Building a Cross Compiler, Assembler and Linker Designed by Prof. Peng-Sheng Chen

What can You Learn? During embedded-system development, why do we need to use cross compiler, assembler / linker and C standard library How to build cross compiler、assembler / linker

How to build cross C standard library

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Equipment Requirement PC with  Linux

OS installed

 Native

gcc compiler installed

 Internet

access

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Software Requirement  GNU binutils source code (version 2.16.1) 

ftp://sources.redhat.com/pub/binutils/releases/binutils2.16.1.tar.gz



http://ftp.gnu.org/gnu/binutils/binutils-2.16.1.tar.gz

 GNU C/C++ compiler (version 3.3.6) 

ftp://sources.redhat.com/pub/gcc/releases/gcc-3.3.6/gcc3.3.6.tar.gz



ftp://ftp.nctu.edu.tw/computer-languages/C/gcc/releases/gcc3.3.6/gcc-3.3.6.tar.gz

 GNU newlib (version 1.14.0) 

ftp://sources.redhat.com/pub/newlib/newlib-1.14.0.tar.gz

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Outline Introduction Basic Linux commands Build cross assembler / linker Build cross compiler Build cross C standard library Testing

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Outline Introduction Basic Linux commands Build cross assembler / linker Build cross compiler Build cross C standard library Testing

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Introduction  A total solution for embedded system development 

Hardware



Software => software-development tools, applications

 Software-development tools 

Compiler, assembler, linker, debugger and C standard library



Commercial => very high cost



Open source => free. s can modify, distribute and use the software

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GNU Binutils  The GNU binutils are a collection of binary tools  ld - the GNU linker  as - the GNU assembler  Other binary tools 

   

ar - A utility for creating, modifying and extracting from archives gprof - Displays profiling information objcopy - Copys and translates object files objdump - Displays information from object files …

 Easy to port binutils to other platforms  Suitable for embedded-system development 8

GNU C/C++ Compiler  Retargettable  Available from the Free Software Foundation 

GPL Licensed



Free

 Written by Richard Stallman originally (FSF)  Front-end, back-end system with for many of each  Code quality is better than some known compiler, very close to DEC’s compiler on Alpha  Supplied as vendor compiler by NeXT, BeOS, Linux, BSD 9

Front Ends  C、C++、Objective C  Ada 95 (GNAT)  Fortran77、Fortran95  Pascal  Modula-2、Modula-3  Java (ed from gcc 3.0)  Java->Bytecode, Bytecode->native code  Java->Native code  Cobol  Chill (Cygnus, a language in the Modula II family used in European telecommunications ) 10

Machines ed by GCC  Essentially all machines in widespread.  Acorn (Advanced) RISC Machine.  Alpha (DEC)  Intel x86 Families、i860、i960.  Motorola 680x0、68C11、DSP56000  Hitachi SH、H8300  MIPS、IBM PowerPC、HP PA-RISC、SUN SPARC  ……  Intel IA64, AMD x86-64  Cell processor (used by PS3) 11

GCC Execution

gcc

p

cc1 g++

gas (assembler)

Input file output file

ld (linker)

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GNU C Standard Library GLIBC Newlib A

C standard library intended for use on embedded systems  Usually work on any architecture with the addition of a few low-level routines

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Cross System-Development Tools  The characteristics of most embedded systems 

Limited memory



Diskless



No output screen



Poor performance



…

Cross-compiler Remote debug

 Sometimes, it is impossible to execute compiler, assembler / linker and debugger on target platform

 For embedded system, we need cross systemdevelopment tools to help software development 14

Machine Classification Build machine  The

machine builds cross-toolchains

Host machine  The

machine cross-toolchains will execute on

Target machine  The

assembly code of the machine crosstoolchains will produce output for

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Machine Identification Three items to identify machine  U type  Company name  System type Example  vax-dec-ultrix4.2  i386-redhat-linux  m68k-coff  arm-elf 16

Outline Introduction Basic Linux commands Build cross assembler / linker Build cross compiler Build cross C standard library Testing

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Basic Linux Commands (1) Command cd cd /home

Description Change directory Change the current working directory to /home

cd ..

