Tài liệu Ambit BuildGates Synthesis User Guide ppt

■ Command Reference for Ambit BuildGates Synthesis and Cadence PKS ■ Timing Analysis for Ambit BuildGates Synthesis and Cadence PKS ■ Test Synthesis for Ambit BuildGates Synthesis and Ca

Product Version 4.0.8

May 2001

Trademarks: Trademarks and service marks of Cadence Design Systems, Inc (Cadence) contained in this

document are attributed to Cadence with the appropriate symbol For queries regarding Cadence’s trademarks, contact the corporate legal department at the address shown above or call 1-800-862-4522.

All other trademarks are the property of their respective holders.

Restricted Print Permission: This publication is protected by copyright and any unauthorized use of this

publication may violate copyright, trademark, and other laws Except as specified in this permission statement, this publication may not be copied, reproduced, modified, published, uploaded, posted, transmitted, or

distributed in any way, without prior written permission from Cadence This statement grants you permission to print one (1) hard copy of this publication subject to the following conditions:

1 The publication may be used solely for personal, informational, and noncommercial purposes;

2 The publication may not be modified in any way;

3 Any copy of the publication or portion thereof must include all original copyright, trademark, and other proprietary notices and this permission statement; and

4 Cadence reserves the right to revoke this authorization at any time, and any such use shall be

discontinued immediately upon written notice from Cadence.

Disclaimer: Information in this publication is subject to change without notice and does not represent a

commitment on the part of Cadence The information contained herein is the proprietary and confidential information of Cadence or its licensors, and is supplied subject to, and may be used only by Cadence’s customer

in accordance with, a written agreement between Cadence and its customer Except as may be explicitly set forth in such agreement, Cadence does not make, and expressly disclaims, any representations or warranties

as to the completeness, accuracy or usefulness of the information contained in this document Cadence does not warrant that use of such information will not infringe any third party rights, nor does Cadence assume any liability for damages or costs of any kind that may result from use of such information.

Restricted Rights: Use, duplication, or disclosure by the Government is subject to restrictions as set forth in

FAR52.227-14 and DFAR252.227-7013 et seq or its successor.

