Instruction Format; Generic Format (:G); Quick Format (:Q); Short Format (:S) - Renesas R8C/Tiny Series Software Manual

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 *2 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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1.9 Instruction Format
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