NEC mPD789026 Subseries, User Manual

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CHAPTER 3 CPU ARCHITECTURE
User's Manual U11919EJ3V0UM00
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3.2.2 General-purpose registers
A general-purpose register consists of eight 8-bit registers (X, A, C, B, E, D, L, and H).
In addition that each register can be used as an 8-bit register, two 8-bit registers in pairs can be used as a 16-bit
register (AX, BC, DE, and HL).
They can be written in terms of functional names (X, A, C, B, E, D, L, H, AX, BC, DE, and HL) and absolute
names (R0 to R7 and RP0 to RP3).
Figure 3-16. General-Purpose Register Configuration
(a) Absolute Names
(b) Functional Names
R0
15 0 7 0
16-Bit Processing 8-Bit Processing
RP3
RP2
RP1
RP0
R1
R2
R3
R4
R5
R6
R7
X
15 0 7 0
16-Bit Processing 8-Bit Processing
HL
DE
BC
AX
A
C
B
E
D
L
H