NEC mPD780852 Series, Preliminary User'S Manual

Page: 67 / 315

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CHAPTER 3 CPU ARCHITECTURE
Preliminary User’s Manual U14581EJ3V0UM00
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