Move to the parent directory of the current directory Move to the 's home directory

cd ~

Copy files file1 file2 Copy the file “file1” to the file “file2”

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Basic Linux Commands (2) Command df

Description Show the amount of disk space used on each mounted filesystem

ls ls

List files List files in the current working directory except those starting with . and only show the file name List all files in the current working directory in long listing format showing permissions, ownership, size, and time and date stamp

ls -al

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Basic Linux Commands (3) Command cat

Description Sends file contents to standard output cat /etc/hosts Sends the contents of the “/etc/hosts" file to the screen less

Similar to the more command, but the can page up and down through the file

less file1 The example displays the contents of file1

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Basic Linux Commands (4) Command more

Description Allows file contents or piped output to be sent to the screen one page at a time more /etc/hosts Lists the contents of the "/etc/profile" file to the screen one page at a time ls –al |more Performs a directory listing of all files and pipes the output of the listing through more. If the directory listing is longer than a page, it will be listed one page at a time

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Basic Linux Commands (5) Command rm rm file1

Description Delete the files Delete the file “file1”

mv Move or rename files mv file1 file2 Move the file from “file1" to “file2". This effectively changes the name of “file1" to “file2” mv file1 . Locates binaries and manual pages for the ls command

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Basic Linux Commands (6) Command pwd

Description Show the name of the current working directory

whereis

Show where the binary, source and manual page files are for a command Locates binaries and manual pages for the ls command

whereis ls

man man ls

format and display the on-line manual pages Display the on-line manual of “ls” 23

Setting Environment Variables (1) Command ps

Description Report process status

Which shell do you use? $ ps PID TTY 13580 pts/11 13626 pts/11 $

TIME CMD 00:00:00 bash 00:00:00 ps

$ ps PID TTY 13580 pts/11 13626 pts/11 $

TIME CMD 00:00:00 csh 00:00:00 ps

Bash Shell

C shell 24

Setting Environment Variables (2) Set PATH  Ex:

Add “/foo/bin” to PATH

$ export PATH=/foo/bin:$PATH

Bash Shell

$ setenv PATH /foo/bin:$PATH

C shell

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formation: Redirection Before a command is executed, its input and output may be redirected  Executable

file: myexec  Log file: log.txt  Direct both standard output and standard error to the file “log.txt”

Bash Shell

$ myexec

>

$ myexec

>&

log.txt log.txt

2>&1 C Shell 26

Outline Introduction Basic Linux commands Build cross assembler / linker Build cross compiler Build cross C standard library Testing

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Build Cross-Binutils  source code of GNU binutils  uncompress source code  configure binutils 

This step will detect system status, adjust related building parameters and generate corresponding Makefile file



--target=arm-elf sets target machine for ARM, and ed file format for ELF



--prefix=/foo sets the package will be installed in directory /foo

configure --target=arm-elf --prefix=/foo  make

 make install 28

Outline Introduction Basic Linux commands Build cross assembler / linker Build cross compiler Build cross C standard library Testing

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Build Cross-Compiler (1)  Add the directory of binutils executable to PATH  source code of GNU gcc  uncompress source code  configure gcc  

  

This step will detect system status, adjust related building parameters and generate corresponding Makefile file --target=arm-elf sets target machine for ARM, and ed file format for ELF (The setting should consist with the setting in binutils) --prefix=/foo sets the package will be installed in directory /foo (The setting should consist with the setting in binutils) --enable-languages=c sets front-end will C (That is we will build C compiler only) --with-newlib sets the compiler will use newlib as standard C library 30

Build Cross-Compiler (2) configure --target=arm-elf --prefix=/foo --enable-languages=c --with-newlib

 make  make install

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Outline Introduction Basic Linux commands Build cross assembler / linker Build cross compiler Build cross C standard library Testing

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Build Cross-Newlib  Add the directory of binutils、gcc executable to PATH  source code of GNU newlib  uncompress source code  configure newlib  



This step will detect system status, adjust related building parameters and generate corresponding Makefile file --target=arm-elf sets target machine for ARM, and ed file format for ELF (The setting should consist with the setting in binutils and gcc) --prefix=/foo sets the package will be installed in directory /foo (The setting should consist with the setting in binutils and gcc)

configure --target=arm-elf --prefix=/foo

 make  make install 33

Directory Structure /foo

bin include lib gcc-lib arm-elf

bin

man

include

info

lib

share 34

Outline Introduction Basic Linux commands Build cross assembler / linker Build cross compiler Build cross C standard library Testing

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Testing /foo/bin/arm-elf-gcc -S test1.c /* test1.c */ #include <stdio.h> int main(void) { printf(“Hello World\n”); return 0; }

.LC0:

main:

.L3: .L2:

.file "test1.c" .section .rodata .align 2 .ascii .text .align .global .type

"Hello World\n\000" 2 main main, %function

@ args = 0, pretend = 0, frame = 0 @ frame_needed = 1, uses_anonymous_args = 0 mov ip, sp stmfd sp!, {fp, ip, lr, pc} sub fp, ip, #4 ldr r0, .L2 bl printf mov r3, #0 mov r0, r3 ldmea fp, {fp, sp, pc} .align

2

.word .size .ident

.LC0 main, .-main "GCC: (GNU) 3.3.6"

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Reference Linux/UNIX commands  http://www.computerhope.com/unix.htm#04

GNU binutils  http://sources.redhat.com/binutils

GCC  http://gcc.gnu.org

GNU newlib  http://sources.redhat.com/newlib 37