Renesas Renasas Single-Chip Microcomputer SH7086 Bedienungsanleitung PDF herunterladen (Seite 36)

Chapter 1 Overview

1.9 Instruction Format

The instruction format can be classified into four types: generic, quick, short, and zero. The number of

instruction bytes that can be chosen by a given format is least for the zero format, and increases succes-

sively for the short, quick, and generic formats in that order.

The following describes the features of each format.

1.9.1 Generic format (:G)

Op-code in this format consists of two bytes. This op-code contains information on operation and src

and dest

addressing modes.

Instruction code here is comprised of op-code (2 bytes), src code (0-3 bytes), and dest code (0-3 bytes).

1.9.2 Quick format (:Q)

Op-code in this format consists of two bytes. This op-code contains information on operation and imme-

diate data and dest addressing modes. Note however that the immediate data in this op-code is a

numeric value that can be expressed by -7 to +8 or -8 to +7 (varying with instruction).

Instruction code here is comprised of op-code (2 bytes) containing immediate data and dest code (0-2

bytes).

1.9.3 Short format (:S)

Op-code in this format consists of one byte. This op-code contains information on operation and src and

dest addressing modes.Note however that the usable addressing modes are limited.

Instruction code here is comprised of op-code (1 byte), src code (0-2 bytes), and dest code (0-2 bytes).

1.9.4 Zero format (:Z)

Op-code in this format consists of one byte. This op-code contains information on operation (plus

immediate data) and dest addressing modes. Note however that the immediate data is fixed to 0, and

that the usable addressing modes are limited.

Instruction code here is comprised of op-code (1 byte) and dest code (0-2 bytes).

*1 src is the abbreviation of “source.”

*2 dest is the abbreviation of “destination.”

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Renesas Renasas Single-Chip Microcomputer SH7086 Bedienungsanleitung Seite 36