Intel i960 User Manual

i960 Processor Compiler
User's Guide

Order Number: 651230-002

Revision Revision History Date

-001 Original Issue. 02/96

-002 Revised for release 5.1 01/97

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Copyright  1996, 1997. Intel Corporation. All rights reserved.

Contents

Chapter 1 The CTOOLS Compilation System

Features........................................................................1-1

Compatibility and Conformance to Standards....................1-2

About this Manual..............................................................1-4

Audience Description.....................................................1-6

Licensing and Copyrights..............................................1-6

UNIX and Windows Conventions...................................1-6

Customer Service...............................................................1-7

Where Do You Go From Here?..........................................1-7

Chapter 2 gcc960 Compiler Driver

Controlling the Compilation System with gcc960 ...............2-1

Invoking the Compiler with gcc960................................2-2

gcc960 Sample Command Lines...................................2-3

gcc960 Linker Options...................................................2-5

gcc960 and Predefined Macros.....................................2-6

gcc960 and File Use ..........................................................2-8

Input Files......................................................................2-8

Include Files..................................................................2-9

Output Files...................................................................2-9

.GLD Files..........................................................................2-11

gcc960 Options..................................................................2-13

Option Arguments and Syntax...........................................2-15

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i960 Processor Compiler User's Guide

Chapter 3 ic960 Compiler Driver

Controlling the Compilation System with ic960...................3-1

Invoking the Compiler with ic960...................................3-2

ic960 Sample Command Lines......................................3-3

ic960 Linker Options......................................................3-4

ic960 and Predefined Macros........................................3-6

ic960 and Environment Variables..................................3-8

ic960 and File Use .............................................................3-11

Input Files......................................................................3-11

Include Files ..................................................................3-11

Temporary Files .............................................................3-12

Output Files...................................................................3-12

ic960 Options.....................................................................3-15

Option Arguments and Syntax ...........................................3-17

Chapter 4 Program-wide Analysis and Optimization

Introduction ........................................................................4-1

Individual and Program-wide Optimizations...................4-1

About Profiling...............................................................4-2

Creating Program-wide and Module-local Optimizations ....4-2

Specifying the Program Database Directory..................4-2

Compiling for Program-wide Optimization with the fdb

Option............................................................................4-3

Global Decision Making and Optimization Using the

gcdm Option..................................................................4-3

Selecting Modules for Optimization with Substitution

Specifications ................................................................4-4

iv

Contents

Profiling Your Program.......................................................4-5

Compiling for Profile Instrumentation with -fprof............4-5

Collecting a Profile.........................................................4-5

Building Self-contained Profiles with gmpf960...............4-6

Using Profiles During Global Decision Making and

Optimization with -gcdm,iprof ........................................4-7

Obtaining Program Coverage Analysis with gcov960 ....4-7

Using make To Perform Program-wide Optimizations........4-7

Adapting Makefiles for Program-wide Optimization.......4-8

Using Makefiles with Program-wide Optimizations for

Common Development Tasks .......................................4-10

Runtime Support for Profile Collection...............................4-15

Profile Initialization.........................................................4-15

Chapter 5 Profile Data Merging and Data Format (gmpf960)

Merging Profile Data ..........................................................5-1

gmpf960 Invocation............................................................5-2

Profile Format Specification ...............................................5-4

Profile Data Structures ..................................................5-4

default.pf File Format.....................................................5-4

Creating a Runtime Report with gmpf960..........................5-6

Chapter 6 gcdm Decision Maker Option

gcdm Option Syntax...........................................................6-1

gcdm Option Arguments ....................................................6-2

Substitution Controls .....................................................6-2

Whole-program Optimization Option (Category 1).........6-3

Module-local Optimization Options (Category 2)...........6-3

Miscellaneous Substitution Options (Category 3)..........6-5

External Reference Controls .........................................6-7

v

i960 Processor Compiler User's Guide

Inline Level Control........................................................6-7

Input Profile Control.......................................................6-8

Fast Memory Controls ................................................... 6-8

Dryrun Control ...............................................................6-9

Report Controls .............................................................6-9

Module-set Specification....................................................6-13

Chapter 7 Language Implementation

Data Representation..........................................................7-1

Scalars...........................................................................7-1

