CHAPTER 3 CPU ARCHITECTURE
User’s Manual U18172EJ2V0UD
47
3.4.4 Register addressing
[Function]
A general-purpose register is accessed as an operand.
The general-purpose register to be accessed is specified with the register specify code and functional name in
the instruction code.
Register addressing is carried out when an instruction with the following operand format is executed. When an
8-bit register is specified, one of the eight registers is specified with 3 bits in the instruction code.
[Operand format]
Identifier Description
r
X, A, C, B, E, D, L, H
rp
AX, BC, DE, HL
‘r’ and ‘rp’ can be described with absolute names (R0 to R7 and RP0 to RP3) as well as function names (X, A, C,
B, E, D, L, H, AX, BC, DE, and HL).
[Description example]
MOV A, C; When selecting the C register for r
Instruction
code 0 0
0
0
1
0
1
0
0
0
1
0
0
1
0
1
Register specify code
INCW DE; When selecting the DE register pair for rp
Instruction
code 1 0
0
0
1
0
0
0
Register specify code