Building a gcc cross compiler for ARM

(using Cygwin for windows or Linux)

-------------------------------------

 by David Welch



get



binutils-2.xxxx.tar.gz (currently 2.11.2)

gcc-core-3.xxxx.tar.gz (currently 3.0.4)

newlib-1.9.0.tar.gz (has not changed in a while)



mkdir /arm

cd /arm

tar xzvf binutils-2.xxx.tar.gz

tar xzvf gcc-core-3.xxx.tar.gz

tar xzvf newlib-1.9.0.tar.gz



PATH=/arm/bin:$PATH ; export PATH



mkdir build

cd build



mkdir binutils

cd binutils



/arm/binxxx/configure --target=arm-thumb-elf --prefix=/arm



make all install



cd /arm/gcc-3.xxxx/gcc/config/arm/



Add



#define HAS_INIT_SECTION



to beginning of elf.h file



cd /arm/build

mkdir gcc

cd gcc



/arm/gcc-2.95.2.1/configure --target=arm-thumb-elf --prefix=/arm --without-libs



in /arm/build/gcc/gcc/Makefile



change FROM:

# Additional target-dependent options for compiling libgcc2.a.

TARGET_LIBGCC2_CFLAGS =



TO:

# Additional target-dependent options for compiling libgcc2.a.

TARGET_LIBGCC2_CFLAGS = -Dinhibit_libc



cd /arm/build/gcc

make all install



cd /arm/newlib-1.9.0/newlib/libc/sys/arm/



edit libcfunc.c and syscalls.c



blow away all the swi stuff and basically make everything an

empty shell:



function

{

    return(0);

}



at some point you need to tailor this crt0.S to your needs

(setup the stack pointer, clear the bss mem, and jump to main)

then save the resulting crt0.o in /arm/arm-elf/lib/



cd /arm/build

mkdir newlib

cd newlib



/arm/newlib-1.9.0/configure --target=arm-thumb-elf --prefix=/arm



I have seen someone mention changing the compile option from -O2 to -O3 to produce a

better (faster) performing library, this would be the time to do it...I think you would

be looking for the TARGET CFLAGS in one of the high up Makefiles.



make all install



if you didnt fix the crt0.o files you need to find them and blow them away now

cd /arm

find |grep crt0.o





To use the executables:



PATH=/arm/bin:$PATH ; export PATH



(or just add /arm/bin to your path)





All the gnu programs have arm-thumb-elf- on the front of the file name (arm-thumb-elf-gcc,

arm-thumb-elf-as, etc).