Preface 9

About This Manual 9

Other Information Sources 9

Syntax Conventions 10

Text Command Syntax 10

About the Graphical User Interface 11

Using Menus 11

Using Forms 12

1 Introduction to Ambit BuildGates Synthesis 13

Separately Licensed Software Products 13

Low Power Synthesis 14

Physically Knowledgeable Synthesis 14

Datapath Synthesis 14

AC_Shell / DC_Shell Equivalencies 15

2 Getting Started 27

Invoking Ambit BuildGates Synthesis 27

Getting Help for Ambit BuildGates Synthesis 31

Exiting Ambit BuildGates Synthesis 32

Files Used in Ambit BuildGates Synthesis Software 33

Key Bindings and Mouse Operations 33

3 Using the GUI 37

Main Menu Functions 39

File Menu Options 40

Edit Menu Options 42

Contents

View Menu Options 44

Commands Menu Options 58

Reports Menu Options 61

Window Menu Options 69

Help Menu Options 71

The Main Tool Bar 73

The Browsers 74

The Module Browser 74

The Variable Browser 78

Work Area Tools 80

HDL and Tcl Editors 80

Constraints Tool 86

The Schematic Viewer and Symbol Files 90

Distributed Processing 92

Update Mode 93

The ac_shell Console 94

The Status Bar 95

4 Flow Procedures 97

Typical Synthesis Flow 97

Read the Libraries 99

Read the Design Data 102

Build a Generic Netlist 104

Set Constraints 106

Optimize the Design 108

Generate Reports 111

Save Final Netlist 113

5 Viewing the Schematic Design 115

How to Use the Schematic Viewer 116

Objects in the Schematic Database 119

Accessing Context-Sensitive Pop-Up Menus 120

Highlighting Path Between Pins 125

Viewing Bus Properties 126

The Schematic Tool Bar 128

The Module Title Bar 130

Searching for an Object 131

Grouping Instances 133

Dissolving Instances 134

Creating a Unique Module 135

Displaying Logic Cones 136

Extracting Logic Cones 137

Displaying Port Constraints 139

Printing a Schematic 140

6 Setting Constraints 141

Units in Constraints 141

Timing Constraints 141

Timing Analysis 142

Optimizing Before Place-and-Route 143

Runningdo_optimize Command 144

Top-Down Optimization 146

Bottom-Up Optimization 146

Deriving Constraints from Context 147

Time Budgeting 148

Preserving Module Contents 149

Uniquifying Instances 151

Collapsing Hierarchy 152

Incremental Optimization 154

Applying Timing Corrections 154

8 Optimizing with Logic Transforms 155

Introduction to Transforms 155

Logic Optimization Steps 156

Optimizing Generic Logic 157

Mapping and Unmapping of Generic Logic 158

Constraint-Driven Optimizing 159

Summary Listing of Transform Commands 161

9 Optimizing After Place-and-Route 163

Timing Analysis 163

Backannotating 164

A Script Showing the Backannotation of a Design 164

Reading SDF Data 166

Optimizing to Correct Late and Early Slack 166

10 Report Generation 169

Report Header 170

Timing Reports 170

Area Reports 171

Sample Area Report 172

Library Reports 173

Hierarchy Reports 174

Sample Hierarchy Report 175

Design Rule Violations Reports 176

Sample Design Rule Violations Report 177

VHDL Library Reports 178

Sample VHDL Library Report 179

End Point Slack and Path Histogram Reports 180

Fanin and Fanout Reports 181

Sample Fanin Report 182

Finite State Machine Reports 184

Sample FSM Report 185

Customizing Report Column Width 187

A Using Tcl within ac_shell and pks_shell 189

The Tcl Language 190

Procedures 190

Tcl Variables and Control Structures 191

Variables 191

Syntax 193

Tcl Commands 194

find Command 194

get_names Command 195

Abbreviating Commands 196

Searching for Commands 196

Accessing Environment Variables 196Returning Unix Command Values 196Error Handling 197

B

Quick Reference 199

This preface contains the following sections:

■ About This Manual on page 9

■ Other Information Sources on page 9

■ Syntax Conventions on page 10

■ About the Graphical User Interface on page 11

About This Manual

This manual describes the Ambit®BuildGates®synthesis software BuildGates synthesis can

be run both in command line mode and in graphical user interface (GUI) mode See GettingStarted on page 27 for an explanation on how to use both modes

Other Information Sources

For more information about Ambit BuildGates synthesis and other related products, you canconsult the sources listed here

■ Command Reference for Ambit BuildGates Synthesis and Cadence PKS

■ Timing Analysis for Ambit BuildGates Synthesis and Cadence PKS

■ Test Synthesis for Ambit BuildGates Synthesis and Cadence PKS

■ HDL Modeling for Ambit BuildGates Synthesis

■ Distributed Processing of Ambit BuildGates Synthesis

■ Synthesis Place-and-Route (SP&R) Flow Guide

■ Constraint Translator for Ambit BuildGates Synthesis and Cadence PKS

Depending on the product licenses your site has purchased, you could also have thesedocuments

■ Datapath Option of Ambit BuildGates Synthesis and Cadence PKS

■ Low Power Option of Ambit BuildGates Synthesis and Cadence PKS

BuildGates synthesis is often used with other Cadence® tools during various design flows.The following documents provide information about these tools and flows Availability of thesedocuments depends on the product licenses your site has purchased

■ Cadence Timing Library Format Reference

■ Cadence Pearl Timing Analyzer User Guide

■ Cadence General Constraint Format Reference

The following books are helpful references

■ IEEE 1364 Verilog HDL LRM

■ TCL Reference,Tcl and the Tk Toolkit, John K Ousterhout, Addison-Wesley

Publishing Company

Syntax Conventions

This section provides the Text Command Syntax used in this document

Text Command Syntax

The list below describes the syntax conventions used for the Ambit BuildGates synthesis textinterface commands

Important

Command names and arguments are case sensitive User-defined information is

case sensitive for Verilog designs and, depending on the value specified for the

global variable hdl_vhdl_case, may be case sensitive as well

These keywords represent command or option names

for which you must substitute a name or a value

[ ] Brackets denote optional arguments When used with OR-bars,

they enclose a list of choices from which you can choose one

{ } Braces are used to indicate that a choice is required from the list

of arguments separated by OR-bars You must choose one fromthe list

{ argument1 | argument2 | argument3 }

braces must be typed in literally

Three dots ( ) indicate that you can repeat the previous

argument If the three dots are used with brackets (that is,[argument] ), you can specify zero or more arguments Ifthe three dots are used without brackets (argument ), youmust specify at least one argument, but can specify more

