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Re: Bare Bone Arm-Elf-Gcc


Well, for starters you haven't removed the problem of having the
syscalls in newlib.  Because they are in libc, you can't simply
add your own library to replace them.

I will soon be checking in a patch to add the configuration option I
mention below.

Now, regarding modifying libnosys.  What modifications did you have in mind?
It currently is a generic default stub library meant to patch up any library
missing syscalls.  It doesn't supply _exit so in itself is not complete.
I don't see much value-add in making this platform-specific / board-specific
as there is already a system in place for building platform-specific / board-specific
libraries.

-- Jeff J.


David Mc Kenna wrote:
Jeff,

What would the difference be in just modifying the libnosys directory and then
you could just pass the -lnosys option to gcc?

Dave


Dave,

 From the newlib/libgloss side, I have been thinking about this and I
propose that newlib adds a configuration option that tells newlib not to
supply low-level syscalls.  This would allow you to build newlib without
the RDI/RDP syscalls.  You should then place your new code
in the libgloss/arm directory and build a separate library, crt0, and ld
script which specifies both your library and your crt0.  You can then
use the compiler -T option to specify your ld script.

 The configuration options solves a long-standing problem regarding older


platforms that put the syscall code in newlib and it really should be
in libgloss.  We could copy the existing code over to libgloss and eventually

remove the problem by syncing up a default ld script with the compiler folks.

-- Jeff J.

David Mc Kenna wrote:

Hi all,

I have successfully compiled gcc v3.2.1, binutils v2.13 and newlib v1.10


on

cygwin for Arm-elf.

From these programs I have compiled and run, on hardware, several programs


doing

math functions,etc. .
I have come across problems when I try to do printf and scanf statements.


My

main problem is that from delving into newlib/libc/sys/arm/syscalls.c that


printf

and scanf require RDI or RDP i.e. Angel or Demon, installed on the chip,


which

I don't have.

To get over this I have encoded a software UART using bit banging in assembly


and I would like gcc to use this function by default for I/O from the chip.


What is the easiest way to implement this? Is it by modifying syscalls.c


or

going in via libgloss?

Below is my compile script

Any help is appreciated

Thanks,
Dave



cd $gccver
ln -s ../$newlibver/newlib newlib
ln -s ../$newlibver/libgloss libgloss

cp /home/PCAdmin/script/t-arm-elf $src_root/$gccver/gcc/config/arm


cd $src_root/BUILD/binutils && \rm -rf *
../../$binutilsver/configure \
   --with-included-gettext --enable-interwork --with-cpu=arm7tdmi \
   --target=$target --host=$host --build=$build --enable-multilib -disable-shared


\
   --prefix=$prefix -v >  ../logs/$target-$binutilsver-configure.log 2>&1


# 	Make Binutils

make -w all install > ../logs/$target-$binutilsver-make.log 2>&1


cd $src_root/BUILD/gcc && rm -rf *

$src_root/$gccver/configure \
    	--with-newlib --without-headers --with-gnu-as --with-gnu-ld --enable-win32-registry


\
    	--target=$target --prefix=$prefix --exec-prefix=$prefix --host=$host


\
	--enable-multilib --enable-interwork --disable-shared --enable-languages=c


../logs/$target-$gccver-bootconf.log 2>&1

make all-gcc install-gcc > ../logs/$target-$gccver-bootmake.log 2>&1

cd $src_root/BUILD/newlib
$src_root/$newlibver/configure --target=$target --prefix=$prefix > ../logs/$target-$newlibver-conf.log


2>&1

make all install > ../logs/$target-$newlibver-make.log 2>&1

cd $src_root/BUILD/gcc && rm -rf *

$src_root/$gccver/configure \
   --enable-languages=c,c++ \
   --target=$target --host=$host --build=$build --enable-win32-registry


\

   --with-newlib \
   --prefix=$prefix \
   --exec-prefix=$prefix \
    --enable-multilib --enable-interwork \
   --with-gnu-as --with-gnu-ld  -v > ../logs/$target-$gccver-fullconf.log


2>&1

make -w all-gcc install-gcc > ../logs/$target-$gccver-fullmake.log 2>&1



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