Aggregates....................................................................7-4

Other Type Keywords....................................................7-14

Calling Conventions ...........................................................7-14

Definitions......................................................................7-15

Parameter Assignment to Registers..............................7-17

Argument Blocks ...........................................................7-17

Return Values................................................................7-18

Compiler Implementation...............................................7-18

Object Module Section Use................................................7-19

Pragmas.............................................................................7-20

#pragma align [for gcc960 driver]..................................7-20

#pragma align [for ic960, or for gcc960 with

ic960 option]..................................................................7-22

#pragma cave................................................................7-26

#pragma compress........................................................ 7-30

#pragma i960_align [for gcc960 and ic960]...................7-31

#pragma inline...............................................................7-31

#pragma interrupt..........................................................7-32

#pragma isr....................................................................7-34

vi

Contents

#pragma optimize..........................................................7-34

#pragma pack................................................................7-35

#pragma pure................................................................7-37

#pragma section............................................................7-38

#pragma system............................................................7-38

Language Extensions ........................................................7-39

Statements and Declarations Inside of Expressions .....7-40

Naming an Expression’s Type.......................................7-40

Referring to a Type with typeof......................................7-41

Generalized Lvalues......................................................7-42

Conditional Expressions with Omitted Middle

Operands.......................................................................7-44

Arrays of Length Zero....................................................7-44

Non-lvalue Arrays Can Have Subscripts........................7-45

Arithmetic on Pointers to void and Pointers to

Functions.......................................................................7-45

Non-constant Initializers................................................7-46

Constructor Expressions ...............................................7-46

Declaring Attributes of Functions...................................7-47

Inquiring about Alignment..............................................7-48

Inline Functions Are as Fast as Macros.........................7-48

Controlling Names Used in Assembly Code..................7-50

Specifying Registers for Local Variables.......................7-51

Alternate Keywords .......................................................7-51

Inline Assembly Language.................................................7-52

Introduction....................................................................7-52

Resource Usage............................................................7-52

asm Statements ............................................................7-53

asm Functions...............................................................7-70

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i960 Processor Compiler User's Guide

Chapter 8 gcc960/ic960 Compatibility

char and short Parameters............................................8-1

enum Variable Byte Count.............................................8-1

char Types.....................................................................8-2

Identifying Architectures ................................................8-2

#pragma align................................................................8-3

mic3.0-compat Option....................................................8-3

mic2.0-compat Option....................................................8-3

Chapter 9 Position Independence and Reentrancy

Position-independent Code and Data ................................9-1

Position-independent Data............................................9-1

Position-independent Code...........................................9-2

Example: Position-independent ROM Code.................9-3

Guidelines for Writing Relocatable Programs................9-5

Reentrant Functions...........................................................9-6

Designing Reentrant Functions .....................................9-6

Chapter 10 Initializing the Execution Environment

Startup Code......................................................................10-1

RAM-based Initialization................................................10-4

ROM-based Initialization................................................10-4

Linker Configuration Files...................................................10-5

RAM-based Configuration File.......................................10-6

ROM-based Configuration File ......................................10-6

Chapter 11 Optimization

viii

Optimization Categories and Mechanisms.........................11-1

Constants and Expression Evaluation................................11-3

Common Sub-expression Elimination............................11-3

Constant Expression Evaluation (Constant Folding) ..... 11-4

Dead-code Elimination...................................................11-5

Identity Collapsing.........................................................11-5

Constant Propagation....................................................11-6

Contents

Calls, Jumps, and Branches ..............................................11-9

Branch Optimizations ....................................................11-9

Branch Prediction..........................................................11-10

Identification of Leaf Functions......................................11-11

Inline Function Expansion .............................................11-11

Tail-call Elimination........................................................11-12

Loop Optimizations ............................................................11-14

Movement of Loop-invariant Code ................................11-14

Induction Variable Elimination.......................................11-14

Loop Unrolling...............................................................11-15

Memory Optimizations........................................................11-15

Global Alias Analysis.....................................................11-15

Variable Shadowing ......................................................11-16

Register Use ......................................................................11-16

Local Variable Promotion ..............................................11-17

Register Management...................................................11-17

Register Spilling.............................................................11-17

