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

2 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

3 Equipment Requirement  PC with  Linux OS installed  Native gcc compiler installed  Internet access

4 Software Requirement  GNU binutils source code (version )  ftp://sources.redhat.com/pub/binutils/releases/binutils tar.gz ftp://sources.redhat.com/pub/binutils/releases/binutils tar.gz   GNU C/C++ compiler (version 3.3.6)  ftp://sources.redhat.com/pub/gcc/releases/gcc-3.3.6/gcc tar.gz ftp://sources.redhat.com/pub/gcc/releases/gcc-3.3.6/gcc tar.gz  ftp://ftp.nctu.edu.tw/computer-languages/C/gcc/releases/gcc /gcc tar.gz ftp://ftp.nctu.edu.tw/computer-languages/C/gcc/releases/gcc /gcc tar.gz  GNU newlib (version )  ftp://sources.redhat.com/pub/newlib/newlib tar.gz ftp://sources.redhat.com/pub/newlib/newlib tar.gz

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

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

7 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. Users can modify, distribute and use the software

8 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

9 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 support 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

10 Front Ends  C 、 C++ 、 Objective C  Ada 95 (GNAT)  Fortran77 、 Fortran95  Pascal  Modula-2 、 Modula-3  Java (supported 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 )

11 Machines Supported 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)

12 GCC Execution

13 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

14 Cross System-Development Tools  The characteristics of most embedded systems  Limited memory  Diskless  No output screen  Poor performance  …  Sometimes, it is impossible to execute compiler, assembler / linker and debugger on target platform  For embedded system, we need cross system- development tools to help software development

15 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 cross- toolchains will produce output for

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

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

18 Basic Linux Commands (1) CommandDescription cdChange directory cd /home Change the current working directory to /home cd.. Move to the parent directory of the current directory cd ~ Move to the user's home directory cpCopy files cp file1 file2 Copy the file “file1” to the file “file2”

19 Basic Linux Commands (2) CommandDescription dfShow the amount of disk space used on each mounted filesystem lsList files ls List files in the current working directory except those starting with. and only show the file name ls -al List all files in the current working directory in long listing format showing permissions, ownership, size, and time and date stamp

20 Basic Linux Commands (3) CommandDescription catSends file contents to standard output cat /etc/hosts Sends the contents of the “/etc/hosts" file to the screen lessSimilar to the more command, but the user can page up and down through the file less file1 The example displays the contents of file1

21 Basic Linux Commands (4) CommandDescription moreAllows 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

22 Basic Linux Commands (5) CommandDescription rmDelete the files rm file1 Delete the file “file1” mvMove 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

23 Basic Linux Commands (6) CommandDescription pwdShow the name of the current working directory whereisShow where the binary, source and manual page files are for a command whereis ls Locates binaries and manual pages for the ls command manformat and display the on-line manual pages man ls Display the on-line manual of “ls”

24 Setting Environment Variables (1)  Which shell do you use? CommandDescription psReport process status $ ps PID TTY TIME CMD pts/11 00:00:00 bash pts/11 00:00:00 ps $ $ ps PID TTY TIME CMD pts/11 00:00:00 csh pts/11 00:00:00 ps $ C shell Bash Shell

25 Setting Environment Variables (2)  Set PATH  Ex: Add “ /foo/bin ” to PATH $ export PATH=/foo/bin:$PATH $ setenv PATH /foo/bin:$PATH Bash Shell C shell

26 Log Information: 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” $ myexec > log.txt 2>&1 Bash Shell $ myexec >& log.txt C Shell

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

28 Build Cross-Binutils  download 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 supported file format for ELF  --prefix=/foo sets the package will be installed in directory /foo  make  make install configure --target=arm-elf --prefix=/foo

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

30 Build Cross-Compiler (1)  Add the directory of binutils executable to PATH  download 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 supported 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 support C (That is we will build C compiler only)  --with-newlib sets the compiler will use newlib as standard C library

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

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

33 Build Cross-Newlib  Add the directory of binutils 、 gcc executable to PATH  download 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 supported 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)  make  make install configure --target=arm-elf --prefix=/foo

34 Directory Structure

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

36 Testing  /foo/bin/arm-elf-gcc -S test1.c

37 Reference  Linux/UNIX commands   GNU binutils   GCC   GNU newlib 