[phylum]<CTamarin>Documentation>TamarinPresentation.slides!1

Tamarin

A Custom VLSI-Based Lisp Machine

Mark Ross

January 29, 1987

Presentation to Fuji-Xerox

Outline

Project Philosophy and Goals

System Configurations

Lisp Architecture

Project Status

Project Philosophy and Goals

AISBU needs an improved delivery vehicle for its Lisp system

· Performance must be improved

· Cost/performance must come down

· Size reduction would be helpful

Specialized architectures can improve Lisp performance

Project Philosophy and Goals (cont.)

Goals:

· Build an initial Lisp System Product

· Develop a Custom VLSI Processor

Provide specific support for Xerox Lisp

Improve performance over a 6085/1186 by 5X

Require a minimum of "glue" chips

· Create a Technology base for a series of VLSI Lisp machines

Path for future performance enhancements

Adaptable to many system configurations

System Configurations

1186 Softcard

PC-AT Softcard

Embedded system

Highly parallel architecture

SoftCard Concept

Example of 1186 SoftCard

Lisp Architecture - Mismatches

Premise: Specialized architectures can improve Lisp performance

Performance Mismatches:

· 16 bit word vs. full pointer

· Hardware stack

· Bottle-neck at instruction fetching

· Ineffecient Memory coupling

· Slow Virtual Memory Translation

Lisp Architecture - Requirements

Special Requirements of Lisp:

· Micro Conditionality

· Complex Function Call

· Tagged Pointers and Typed Data

· Dynamic Scoping

· Common Lisp

Multiple Values

Closures

Function Arguments

Lexical Scoping

Tamarin Specifics

Tamarin Addresses the previously mentioned issues with several key constructs (general and Lisp specific)

General:

· Hardware stacks and stack operations

· Instruction Buffer

· Unique Micro Code Implementation

· Close Memory Coupling (fast block transfers)

· Virtual Memory Map Cache (TLB)

Lisp Specific:

· 40 bit architecture (tag is built in to data word)

· Function Call Support

· Common Loops support

· Binding Stack support

Tamarin Feature Summary

The following is a partial list of the features present in the CMOS Tamarin processor

· Stack Frame structure :

6 frames X 40 words per frame

· Instruction Timing

3 stage pipeline

· Functional Units

Memory Controller

General ALU and Shifter

Multiplier/Divider

Micro-Code ROM

Register Control

Processor Block Diagram

A Word on RISC

Tamarin as a RISC machine

· Many instructions execute in one micro-instruction per opcode.

The ones that don't would require multiple cycle implementations on a standard RISC machine (e.g., Lisp Function Call)

· Many internal registers

· Simple Instructions and single addressing mode.

Tamarin is at least a FISC machine (Fast Instruction Set Computer)

Project Status

NMOS chip is back from fabrication

Testing of the processor is starting

There are signs of life from the Memory Interface chip

NMOS design effort was complete

Micro-code was completed

Much simulation was performed

CMOS chip development is continuing

A display controller board for the 6085 using the TI 34010 graphics controller is under development

Hardware Development Team

Alan Bell Project Leader, system arch.

Bob Krivacic Microcode & support software

Chuck Sainsbury Mask Layout & board layout

Celeste Chapman System Level engineering

Mark Ross Architecture and primary
CMOS designer

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