Bare Bone Arm-Elf-Gcc

[J. Johnston]

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
>>>
> 
>>>>
>>>>
>>>>--
>>>>http://www.iol.ie
>>>
>>>
>>--
>>http://www.iol.ie
>>
> 
> --
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