MB89470 データシートの表示（PDF） - Fujitsu

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MB89470

8-bit Proprietary Microcontroller

Fujitsu 

MB89470 Series

2. Registers

The F2MC-8L family has two types of registers; dedicated registers in the CPU and general-purpose registers

in the memory. The following registers are provided :

Program counter (PC)

: A 16-bit register for indicating instruction storage positions

Accumulator (A)

: A 16-bit temporary register for storing arithmetic operations, etc. When the

instruction is an 8-bit data processing instruction, the lower byte is used.

Temporary accumulator (T) : A 16-bit register which performs arithmetic operations with the accumulator.

When the instruction is an 8-bit data processing instruction, the lower byte is

used.

Index register (IX)

: A 16-bit register for index modification

Extra pointer (EP)

: A 16-bit pointer for indicating a memory address

Stack pointer (SP)

: A 16-bit register for indicating a stack area

Program status (PS)

: A 16-bit register for storing a register pointer, a condition code

16 bits

PC

A

T

IX

EP

SP

PS

: Program counter

Initial value

FFFDH

: Accumulator

Undefined

: Temporary accumulator

Undefined

: Index register

Undefined

: Extra pointer

Undefined

: Stack pointer

Undefined

: Program status

I-flag = 0, IL1, 0 = 11

Other bits are undefined.

The PS can further be divided into higher 8 bits for use as a register bank pointer (RP) and the lower 8 bits for

use as a condition code register (CCR) . (See the diagram below.)

Structure of the Program Status Register

15 14 13 12 11 10 9 8 7

6

54

3

21

0

PS

RP

Vacancy Vacancy Vacancy H

I

IL1, 0

N ZV C

RP

CCR

19

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