Instruction Selection and Sequencing................................11-18

Code Compression........................................................11-18

Code Scheduling...........................................................11-18

Specialized-instruction Selection...................................11-20

Program-level Optimization................................................11-20

Inter-module Function Inlining.......................................11-20

Superblock Formation ...................................................11-21

Profile-based Branch-prediction Bit Setting...................11-22

Chapter 12 Caveats

Aliasing Assumptions.........................................................12-1

Alignment Assumptions......................................................12-3

Volatile Objects..................................................................12-4

Known Problems Using the Compiler.................................12-6

Type Promotion.............................................................12-6

Prototype Scope............................................................12-6

ix

i960 Processor Compiler User's Guide

longjmp and Volatile Data..............................................12-7

Incorrect debug information generated for arrays with

unspecified bounds........................................................12-7

C Version Incompatibilities.................................................12-8

String Constants Read-only...........................................12-8

No Macro Argument Substitution in Strings...................12-8

External Variables and Functions in Blocks ...................12-8

Combining long with typedef Names .............................12-9

Using typedef Names in Function Parameters .............. 12-9

Whitespace in Compound Assignment Operators.........12-9

Flagging Unterminated Character Constants.................12-10

Disguised varargs or stdarg Routines ............................12-10

Troubleshooting .................................................................12-10

Undefined References...................................................12-10

C Interrupt Service Routine Failures ..............................12-11

Preventing Structure Padding........................................12-12

Breakpoints Inside Interrupt Handlers ........................... 12-15

Chapter 13 Messages

Messages on the Standard Error Device.......................13-2

Messages in the Listing File ..........................................13-3

Index
Figures

7-1 Natural Alignment......................................................7-8

7-2 User-constrained Alignment ......................................7-9

7-3 Optimal Natural Alignment of std_struct.................... 7-12

7-4 Backward-compatible Natural Alignment of

std_struct...................................................................7-13

7-5 #pragma noalign Alignment of std_struct..................7-13

7-6 #pragma align Alignment of std_struct......................7-14

9-1 Memory for Hypothetical Position-independent

Application.................................................................9-4

11-1 Superblock Formation Process..................................11-21

x

Contents

Tables

1-1 Compiler Limits..........................................................1-3

1-2 Chapter Descriptions.................................................1-4

2-1 Linker Options Accepted by gcc960..........................2-6

2-2 Intermediate Inputs and Outputs...............................2-10

2-3 gcc960 Option Summary...........................................2-15

2-4 Mcore Supported Architectures.................................2-41

3-1 Linker Options Accepted by ic960.............................3-5

3-2 Intermediate Inputs and Outputs...............................3-13

3-3 ic960 Option Summary..............................................3-17

3-4 Gcore Supported Architecures..................................3-37

3-5 Stop-after Option Phases and Output.......................3-59

6-1 gcdm Option Arguments............................................6-1

7-1 Scalar Data Types.....................................................7-2

7-2 Example Offset Values..............................................7-36

7-3 Return Value Class Matching....................................7-75

7-4 Argument Category to Parameter Class Matching

and Coercion.............................................................7-75

7-5 C Data Types and asm Classes................................7-78

8-1 Architecture Macros and Compatibility......................8-2

level

11-1 Optimizations and O

Settings ............................11-2

11-2 Examples of Constant Expression Evaluation...........11-4

11-3 Examples of Identity Collapsing................................11-6

xi

The CTOOLS Compilation System

This manual provides operating instructions and other information on the
CTOOLS compilation system. This system consists of a compiler and two
drivers that provide the user interface to the compiler, gcc960 and ic960.
These two interface drivers allow backward compatibility with software
developed using GNU/960 and CTOOLS960 respectively.

Features

The compiler lets you use the following features to develop applications:

• Use of either the gcc960 or ic960 compiler driver to invoke and

control translation and linking.

• Creation of a run-time performance profile of your application.

Optimizations based on this profile include inter-module optimizations
and preferential use of fast memory regions for variables that are
heavily used. For an overview of the program-wide optimization
process, including profile-driven optimization, see Chapter 4. For
descriptions of other optimizations, refer to Chapter 11.

