Re: Newlib-3.3.0 build failed with gcc-9.3.0 armv6-m

Thank you both for the advice and details.

Laboriously, I arrived at a solution which suits me. Precede the call to
./configure by setting the flag CFLAGS_FOR_TARGET with the following values:

CFLAGS_FOR_TARGET='- mcpu=arm7tdmi -marm -mlittle-endian -mfloat-abi=soft
-O0' ../newlib-3.3.0/configure --prefix = ... etc.

That does the job. Thank you again.

Le mer. 25 mars 2020 à 19:02, Richard Earnshaw (lists) <
[email protected]> a écrit :

> On 21/03/2020 17:45, bitmap kid via Newlib wrote:
> > Hello,
> >
> > When I compile newlib with a gcc-9.3.0, i get the following error :
> >
> > arm-unknown-eabi-gcc
> > -B/home/th/Downloads/newlib-3.3.0-build/arm-unknown-eabi/newlib/ -isystem
> >
> /home/th/Downloads/newlib-3.3.0-build/arm-unknown-eabi/newlib/targ-include
> > -isystem /home/th/Downloads/newlib-3.3.0/newlib/libc/include
> > -B/home/th/Downloads/newlib-3.3.0-build/arm-unknown-eabi/libgloss/arm
> >
> -L/home/th/Downloads/newlib-3.3.0-build/arm-unknown-eabi/libgloss/libnosys
> > -L/home/th/Downloads/newlib-3.3.0/libgloss/arm    -g -O2 -I.
> > -I../../../../newlib-3.3.0/libgloss/arm/.. `if [ -d ./../../newlib ];
> then
> > echo
> -I../../../../newlib-3.3.0/libgloss/arm/../../newlib/libc/machine/arm;
> > fi` -g -O2 -c ../../../../newlib-3.3.0/libgloss/arm/linux-syscalls0.S
> > ../../../../newlib-3.3.0/libgloss/arm/linux-syscalls0.S: Assembler
> messages:
> > ../../../../newlib-3.3.0/libgloss/arm/linux-syscalls0.S:44: Error: SVC is
> > not permitted on this architecture
> > ../../../../newlib-3.3.0/libgloss/arm/linux-syscalls0.S:45: Error: SVC is
> > not permitted on this architecture
> > ../../../../newlib-3.3.0/libgloss/arm/linux-syscalls0.S:46: Error: SVC is
> > not permitted on this architecture
> > [...]
> > ../../../../newlib-3.3.0/libgloss/arm/linux-syscalls0.S:102: Error: SVC
> is
> > not permitted on this architecture
> > ../../../../newlib-3.3.0/libgloss/arm/linux-syscalls0.S:103: Error: SVC
> is
> > not permitted on this architecture
> > make[3]: *** [Makefile:126 : linux-syscalls0.o] Erreur 1
> >
> > Not really surprising, because this GCC is armv6-m default arch, an
> > unavailable coprocessor instructions cpu.
> >
> > Am I at an impasse ?
> >
> > Below, the newlib configure command :
> >
> > ../newlib-3.3.0/configure --prefix=/home/th/armv4vm-cc/
> >   --disable-interwork --disable-newlib-supplied-syscalls --with-gnu-ld
> > --with-gnu-as --disable-shared --disable-nls
> --enable-newlib-io-long-long
> > --enable-newlib-io-long-double  --enable-newlib-io-c99-formats
> > --target=arm-unknown-eabi
> >
> > I I will not hide from you that I have not checked if this version of gcc
> > is compatible with this one from newlib :(
> >
> > I thank you so much to help me to find a work around.
> >
> > thierry
> >
>
> SVC is supported by armv6s-m, which is a minor variant of the
> architecture.  You can use that if you want.
>
> TLDR: the only difference between armv6-m and armv6s-m is how the SVC
> opcode is handled by the hardware.  In armv6s-m there is a specific
> exception mode to handle it.  In armv6-m this exception mode is lacking
> and the instruction will take the undefined instruction exception (which
> can then emulate the instruction if it so desires).  Either can
> therefore support SVC and the only difference is for 'kernel' code that
> has to understand the different behaviours.  There's a small performance
> cost as well, of course, because the instruction has to be decoded first
> if going via the undef instruction trap.
>
> R.
>