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

Chapter 1 Overview

1.9 Instruction Formats

The instruction formats 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 features of each format are described below.

1.9.1 Generic Format (:G)

The op-code in this format comprises two bytes. This op-code contains information on the operation
and the src *1 and dest
The instruction code is composed of op-code (2 bytes), src code (0 to 3 bytes), and dest code (0 to 3
bytes).

1.9.2 Quick Format (:Q)

The op-code in this format comprises two bytes. This op-code contains information on the operation
and the immediate data and dest addressing modes. Note, however, that the immediate data in the op-
code is a numeric value that can be expressed as -7 to +8 or -8 to +7 (depending on the instruction).
The instruction code is composed of op-code (2 bytes) containing immediate data and dest code (0 to 2
bytes).

1.9.3 Short Format (:S)

The op-code in this format comprises one byte. This op-code contains information on the operation and
the src and dest addressing modes. Note, however, that the usable addressing modes are limited.
The instruction code is composed of op-code (1 byte), src code (0 to 2 bytes), and dest code (0 to 2
bytes).

1.9.4 Zero Format (:Z)

The op-code in this format comprises one byte. This op-code contains information on the operation
(plus immediate data) and dest addressing modes. Note, however, that the immediate data is fixed at 0,
and that the usable addressing modes are limited.
The instruction code is composed of op-code (1 byte) and dest code (0 to 2 bytes).
*1 src is an abbreviation of "source."
*2 dest is an abbreviation of "destination."
Rev.2.00 Oct 17, 2005
REJ09B0001-0200
*2 addressing modes.
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1.9 Instruction Formats