = 2EH, C = "0"
In the first example, if general register 00H has the value 0AAH (10101010B), the statement
"RLC 00H" rotates 0AAH one bit position to the left. The initial value of bit 7 sets the carry flag
and the initial value of the C flag replaces bit zero of register 00H, leaving the value 55H
(01010101B). The MSB of register 00H resets the carry flag to "1" and sets the overflow flag.