Z8F64220100ZDA Zilog, Z8F64220100ZDA Datasheet - Page 251
Manufacturer Part Number
ADAPTER ICE Z8 ENCORE 64K 64LQFP
Specifications of Z8F64220100ZDA
For Use With/related Products
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Assembly Language Programming Introduction
CPU Instruction Set
The eZ8 CPU assembly language provides a means for writing an application program
without having to be concerned with 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
statements. Each statement can contain labels, operations, operands and comments.
Labels can be 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-ops, are not translated into a machine
instruction. Rather, the pseudo-ops are interpreted as directives that control or assist the
The source program is processed (assembled) by the assembler to obtain a machine
language 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.
Assembly Language Source Program Example
LD R4, R7
LD 234H, #%01
; Everything after the semicolon is a comment.
; A label called “START”. The first instruction (
; example causes program execution to jump to the point within the
; program where the
; A Load (LD) instruction with two operands. The first operand,
; Working Register R4, is the destination. The second operand,
; Working Register R7, is the source. The contents of R7 is
; written into R4.
; Another Load (LD) instruction with two operands.
; The first operand, Extended Mode Register Address
; identifies the destination. The second operand, Immediate Data
; Register at address
, is the source. The value
Z8 Encore! XP
is written into the
CPU Instruction Set
) in this