INSTRUCTION SET S3F80P5_UM_ REV1.00
RRC — Rotate Right Through Carry
RRC dst
Operation: dst (7) ← C
C ← dst (0)
dst (n) ← dst (n + 1), n = 0–6
The contents of the destination operand and the carry flag are rotated right one bit position. The
initial value of bit zero (LSB) replaces the carry flag; the initial value of the carry flag replaces bit 7
(MSB).
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C
Flags: C: Set if the bit rotated from the least significant bit position (bit zero) 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 C0 R
4 C1 IR
Examples: Given: Register 00H = 55H, register 01H = 02H, register 02H = 17H, and C = "0":
RRC 00H → Register 00H = 2AH, C = "1"
RRC @01H → Register 01H = 02H, register 02H = 0BH, C = "1"
In the first example, if general register 00H contains the value 55H (01010101B), the statement
"RRC 00H" rotates this value one bit position to the right. The initial value of bit zero ("1")
replaces the carry flag and the initial value of the C flag ("1") replaces bit 7. This leaves the new
value 2AH (00101010B) in destination register 00H. The sign flag and overflow flag are both
cleared to "0".
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