Register Addressing - NEC mPD780065 Series Preliminary User's Manual

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)
of an instruction word in the registered bank specified with the register bank select flag (RBS0 to 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]
'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 C register as r
INCW DE; when selecting DE register pair as rp
CHAPTER 3 CPU ARCHITECTURE
Identifier Description
r X, A, C, B, E, D, L, H
rp AX, BC, DE, HL
Operation code 0 1 1 0 0 0 1 0
Operation code 1 0 0 0 0 1 0 0
Preliminary User's Manual U13420EJ2V0UM00
Register specify code
Register specify code
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