MB89120 データシートの表示（PDF） - Fujitsu

部品番号

コンポーネント説明

メーカー

MB89120

8-bit Proprietary Microcontroller

Fujitsu 

MB89120/120A Series

2. Registers

The F2MC-8L family has two types of registers; dedicated hardware registers and general-purpose memory

registers. The following dedicated registers are provided :

Program counter (PC) :

A 16-bit-long register for indicating the instruction storage positions

Accumulator (A) :

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

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

Temporary accumulator (T) : A 16-bit-long register which is used for arithmetic operations with the accumu-

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

byte is used.

Index register (IX) :

A 16-bit-long register for index modification

Extra pointer (EP) :

A 16-bit-long pointer for indicating a memory address

Stack pointer (SP) :

A 16-bit-long pointer for indicating a stack area

Program status (PS) :

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

16 bits

PC

A

T

IX

EP

SP

PS

Initial value

: Program counter

FFFDH

: Accumulator

Indeterminate

: Temporary accumulator Indeterminate

: Index register

Indeterminate

: Extra pointer

Indeterminate

: Stack pointer

Indeterminate

: Program status

I-flag = 0, IL1, 0 = 11

The other bit values are Indeterminate.

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 5 4 3 2 1 0

PS

RP

Vacancy Vacancy Vacancy H

I

IL1, 0

NZVC

RP

CCR

19

Share Link: