BSV by Example - UCSD CSE [PDF]

BSV by Example The next-generation language for electronic system design

Rishiyur S. Nikhil and Kathy Czeck Revision: November 3, 2010 c 2010 Bluespec, Inc. All rights reserved. Copyright

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Contents Table of Contents

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1 Introduction

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1.1

Design activities where BSV is used . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1.2

Key ideas in BSV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1.2.1

Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1.2.2

Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1.3

Why BSV? Can’t we do all this with existing languages (like C++)? . . . . . . . . .

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1.4

About this book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2 Getting started with BSV 2.1

2.2

2.3

2.4

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A simple example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.1.1

Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.1.2

Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.1.3

(* synthesize *) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.1.4

Module definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.1.5

Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.1.6

System tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Building the design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.2.1

Bluespec Development Workstation (BDW) . . . . . . . . . . . . . . . . . . .

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2.2.2

Components of a BSV design . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.2.3

Overview of the BSV build process . . . . . . . . . . . . . . . . . . . . . . . .

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2.2.4

Create a project file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.2.5

Compile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Multiple modules in a single package . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2.3.1

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Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Multiple packages in a single design

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3 Tb.bsv", line 34, column 11: (P0040) Use of ’a’ without assignment

The variable on the right-hand side is now meaningless. Since a has not been initialized or assigned, it does not represent any combinational circuit, and so the expression a*a is meaningless.

5 5.1

Rules, registers, and fifos Defining and updating a register

Source directory: rulesregs/register Source listing: Appendix A.4.1 In this section we discuss the most basic state element, the register, and how to use registers to store values. We’ll also examine rules and how they are used to describe state transitions. This example defines a register containing int values; the name of the register is x: 38

package Tb; (* synthesize *) module mkTb (Empty); Reg#(int) x