• Calling

text, or including in-line assembly language in your C program.

• Stopping the compilation process to examine intermediate results after

syntax checking, preprocessing, compilation, assembly, or incremental
linking. (See Chapters 2 and 3.)

• Using a single command to translate and link modules into a complete

ROM-able or executable program. (See Chapters 2 and 3.)

functions written in i960 processor assembly language source

1

1-1

1

i960 Processor Compiler User's Guide

• Using the CAVE pragma to compress functions, thus reducing code

size. During program execution, these functions are decompressed
when called. For more information on the CAVE and other pragmas,
see Chapter 7.

• Creating blended code with the new

options. With these options, you can generate code that is compatible
with multiple i960 processor types. For more information, see
Chapters 2 and 3.

-mcore0-3 and -Gcore0-3

Compatibility and Conformance to Standards

The compiler runs on a UNIX* or a Windows* 95/NT* host system and
generates object code for any i960 commercial processor. The translation
and code generation phases use the instruction set for the i960 processor
that you specify.

The compiler's implementation of C conforms to the ANSI standard for
the C language (X3.159-1989). One exception is static pointer
initialization in applications using position-independent code or data
(described in Chapter 9). Additionally, the compiler allows use of in-line
assembly language in the C source text.

1-2

The ANSI standard specifies that a conforming implementation of a C
compiler must meet minimum requirements for certain translation limits.
In all cases, the compiler exceeds ANSI limits. Table 1-1 lists the tested
levels for each translation limit and compares them to ANSI minimum
requirements. Available memory determines actual limits in a host
system.

The CTOOLS Compilation System

Tested

Minimum

128

32

32

64

128

128

33

1024

4096

128

4096

4096

65535

32

1024

512

512

64

2048

128

Table 1-1 Compiler Limits

Limit

Control structure nesting levels 15
Conditional compilation nesting levels 6
Declarator modifiers 12
Declaration parenthesis nesting levels 31
Parenthesis nesting levels 32
Significant characters for internal identifier 31
Name length for external identifier 6
Identifiers in a single block 127
Macros simultaneously defined 1024
Parameters per function call 31
Characters in a logical line 509
Characters in a string 509
Bytes in an object 32767
Include file nesting levels 8
Case labels in a switch 257
Members in one structure or union 127
Enumeration constants in one enumeration 127
Structure nesting levels 15
External identifiers per file 511
Parameters per macro 31

1

ANSI
Minimum

1-3

1

i960 Processor Compiler User's Guide

About this Manual

This manual contains the following chapters:

Table 1-2 Chapter Descriptions

Chapter
Number Title Description

1. The CTOOLS
Compilation
System

2. gcc960 Compiler
Driver

3. ic960 Compiler
Driver

4. Program-wide
Analysis and
Optimization

5. Profile Data
Merging and
Data Format
(gmpf960)

6. gcdm Decision
Maker Option

Introduces the compiler and provides
information on using this manual.

Teaches you how to use the gcc960
command-line interface and provides a
complete list of command line options.

Teaches you how to use the ic960 command­line interface and provides a complete list of
command line options.

Tells you how to use some of CTOOLS most
powerful optimization features:

• individual module optimizations

• program-wide optimizations

• run-time profiling

Explains how to use gmpf960 to merge the
execution profile data you collected in
Chapter 4. You also learn how to use
gmpf960 to create a report that shows how
many times each basic block was “hit” or run
during program execution.

Describes the gcdm option, which invokes the
gcdm960 global optimization decision maker
during the link process. The decision maker
then invokes the compiler and linker as
necessary to perform program-wide
optimizations.

1-4

continued

☛

The CTOOLS Compilation System

Table 1-2 Chapter Descriptions (continued)

Chapter
Number Title Description

7. Language
Implementation

Describes data representation, register use,
object file format use, and pragmas for
modifying code generation.

1

8. gcc960 / ic960
Compatibility

9. Position
Independence
and Reentrancy

10. Initializing the
Execution
Environment

11. Optimization Describes the different ways in which the

12. Caveats This chapter provides useful programming

Describes the incompatibilities between ic960
and gcc960.

Provides information on writing i960
processor applications that require position­independent or reentrant programs.

