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S3C80A5B
RR
— Rotate Right
RR
dst
C ←?dst (0)
Operation:
dst (7) ← dst (0)
dst (n? ? ? ? ←
The contents of the destination operand are rotated right one bit position. The initial value of bit zero
(LSB) is moved to bit 7 (MSB) and also replaces the carry flag (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:
opc
Examples:
Given: Register 00H = 31H, register 01H = 02H, and register 02H = 17H:
RR
RR
In the first example, if general register 00H contains the value 31H (00110001B), the statement "RR
00H" rotates this value one bit position to the right. The initial value of bit zero is moved to bit 7,
leaving the new value 98H (10011000B) in the destination register. The initial bit zero also resets the
C flag to "1" and the sign flag and overflow flag are also set to "1".
dst (n + 1), n = 0–6
C
dst
00H
?
Register 00H = 98H, C = "1"
@01H
?
Register 01H = 02H, register 02H = 8BH, C = "1"
7
0
Bytes
2
INSTRUCTION SET
Cycles
Opcode
(Hex)
4
E0
4
E1
Addr Mode
dst
R
IR
6-73
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