About the Graphical User Interface

This section describes the conventions used for the BuildGates synthesis graphical userinterface (GUI) commands and describes how to use the menus and forms in the BuildGatessynthesis software

CommandName -> A command name with a right arrow displays an additional menu

with more commands Multiple layers of menus and commandsare presented in what are called command sequences, forexample:File – Import – LEF In this example, you go to the Filemenu, then the Import submenu, and, finally, the LEF command

Using Forms

capability When you select the browse button, a list of choicesappears

Cancel TheCancel button cancels the command and closes the form

Defaults TheDefaults button displays default values for options on the

Capable of running in both command line mode and in graphical user interface (GUI) mode,the BuildGates synthesis tool delivers dramatic performance and productivity benefits overconventional synthesis tools The key features of the Ambit BuildGates synthesis tool aredescribed in the following paragraphs.

At the heart of the Ambit BuildGates synthesis tool is a signoff-quality, fast, full-chip timingengine that enables high-capacity and high-performance chip-level synthesis Fast andflexible, BuildGates synthesis supports a wide variety of design styles such as multiple clocks,including both edge triggered and level sensitive with cycle stealing

BuildGates synthesis has a high capacity database that allows synthesis of more of thedesign at once Its fast runtime assures rapid turnaround, making chip-level synthesis

practical In addition, high-capacity enables productivity gains by eliminating the need forexcessive resources and time required for elaborate bottom-up script development

BuildGates synthesis also offers automatic time budgeting, integration with physical designtools, VHDL and Verilog support, support of both reads and writes of netlist EDIF 2.0, Tclcommand line interface for shell level control, transforms for performing focused

optimizations, schematic and textual report capabilities, and integrated DFT analysis andscan insertion

Separately Licensed Software Products

Cadence® low power synthesis, Cadence physically knowledgeable synthesis (PKS), andCadence datapath synthesis option are companion products to the basic Ambit BuildGatessynthesis software and require separate licenses For details on these products, please

contact your Cadence marketing representative If you are a licensed user, the appropriatesoftware and documentation are included in your installation package.

Low Power Synthesis

The low power module provides both power analysis and power optimization capabilities.Power analysis estimates the power consuming modules in your design at the gate-levelthrough each phase of the design cycle until you have met your power specifications Thepower optimizer synthesizes a minimum power netlist that meets your specified timingconstraints, optimizing design power consumption at the register-transfer level (RTL)

Licensed users can refer to theLow Power Option of Ambit BuildGates Synthesis andCadence PKS for details

Physically Knowledgeable Synthesis

Cadence physically knowledgeable synthesis (PKS) performs placement-driven timing byadding a physical model of the netlist to the timing and interconnect models that currentlyexist in the Ambit BuildGates synthesis tool The physical model allows for timing estimations

to take place during the optimization process, virtually eliminating the need for third-partyplacement tools

Placement information is read into PKS using a PDEF file, which includes thex,y location

of every cell PKS uses highly accurate Steiner routes to estimate interconnect, resulting incloser correlation between the timing in BuildGates synthesis and the timing that results afterrunning a place-and-route tool

Licensed users can refer to thePKS User Guide for details

Licensed users can refer to theDatapath Option of Ambit BuildGates Synthesis and

AC_Shell / DC_Shell Equivalencies

The table below shows thedc_shell commands and theirac_shell equivalents

Table 1-1 AC_Shell and DC_Shell Command Equivalencies (Sheet 1 of 11)

compile -incremental do_xform_optimize_slack

compile_fix_multiple_port_

net

do_xform_fix_multiport_netsset_global fix_multiport_nets

Table 1-1 AC_Shell and DC_Shell Command Equivalencies (Sheet 3 of 11)

remove_attribute remove_assertions

Table 1-1 AC_Shell and DC_Shell Command Equivalencies (Sheet 5 of 11)

Table 1-1 AC_Shell and DC_Shell Command Equivalencies (Sheet 6 of 11)

set_clock_propagation -ideal |propagated

Table 1-1 AC_Shell and DC_Shell Command Equivalencies (Sheet 7 of 11)

set_dont_touch set_cell_property dont_modify true

and pragmasset_fsm_encoding_style Verilog source code pragmas, VHDL attributes

set_load -pin_load set_port_capacitance

Table 1-1 AC_Shell and DC_Shell Command Equivalencies (Sheet 9 of 11)

set_multicycle_path N -hold set_cycle_addition N -early

Getting Started

Invoking Ambit BuildGates Synthesis

The Ambit BuildGates synthesis software is installed in the following directory:

