Swap – Samsung S3C8275X User Manual
Page 217
S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X
INSTRUCTION SET
6-83
SWAP
—
Swap Nibbles
SWAP
dst
Operation:
dst (0 – 3)
↔ dst (4 – 7)
The contents of the lower four bits and upper four bits of the destination operand are swapped.
7
0
4 3
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:
Bytes
Cycles
Opcode
(Hex)
Addr Mode
dst
opc
dst
2
4
F0 R
4
F1
IR
Examples:
Given: Register 00H = 3EH, register 02H = 03H, and register 03H = 0A4H:
SWAP 00H
→
Register 00H = 0E3H
SWAP @02H
→
Register 02H = 03H, register 03H = 4AH
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).