Describes the initialization process for the
i960 processor execution environment,
including the startup assembly-language
routine, configuration files, and associated
options.

compiler can optimize your program and
explains ways to control optimization.

tips on:

• Aliasing assumptions

• Alignment assumptions

• Volatile object

• Known problems

• C version incompatibilities

• Troubleshooting

13. Messages Describes the diagnostic messages that the

compiler produces.

1-5

1

i960 Processor Compiler User's Guide

Audience Description

This manual assumes that you are familiar with the i960 processor
architecture, C and assembly language programming, and your host
computer's operating system.

Licensing and Copyrights

Refer to the i960 Software Tools License Guide for licensing and copyright
statements.

UNIX and Windows Conventions

This manual tells you how to use the compiler in both UNIX and Windows
95/NT systems. This manual uses the following conventions:

• Command-lines appear without a preceding prompt.

• Paths use the UNIX forward slash (

backslash (

• Command-line option examples use the UNIX dash (

than the Windows forward slash (

• Environment variables are referenced using the UNIX dollar-sign

(e.g.,

\) for pathnames.

$I960BASE), not the Windows % character.

/) rather than the Windows

-) prefix rather

/) prefix.

1-6

NOTE. In UNIX, only the dash (-) is accepted as a prefix for a
command-line option. In Windows, both the (
as a prefix for a command-line option.

-) and the (/) are accepted

The CTOOLS Compilation System

Customer Service

If you need service or assistance with CTOOLS, see your Getting Started
with the i960 Processor Development Tools manual.

Where Do You Go From Here?

If you installed the CTOOLS GNU interface, go to Chapter 2 for
information on using the gcc960 compiler driver. If you installed the
CTOOLS/960 interface, go to Chapter 3 for information on using the
ic960 compiler driver. Once you are familiar with the compiler driver
interface, you are ready to read Chapters 4 through 6, where you learn
how to use some of the more advanced features of the compilation system,
including whole program optimizations, profiling, and using the gcdm
global decision maker program.

1

1-7

gcc960 Compiler Driver

This chapter describes how to use the gcc960 driver program to control the
compilation system. Topics include:

• running the compilation system

• sample command lines

• predefined macros

• command line options and their modifiers

Controlling the Compilation System with gcc960

gcc960-style translation and linking requires use of the gcc960 driver,
preprocessor, compiler, assembler, and linker.

2

The gcc960 compiler driver (
controls the preprocessor (
the compiler (
invoke the assembler, linker, and gcdm960 optimization decision maker.

Command-line options and environment variables allow you to control the
compilation.

gcc960 controls preprocessing, compilation, assembly and linking.

• Filenames ending in

compiled.

• Filenames ending in

compiled.

• Compiler output files plus any input files with names ending in

assembled.

• Input files with names ending in

then assembled. (UNIX only.)

cc1.exe in Windows, cc1.960 on Unix). It can also

gcc960.exe in Windows, gcc960 on Unix)

cpp.exe in Windows, cpp.960 on Unix) and

.c are taken as C source to be preprocessed and

.i are taken as preprocessor output to be

.s are

.S (uppercase) are preprocessed and

2-1

2

i960 Processor Compiler User's Guide

• The resulting object files, plus any other input files, are passed to the

linker to produce an executable.

• Program-wide and profile-directed optimizations can be performed

during the link step. For an overview of this capability, see Chapter 4.

Invoking the Compiler with gcc960

The gcc960 command-line syntax is:

gcc960 [-

option

]... [

path/]filename

... [@

response-file

]

gcc960

option

is the compiler driver executable filename.
is a compiler option. Case is significant in

options and their arguments. Multiple single­character options cannot be grouped:
different from
options contradict each other, the right-most
option in the command line takes precedence.
For example, the following command line sets
the value of the symbol

gcc960 -DL=80 -DL=132 proto.c

Note that the gcc960 compiler driver does not
check the command line options for validity.
Invalid options are ignored without producing a
warning message.

On UNIX, the compiler recognizes a letter
preceded by a hyphen (
Windows, the compiler recognizes a letter
preceded by either a hyphen (
an option. For example,
Architecture option for UNIX or Windows.
However, on a Windows system,
specifies the architecture option.