The command line options for invoking the Ambit BuildGates synthesis software are listed inTable 2-1 and described in more detail in the Command Reference for Ambit BuildGatesSynthesis and Cadence PKS,ac_shellcommand Unless otherwise specified, the optionsare valid for both command line and GUI mode Multiple options can be used in a singlecommand

Table 2-1 Ambit BuildGates Synthesis Command Line Options

-cdsdocd {on | off} Enable or disable the browser-based documentation

delivery system forac_shell help When set toon,the full documentation set is available from theHelpbutton in the GUI When set tooff, only the syntax isdisplayed at the command line

Whenac_shellis invoked with the-guioption, thedefault is on such that the online, browser-baseddocumentation is enabled

Whenac_shell is invoked without the-gui option,the default isoff and only syntax help is available atthe command-line

-cmdfile filename.cmd Record in a file, all executed commands in the

session The default file name isac_shell.cmd.-colormap filename Run Ambit BuildGates synthesis software using the

specified file Valid only in GUI mode

the Datapath option A separate license must bepurchased for the Datapath option

-display machine_name:0 Set the configuration to display Ambit BuildGates

synthesis software to the specified machine Validonly in GUI mode

[-f] filename.tcl Run Ambit BuildGates synthesis software using the

specified Tcl file You can specify thefilename.tclwithout typing the optional-f

only in GUI mode

Table 2-1 Ambit BuildGates Synthesis Command Line Options, continued

-geometrywidth X

Set the initial size and position of the GUI main screenwindow Wherewidth andheight are in pixels.Andxoff and yoff are the number of pixels fromthe corner; a negative value is measured from thebottom or right corners, and a positive value ismeasured from the top or left corners No spaces areallowed between the values

For example: -geometry 800x400+10-30 meanscreate a window 800 by 400 pixels with its left edgeoffset 10 pixels from the left edge of the screen and itsbottom edge offset 30 pixels from the bottom of thescreen

Valid only in GUI mode

GUI interface

software

depending on the platform and configuration

limit for the machine on which the software will run.Does not run the software

-logfile filename.log Record in a file, all executed commands and

ac_shell console messages in the session Thedefault file name isac_shell.log

$ambit_path/.acshrc

license; if this fails, run with PKS license Only valid if

a separate license has been purchased for PKS

standard license Only valid if a separate license hasbeen purchased for PKS

Table 2-1 Ambit BuildGates Synthesis Command Line Options, continued

-pks Run the Ambit BuildGates synthesis application with

the physically knowledgeable synthesis option Aseparate license must be purchased for PKS

the low power option A separate license must bepurchased for the low power option

-set variable=value Initialize a Tcl variable to the specified value

name of the Ambit BuildGates synthesis executable

Table 2-1 Ambit BuildGates Synthesis Command Line Options, continued

Getting Help for Ambit BuildGates Synthesis

Help is available in two different modes: command-line syntax help and online,

browser-based documentation delivery By default, the command-line syntax help is available

in both command-line and GUI mode

The browser-based help is available only whenac_shell is invoked with the-gui option.This online help provides the full Ambit BuildGates synthesis documentation set and isaccessed via theHelp button on main menu line in the GUI, as shown in Figure 3-1 onpage 37 The functions of the Help button are defined in Table 3-25 on page 71 You candisable the browser-based help with the the-cdsdocd option, as defined in Table 2-1

To use the command-line syntax help, type the following on theac_shell console line:

ac_shell[1]> help command_name

If you are uncertain as to the name of the command you are seeking, enter a partial commandname For example, the following will display applicable commands

ac_shell[2]> help do_opt

Exiting Ambit BuildGates Synthesis

To quit the command line version of Ambit BuildGates synthesis software, typeexit at theac_shell prompt and pressReturn

ac_shell[n]>exit

To quit the GUI version of Ambit BuildGates synthesis software, do one of the following:

■ SelectMain Menu – File – Exit; click Ok when the exit confirmation dialog is displayed

■ Press the Control-x key sequence; clickOk when the exit confirmation dialog is

Files Used in Ambit BuildGates Synthesis Software

The default file extensions used in Ambit BuildGates synthesis software are shown in thetable below

