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2 general-purpose registers – NEC PD78F9488 User Manual

Page 61

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CHAPTER 3 CPU ARCHITECTURE

User’s Manual U15331EJ4V1UD

61

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).
Each register can be used as an 8-bit register, or two 8-bit registers in pairs can be used as a 16-bit register (AX,

BC, DE, and HL).

General-purpose registers can be described in terms of function names (X, A, C, B, E, D, L, H, AX, BC, DE, or HL)

or absolute names (R0 to R7 and RP0 to RP3).

Figure 3-14. General-Purpose Register Configuration

(a) Absolute names

R0

15

0

7

0

16-bit processing

8-bit processing

RP3

RP2

RP1

RP0

R1

R2

R3

R4

R5

R6

R7

(b) Function names

X

15

0

7

0

16-bit processing

8-bit processing

HL

DE

BC

AX

A

C

B

E

D

L

H

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