CHAPTER 3 CPU ARCHITECTURE
3.2.2 General-purpose registers
The general-purpose registers consist 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 described 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 3-12. General-Purpose Register Configuration
(a) Absolute Names
16-bit processing
RP3
RP2
RP1
RP0
15
0
8-bit processing
R7
R6
R5
R4
R3
R2
R1
R0
7
0
(b) Functional Names
16-bit processing
HL
DE
BC
AX
15
0
8-bit processing
H
L
D
E
B
C
A
X
7
0
38
User’s Manual 2nd edition