NEC 78K/0 Series - Manual (Page 25)

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CHAPTER 3 ADDRESSING
User's Manual U12326EJ4V0UM
3.2.2 Register addressing
[Function]
Register addressing accesses a general-purpose register as an operand. The general-purpose register to
be accessed is specified by the register bank selection flags (RBS0 and RBS1) and the register specification
codes (Rn and RPn) in the instruction codes.
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 by 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 1 1 0 0 0 1 0
INCW DE; When selecting the DE register pair for rp
Instruction code 1 0 0 0 0 1 0 0
Register specification code
Register specification code