Xchb (Exchange Byte Data) - Fujitsu FR Family Instruction Manual

CHAPTER 7 DETAILED EXECUTION INSTRUCTIONS

7.135 XCHB (Exchange Byte Data)

Exchange the contents of the byte address indicated by "Rj" and those indicated by
"Ri".
The lower 8 bits of data originally at "Ri" is transferred to byte address indicated by
"Rj", and the data originally at "Rj" is extended with zeros and transferred to "Ri".
The CPU will not accept hold requests between the memory read operation and the
memory write operation of this instruction.
■ XCHB (Exchange Byte Data)
Assembler format: XCHB @Rj, Ri
Operation: Ri → TEMP
extu (Rj) → Ri
TEMP → (Rj)
Flag change:
N, Z, V, and C: Unchanged
Execution cycles: 2a cycles
Instruction format:
254
N Z V C
– – – –
MSB
1 0 0 0 1 0 1 0 Rj
LSB
Ri