Key Bindings and Mouse Operations

Table 2-3 lists the key sequences and mouse operations that can be used in the HDL/Tcleditors andac_shellconsole ThePage_Up, Page_Down, Prior, and Next keys refer tothe keys to the left of the numeric keypad; thePgUp and PgDn keys on the numeric keypad

do not operate in the editors orac_shell console

Table 2-2 Default File Extensions

File Name Extensions Description

tcl_menu.cmds User-created commands on the Tcl menu

ambit.state Stores state information, user preferences, window

positions, and so on

Table 2-3 Key Sequences and Mouse Operations

Key/Mouse

Description

Left Arrow, Control-b Move back one character

Right Arrow, Control-f Move forward one character

Up Arrow, Control-p Move insertion cursor up one

line

Display previous history event

Down Arrow, Control-n Move insertion cursor down

one line

Display next history event

Next, Page_Down Scroll down one page

Home, Control-a Move insertion cursor to the beginning of the line

End, Control-e Move the insertion cursor to the end of the line

word) or file completion (onany other word)

line)

Issue a command

Delete Delete highlighted character(s) or delete character in front of

the insertion cursor

BackSpace, Control-h Delete highlighted character(s) or delete character to the left

of the insertion cursor

Control-d Delete the character to the right of the insertion cursor

Control-k Delete from the insertion cursor to the end of the line

losing current command lineinput

Control-m Toggle between the standard split-screen and the

whole-screen display to minimize or maximize the window inwhich the cursor resides

Table 2-3 Key Sequences and Mouse Operations, continued

Key/Mouse

Description

Control-u No function Clear the command line.Meta-d Delete the word to the right of the insertion cursor.

Meta-BackSpace Delete the word to the left of the insertion cursor

Click middle mouse button,

Insert

Paste the highlighted text where the cursor is located

Copy, Control-c Copy functions as in console

Control-c: no function

Copy the highlighted text tothe clipboard

Cut, Control-x Cut functions as in console

andControl-x exits AmbitBuildGates synthesissoftware

Copy the highlighted text tothe clipboard and delete thetext

Paste, Control-v Paste functions as in console

Control-v: no function

Paste the contents of theclipboard onto the commandline

Table 2-3 Key Sequences and Mouse Operations, continued

Key/Mouse

Description

Using the GUI

This chapter describes the principle screens, windows, and menus of the Ambit BuildGatessynthesis graphical user interface (GUI) The main screen is the first screen you see whenyou start the tool in the GUI mode (refer to Invoking Ambit BuildGates Synthesis on page 27for startup options) The functions of main screen are called out in Figure 3-1 and

Update

mode

Main

PKS and the low power option are additions to the BuildGates synthesis product Ifyou have the licenses for these products, the tabs are displayed on the work areatool bar and the functionality is available in your application Power and PKS are

documented in the Low Power Option of Ambit BuildGates Synthesis and

Cadence PKS and PKS User Guide, respectively

Figure 3-2 Main Screen Function Flow

The main menu, browsers, and work area tools functions contain options and commands thathaveac_shell command line equivilalents For a cross-reference between these

commands andac_shell command line commands, refer to Appendix B, “Quick

Reference”

Important

This chapter is intended as a navigational tool for BuildGates synthesis, not a

complete reference guide; menu options are listed but not defined in detail Refer totheCommand Reference for Ambit BuildGates Synthesis and Cadence PKSfor details on each command and its options

Status Bar

Main Screen

Tools ac_shell Console Main

Main Menu Functions

The main menu functions are diagrammed below

Each of these functions has a menu associated with it and is explained in the followingsections

For a cross-reference between the main menu commands andac_shell command linecommands, refer to Appendix B, “Quick Reference”

File Menu Options

The file menu functions are diagrammed below and Table 3-1 defines the options

Table 3-1 File Menu Options

Option Definition

New Clear the current database information so that a new design

database can be loaded After selectingNew, use View–Open

to specify the new database file

Open Open a database file and load the design data for synthesis

Figure 3-3 provides a sample Open File dialog box (Samefunction as the Open icon on the Tool Bar; see “The Main ToolBar” on page 73.)

Specify the type of file with the buttons on the right, and specifythe file location in the dialog box on the left

Save Save the database to an ADB, Verilog, or VHDL file (Same

function as the Save icon on the Tool Bar; see “The Main ToolBar” on page 73.)

Save Preferences Save the preferences changed on the General Preferences and

Schematic Preferences option windows; see “General

Preferences

Console Log

Setup File