-d -r. When two or more

L to 132:

-) as an option. In

-) or a slash (/) as

-A specifies the

-dr is

/A also

2-2

gcc960 Compiler Driver

2

path

NOTE. Although Windows pathnames require backslashes (\), this
manual shows paths using the forward slash required by UNIX (

filename

@

response-file

identifies the directory containing the file named
by

filename

filename

directory. Each
directory requires a separate

is the name of a source, preprocessed source,
assembly-language, or other file (e.g., linker
directive file) to be processed by the compilation
system. The gcc960 command line allows
specification of more than one

[

path/]filename

Open the named response file and read in its
contents as if they had been typed on the
command line. Response files are a convenient
way to store commonly-used command line
options, and a way to get around the 128­character limit in Windows command lines.

. Not specifying

causes gcc960 to search in the current

filename

.

path

for a

not in the current

path

specification.

/

).

Response files can contain comments. Lines
whose first non-whitespace character is
treated as comment lines, and ignored.

# are

gcc960 Sample Command Lines

This section provides examples of how the compiler is commonly invoked.
All these examples assume that you have C source files named

t2.c and that you are generating code for the i960 CA architecture.

t1.c and

2-3

2

i960 Processor Compiler User's Guide

Preprocessing a Source File

To preprocess a source file, use the command:

gcc960 -E t1.c

-E

informs the compiler to preprocess the source

file and echo the output to stdout.

Generating Assembly Code

To generate assembly code for the i960 CA architecture, use the following
command.

gcc960 -S -ACA t1.c

-S

instructs the compiler to generate assembly code.

-A specifies the i960 CA architecture.

Generating an Object Module with Debug Information

To generate a object module with debug information, use the following
command.

gcc960 -c -g -ACA t1.c

2-4

-g

instructs the compiler to generate debug

information.

-c instructs the compiler to generate an object file.

Generating an Executable

To generate an absolute module (executable file) for a Cyclone board with
a CA processor, use the following command.

gcc960 -ACA -Tmcycx -g -O t1.c t2.c -o test

The above command compiles the modules t1.c and t2.c and links them
with appropriate libraries to generate an absolute module targeted for a
Cyclone i960 Cx evaluation board.

-Tmcycx instructs the compiler that you are targeting a

Cyclone i960 Cx evaluation board.

gcc960 Compiler Driver

-O causes the compiler to perform some basic

optimizations on the generated code.

-o instructs the compiler to name the generated

executable test.

gcc960 Linker Options

2

When you do not specify a target with the T
not attempt to link programs for a specific target board. Unless otherwise
specified,
following linker command is issued:

gld960 -AKB $G960BASE/lib/crt960.o

To link for a different target, you can change the crt (startup) file and add
board and monitor support libraries.

To link for another environment, the options
gcc960 from including the default C startup files or libraries in the link,
allowing them to be fully specified by the user. For example:

gcc960 -crt -nostdlib mycrt.o

You can invoke gcc960 to create object files in either the b.out, COFF or
ELF object module format. The compilation system accepts the
option to generate COFF and the Felf option to generate ELF; these
options override the gcc960 driver's default format option, which is

Fbout.

For more detailed information, see the following discussions of compiler
invocation and options.

.c and .s files are compiled and/or assembled, and the

target

file.

option, gcc960 does

file

.o... -lqf -lc -lm

crt and nostdlib prevent

o... -lc -lmylib

Fcoff

2-5

2

i960 Processor Compiler User's Guide

Table 2-1 lists the linker options that gcc960 passes directly to the linker.

Table 2-1 Linker Options Accepted by gcc960

Option Name Description

e Entry point defines entry point other than default for

beginning execution of program.

gcdm Decision Maker invokes gcdm960 decision maker.
l Archive file specifies an archive file as input.
L Library search adds directories to search for libraries,

configuration files, and startup object files.

r Relocation retains relocation information in the output

object file.

s Strip strips line-number entries and symbol-table

entries from the linker's COFF output file.

u Unresolved

Symbol

introduces an unresolved symbol, causing the
linker to search symbol tables for resolution of
the reference.

