NEC PD75P402, PD75402A user manual Internal CPU Functions General Register .... × 4 Bits

CHAPTER 4. INTERNAL CPU FUNCTIONS

4.4GENERAL REGISTER ..... 4 × 4 BITS

The general register is assigned to a specific address of the data memory. There are four 4-bit registers (H, L, X, A).

While each general register is operated per 4 bits, HL and XA make up register pairs, each of which is operated per 8 bits. The HL register pair is available as the data pointer to indirectly address the memory.

The general register area can be addressed and accessed as an ordinary RAM regardless of whether it is used as a register or not.

Fig. 4-4 General Register Configuration

X	A
0 1 H	0 0 H
H	L
0 3 H	0 2 H

Remarks The figure in the lower right corner is the assigned data memory address.

Fig. 4-5 Register Pair Configuration

30

H

30

L

30

X

30

A

35