Zilog Z16F2810 - Manual (Page 18)

Architectural Overview UM018809-0611
2
ZNEO
®
CPU Core
User Manual
Program Control
ZNEO CPU is controlled by a program stored in memory as object code. An object code is
a sequence of numerical opcode and operand bytes. An opcode specifies an instruction to
perform while operands specify the data addresses to be operated upon. Numerical object
code is rarely used to write programs. Instead, programs is written in a symbolic assembly
language using easily remembered (mnemonic) instructions. A program called an assem-
bler translates assembly language into object code.
This user manual provides details about using ZNEO CPU instructions in both object code
and assembly language. Those interested in writing assembly language can skip object
code details handled by the assembler.
Programmers using high-level languages like ‘C’ require this manual while writing opti-
mized routines in assembly language. Otherwise, the compiler or interpreter’s documenta-
tion should describe processor-specific details affecting program operation.
Processor Block Diagram
The ZNEO CPU consists of following two major functional blocks:
•
Fetch Unit
•
Execution Unit

The Fetch and Execution units access memory through a bus arbiter. The Execution Unit
is subdivided into the Instruction State Machine, Program Counter, Arithmetic Logic Unit
(ALU), and ALU registers.
Figure 1 on page 3 displays the ZNEO CPU architecture.