2-6

X | x Compress X removes all symbols from the output symbol

table; x removes only local symbols.

y Trace symbol traces a symbol; indicates object files where it

appears; provides other information.

z Time stamp suppresses COFF time stamp in linker output

file.

gcc960 and Predefined Macros

Predefined macros within a program can act as constants during execution
or as values in conditional-compilation statements. Predefined macros
include ANSI-standard macros and macros specific to the i960 processor
architecture. The
macros but not ANSI-standard macros.

U (Undefine) option removes i960 processor-specific

gcc960 Compiler Driver

The following macros are available in accordance with the ANSI standard
for C, as described in the book, C: A Reference Manual:

__DATE__ __FILE__ __LINE__ __TIME__ __STDC__

The following macros are predefined by the compilation system when
invoked with the gcc960 driver program:

__GCC960_VER is defined to a decimal number that can be used

to check the version number of the compiler.
The number is expressed in decimal as

MmmPPPP
mm

is the minor version number, and
internal version number that is used to track the
patch level. So, for example, R5.0 patch level
4032 have

5004032.

__i960 indicates the i960 processor environment. The

compiler defines
macro can be used to identify the parts of a
program specific to the i960 processor.

, where M is the major version number,

PPPP

is an

__GCC960_VER defined to be

__i960 automatically. This

2

__i960

__PIC indicates that the generated code is position-

__PID indicates that the generated data is position-

xx

indicates the i960 processor instruction set in
use. The compiler automatically defines the

__i960
CF, JA, JF, JD, HA, HD, HT, or RP. Definition of

xx

instruction set specified by the
option.

independent. The
(Generate-for-position-independent-code) option
causes the

independent. The
(Generate-for-position-independent-data) option
causes the

xx

macro. The xx is SA, SB, KA, KB, CA,

depends on the specific i960 processor

A (Architecture)

mpic

__PIC macro to be defined.

mpid

__PID macro to be defined.

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i960 Processor Compiler User's Guide

__i960_BIG_ENDIAN__ indicates that the generated code is arranged for

__STRICT_ANSI__ indicates that C constructs not conforming to the

__CHAR_UNSIGNED__ indicates that the plain char type are treated like

gcc960 and File Use

The compiler, assembler, and linker all use filenames specified on the
gcc960 command line to find and create input and output files. In
addition, translation and linking require temporary work files.

Input Files

big-endian address space. The
option causes this macro to be defined.

ANSI standard should be flagged. The
(ANSI) option causes these macros to be
defined.

the

unsigned char type. This is the default.

G (Big-endian)

ansi

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The gcc960 command line allows filename inputs that support
specification of assembly-language files, preprocessed source files, C
source files, object files, and libraries. The compiler driver determines the
type of each input file by the filename extension, as follows:

filename

filename
filename
filename

.c indicates a C source file that can contain macros

and preprocessor directives.

.i indicates a preprocessed C source file.
.s indicates an assembly-language source file.
.S indicates an assembly-language source file that

can contain preprocessor macros and directives.

gcc960 Compiler Driver

The driver passes any other filename to the linker. The linker then
determines whether the file is an object file, library, or configuration file.

Input files not needed for processing are not processed. For example, if
you specify an assembly-language (

S (Assembly) compile into assembly code option, gcc960 takes no action

on the assembly-language file.

filename

.s) file and also specify the

Include Files

The gcc960 command line allows insertion of text from include files. The

#include preprocessor directive causes text insertion.

The I, I- and I. options affect the directories that are searched for the file
specified in the #include directive. These options are described in detail in
the Option Arguments and Syntax section. In the absence of the
gcc960 searches the current directory for #include “file” and

G960BASE/include directory for #include <file>.

I option,

Output Files

2

Specifying the options -E, -S, or -c causes the compilation system to
produce output of the last phase that completes for each primary input file.
Output can be preprocessed source, an assembly-language file, or an
unlinked object file. If no errors occur during processing, the output files
created by these options are usable as input to a future gcc960 invocation.
Table 2-2 lists the compilation phases and their inputs and outputs.

Specifying the
separate list file for each primary C source file. The list file is named by
replacing the .c or .I extension with .L.

