59
CHAPTER 3 CPU ARCHITECTURE
3.4.2 Register addressing
[Function]
The general register to be specified is accessed as an operand with the register specify code (Rn and RPn) in
an operation code and with the register bank select flags (RBS0 and RBS1).
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 operation 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 function names (X, A, C, B, E, D, L, H, AX, BC, DE and HL) as well as absolute
names (R0 to R7 and RP0 to RP3).
[Description example]
MOV A, C; when selecting C register as r
Operation code
0 1 1 0 0 0 1 0
Register specify code
INCW DE; when selecting DE register pair as rp
Operation code
1 0 0 0 0 1 0 0
Register specify code
Summary of Contents for mPD780973 Series
Page 2: ...2 MEMO ...
Page 66: ...66 MEMO ...
Page 98: ...98 MEMO ...
Page 138: ...138 MEMO ...
Page 164: ...164 MEMO ...
Page 182: ...182 MEMO ...
Page 204: ...204 MEMO ...
Page 244: ...244 MEMO ...
Page 262: ...262 MEMO ...
Page 278: ...278 MEMO ...
Page 290: ...290 MEMO ...