Z8F082ASJ020EG Datasheet, PDF (221/282 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
204
eZ8 CPU Instruction Set
This chapter describes the following features of the eZ8 CPU instruction set:
Assembly Language Programming Introduction: see page 204
Assembly Language Syntax: see page 205
eZ8 CPU Instruction Notation: see page 206
eZ8 CPU Instruction Classes: see page 207
eZ8 CPU Instruction Summary: see page 212
Assembly Language Programming Introduction
The eZ8 CPU assembly language provides a means for writing an application program
without concern for actual memory addresses or machine instruction formats. A program
written in assembly language is called a source program. Assembly language allows the
use of symbolic addresses to identify memory locations. It also allows mnemonic codes
(opcodes and operands) to represent the instructions themselves. The opcodes identify the
instruction while the operands represent memory locations, registers, or immediate data
values.
Each assembly language program consists of a series of symbolic commands called state-
ments. Each statement can contain labels, operations, operands and comments.
Labels can be assigned to a particular instruction step in a source program. The label iden-
tifies that step in the program as an entry point for use by other instructions.
The assembly language also includes assembler directives that supplement the machine
instruction. The assembler directives, or pseudo-ops, are not translated into a machine
instruction. Rather, the pseudo-ops are interpreted as directives that control or assist the
assembly process.
The source program is processed (assembled) by the assembler to obtain a machine lan-
guage program called the object code. The object code is executed by the eZ8 CPU. An
example segment of an assembly language program is detailed in the following example.
PS022827-1212
PRELIMINARY
eZ8 CPU Instruction Set