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S3C80A5B
SWAP
— Swap Nibbles
SWAP
dst
dst (0 – 3) ← dst (4 – 7)
Operation:
The contents of the lower four bits and upper four bits of the destination operand are swapped.
Flags:
C: Undefined.
Z: Set if the result is "0"; cleared otherwise.
S: Set if the result bit 7 is set; cleared otherwise.
V: Undefined.
D: Unaffected.
H: Unaffected.
Format:
opc
Examples:
Given: Register 00H = 3EH, register 02H = 03H, and register 03H = 0A4H:
SWAP
SWAP
In the first example, if general register 00H contains the value 3EH (00111110B), the statement
"SWAP 00H" swaps the lower and upper four bits (nibbles) in the 00H register, leaving the value
0E3H (11100011B).
7
dst
00H
?
Register 00H = 0E3H
@02H
?
Register 02H = 03H, register 03H = 4AH
4 3
0
Bytes
Cycles
2
INSTRUCTION SET
Opcode
Addr Mode
(Hex)
4
F0
4
F1
dst
R
IR
6-83
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