how to specify the endianess for target machine?

how to specify the endianess for target machine?

[cyclops]

In order to port GCC-4.0.0 to a new target machine, how to specify the
endianness of the target machine? Through configure file or Header
files?

I read the gccint, but can not find how to do it.

Any suggestion would be nice.

I can already compile the whole gcc-4.0.0 for my target machine,
however when I use the gcc to compile the newlib, I got an error:

Making all in stdlib
make[3]: Entering directory
`/home/zeal/z64/build/dirnewlib/z6464-linux-elf/newlib/libc/stdlib'
z6464-linux-elf-gcc
-B/home/zeal/z64/build/dirnewlib/z6464-linux-elf/newlib/ -isystem
/home/zeal/z64/build/dirnewlib/z6464-linux-elf/newlib/targ-include
-isystem /home/zeal/z64/src/newlib-1.10.0/newlib/libc/include
-DPACKAGE=\"newlib\" -DVERSION=\"1.10.0\"  -I.
-I/home/zeal/z64/src/newlib-1.10.0/newlib/libc/stdlib  -O1
-I../../targ-include
-I/home/zeal/z64/src/newlib-1.10.0/newlib/libc/../libc/include
-fno-builtin      -O1 -w -c
/home/zeal/z64/src/newlib-1.10.0/newlib/libc/stdlib/__adjust.c
In file included from
/home/zeal/z64/src/newlib-1.10.0/newlib/libc/include/math.h:10,
                from
/home/zeal/z64/src/newlib-1.10.0/newlib/libc/stdlib/std.h:5,
                from
/home/zeal/z64/src/newlib-1.10.0/newlib/libc/stdlib/__adjust.c:7:
/home/zeal/z64/src/newlib-1.10.0/newlib/libc/include/machine/ieeefp.h:199:2:
error: #error Endianess not declared!!
make[3]: *** [__adjust.o] Error 1

It seems this is because of the Endianess problem.

Thanks!

Re: how to specify the endianess for target machine?

[Ian Lance Taylor]

cyclops <cyclops64@gmail.com> writes:

> In order to port GCC-4.0.0 to a new target machine, how to specify the
> endianness of the target machine? Through configure file or Header
> files?
> 
> I read the gccint, but can not find how to do it.

Look again:
    http://gcc.gnu.org/onlinedocs/gccint/Storage-Layout.html
Look at BITS_BIG_ENDIAN, BYTES_BIG_ENDIAN, WORDS_BIG_ENDIAN, all of
which appear in the tm.h file.

> /home/zeal/z64/src/newlib-1.10.0/newlib/libc/include/machine/ieeefp.h:199:2:
> error: #error Endianess not declared!!

Oh, that's a completely different problem.  Look at that file.  See
how each processor does something like

#ifdef __cputype__
#define __IEEE_BIG_ENDIAN
#endif

Ian