Specifying the
for a make tool describing the dependencies of each source file. The

clist and -M options are described in detail in the Option Arguments

and Syntax section.

clist option generates a listing. gcc960 produces a

-M option causes the preprocessor to output rules suitable

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i960 Processor Compiler User's Guide

Table 2-2 Intermediate Inputs and Outputs

Last Phase
Completed Option Inputs Outputs

preprocessing M, E C source files display on standard

compilation S C source files

preprocessed files

assembly c C source files

preprocessed files
assembly files

linking (default) C source files

preprocessed files
assembly files
unlinked object files
relinkable object files
libraries
configuration files

output
assembly-language file

listing files
unlinked object files

listing files

list files
executable file
relinkable object file

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When specifying only one primary input file, the o (Output) option names
a single output file. Specifying multiple primary input files, or not
specifying an output filename, causes gcc960 to use the primary input
filenames to derive corresponding default output filenames with the form

filename.e
filename

, where:

is the primary input filename without its
extension.

e

is a single-letter extension indicating the contents
of a file, as follows:

s indicates an assembly-language file

from the

o indicates an object file from the c

S option.

option.

L indicates a listing file from the

clist option.

gcc960 Compiler Driver

Unless otherwise specified, the destination directory for any output file is
the current working directory. If
destination directory, the compilation system overwrites the existing file.

filename.e

already exists in the

2

.GLD Files

The filename
from the linker, in the absence of an Output option when the compilation
proceeds all the way to the link step. For ELF files, the default is
and for bout files, the default is b.out.

The following examples illustrate the creation and use of output filename
extensions:

• The command

produces the object files proto.o and proto1.o and the listing files

proto.L and proto1.L.

• The command

produces the object file proto_v1.o and the listing file proto.L.

• The command

executable file

The .GLD files provide a convenient mechanism for specifying default
options to the compiler and linker. It also provides a mechanism for
specifying the startup file and the libraries to be linked in. These files are
meant to be used with the gcc960 interface to the tools (GLD is an
acronym for gcc960 linker directive file even though it can be used to pass
options to the compiler as well).

a.out is the default for the executable COFF object file

e.out

gcc960 -c -clist s proto.c proto1.i

gcc960 -c -o proto_v1.o -clist s proto.c

gcc960 -ACA -Tmcycx proto.c produces the

b.out.

By default, the installation program places several
directory [
Cyclone evaluation boards. To illustrate, the sample
below is tailored for the Cyclone i960 Cx processor-based evaluation
board.

$G960BASE]/lib. These files have been tailored to the

.GLD files in the

.GLD file given

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i960 Processor Compiler User's Guide

Example 2-1 Sample .gld File

gcc:-ACA

crt:%{!crt:%[~]/lib/%{mpid:%{G:crt960_e.o}%{!G:crt960_p.o}}
%{!mpid:%{G:crt960_b.o}%{!G:crt960.o}}}

ld:%{!Ttext:-Ttext 0xA0008000}%{*: -defsym
_heap_size=0x20000;_heap_base=(_end+0xf)&~0xf;_heap_end=_heap_base+_heap_size­1;_stackbase=(_heap_end+0x40)&~0x3f -defsym fpem_CA_AC=0x100}

lib:%{!nostdlib:-lmn -lll}

In the .GLD file, you can place any options that the tools accept on the
command line. For example, in the
see options for the gcc960 compiler driver and linker.

.GLD file shown in Example 2-1, you

The command in the
gcc960 compiler driver. This setting is then used throughout the
compilation process. The options following
fashion as if they were specified on the gcc960 invocation line.

The commands in the
component built into them so that options could be included in a
conditional fashion. These sections determine the startup code, linker
options and the libraries that are passed on to the linker.

The

crt: section is used to specify the startup code. In the example

given above, if the
line, then the compiler driver uses the following for the startup code.

[G960BASE]/lib/crt960_e.o if both -mpid and -G options are on
[G960BASE]/lib/crt960_p.o if -mpid option is on -G is off
[G960BASE]/lib/crt960_b.o if -mpid option is off and -G is on
[G960BASE]/lib/crt960.o if both -mpid and -G options are off

gcc: section defines the architecture setting for the

gcc: are treated in the same

crt:, ld:, and lib: sections have a conditional

-crt option has not been specified on the compile

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