Zilog Z8F0130 - Manual (Page 62)

eZ8
™
CPU Core
User Manual
UM012820-0810 eZ8
™
CPU Instruction Set Summary
47
eZ8
™
CPU Instruction Set
Summary
eZ8 CPU assembly language enables writing to an application program
without concern about actual memory addresses or machine instruction
formats. A program written in assembly language is called a source
program. Assembly language uses symbolic addresses to identify memory
locations. It also allows mnemonic codes (Op Codes and operands) to
represent the instructions themselves. The Op Codes 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 statements. Each statement contains labels, operations,
operands and comments.
Labels are assigned to a particular instruction step in a source program.
The label identifies 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-
operations, are not translated into a machine instruction. The pseudo-
operations are interpreted as directives that control or assist the assembly
process.
The assembler processes the source program to obtain a machine
language program called the object code. The eZ8 CPU executes the
object code. An example segment of an assembly language program is
detailed in the following example.