Intel 210200-002 manual Processor Description

APPENDIX

INTRODUCTION

This benchmark report compares the capabilities of Intel's iAPX 88/10 microprocessor with those of the Motorola MC6809. The purpose of the report is to aid the user in his evaluation of the two processors, and to provide him with some of the information he will need in making a knowledgeable decision regarding which processor best satisfies the requirements of his applica- tion.

Because the requirements can vary so greatly from one system to the next, no one program can adequately display the capabilities of each processor. For this reason, ten programs have been chosen to demonstrate the performance of the iAPX 88/10 and MC6809 in several areas. The benchmark programs cover some of the basic tasks which are relevant to many of the ap- plications for which these two processors might be con- sidered. These ten programs demonstrate the proces- sors' capabilities in the areas of data manipulation, computation, and processor control. Each program was defined in such a way as to be relatively straight- forward, while still allowing the processors to use their instruction set efficiently in implementing the program.

The benchmark programs were used to evaluate the iAPX 88/10 and MC6809 on the basis of execution speed, memory usage, and ease of programming (num- ber of lines of code). These factors were considered because they are often the key requirements evaluated when a design decision is made. Execution speed is a direct measure of how fast a processor will complete a task. This can be the critical requirement for many real- time control or multi-user systems. Here, cost may not be the primary issue because a less expensive but slower system may be inadequate, regardless of the cost sav- ings. On the other hand, many systems do have critical cost requirements for which it may make sense to sacri- fice some execution speed in order to reduce costs. For a memory intensive system, the cost can be reduced signi- ficantly by using less memory, or cheaper, lower speed memory. For this reason, coding efficiency and memory access time were examined to help evaluate pricel performance tradeoffs. Another factor, the ease of pro- gramming, is becoming more and more important as the cost of memory decreases and the size of the typical microcomputer application rapidly grows. For many applications, software development costs have become greater than hardware development costs. This means that the total development costs of such a project can be substantially reduced by using the processor which ac- complishes the most in the least number of lines of code. To demonstrate performance in this area, the processors have also been evaluated on the basis of the number of lines of code required for each program which has been defmed as "ease of programming."

The benchmark programs in this report were written for the purpose of comparing the iAPX 88/10 and MC6809 microprocessors. They should be used only as a guide in

evaluating processor performance and are not an ab- solute measure of performance for all applications. The programs were written to perform the tasks in a clear and straightforward manner. They do not necessarily show an optimized implementation of the task. The benchmark programs do, however, provide relevant in- formation and a consistent comparison which may be useful to the designer in choosing the microprocessor which delivers the best solution to the requirements of his design.

PROCESSOR DESCRIPTION

A brief description of some of the key features of the iAPX 88 and MC6809 is included here and in Table 1.

Table 1. Architectural Features
Feature	iAPX88/10		MC6809
Memory Addressability	1 megabyte		64K bytes
General Registers
Number	8 or 8+4-		2 or 1··
Size (bits)	16 or 8,16·		8 or 16--
Instruction Sizes (bytes)	1,2,3,4,5,6		1,2,3,4,5
Operand Addressing Modes
Register	Yes		Yes
Immediate	Yes		Yes
Direct Address	Yes		Yes
Register Indirect	Yes		Yes
Indexed or Based	Yes		. Yes
Base +Indexed	Yes		No
Base + Displacement	Yes		No
Index + Displacement	Yes		Yes
Base + Indexed + Displacement	Yes		No
Indexed Indirect	No		Yes
Auto Increment/Decrement	Yes		Yes
Data Types
BCD Digits	Yes		Yes
ASCII Digits	Yes		No
Bytes	Yes		Yes
Words	Yes		Yes
Unsigned Integers	Yes		Yes
Signed Integers	Yes		Yes
General Double Operand
Operations
Reg with Reg to Reg	Yes		No
Reg with Mem to Reg	Yes		Yes
Reg with Mem to Mem	Yes		No
Reg with Imed to Reg	Yes		Yes
Mem with Imed to Mem	Yes		No
Mem with Mem to Mem	Yes		No
Interrupts .
NMI	Yes		Yes
Software Interrupts (#)	Yes (256)	-	Yes (3)
Fast External Interrupts (#)	No		Yes (1)
Multi-Vectored Interrupts (#)	Yes (256)		No

*The AX, BX, ex and DX registers can be used as four 16-bit registers, or as

eight 8-bit registers. With the index and pointer registers, this gives eight l6-bit registers, or eight 8-bit and four l6-bit registers.

··The A and B registers can be used as two B-bit registers or as one 16-bit

register.

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