Re: [Mingw-users] i386-elf Cross compiler hosted on Windows

[Kai R. <kai...@lu...>]

Steven Graham wrote:

> There seems to be a lot of documentation the other way,
> but I need to make a cross compiler (and binutils of
> course) that is hosted on MinGW on Windows and targeted
> i386-elf. As This is for compiling my own operating system
> Kernel and other own os bits and libraries I don't need
> any linux runtime libraries.
> 
> How do I do this?

 Most probably with big difficulties :(

 The 'i386-elf' target is just the target causing weird
problems, my recent try to update to binutils-2.13.2.1
caused the linker give the error:

  e:/usr/local/lib/gcc-lib/i386-elf/3.2.2/crtbegin.o:
  could not read symbols: File truncated

ie. it claimed the startup produced during the GCC build
being faulty. The toolchain build was done on Linux and
the Linux-hosted binutils (for 'i386-elf') handled this
same startup ok.

 When looking at this, I found both 'as.exe' and 'ld.exe'
being broken. When first replacing the 'ld.exe' with an
older (working) version (expecting only the linker being
broken), the error changed to be:

  D:\temp/cciCaaaa.o:
  file not recognized: File truncated

ie. the startup(s) will be approved but now the 'as.exe'
caused an faulty object file being produced...

 The binutils-2.13.2.1 were produced using gcc-3.2.2 for
MinGW. When trying gcc-2.95.3, the produced binutils were
still broken. Both GCCs had the MSVCRT.DLL as the default
runtime C library. The old working binutils had the older
CRTDLL.DLL as their runtime-DLL...

 Ok, if the runtime-DLL seemed to cause the difference,
then what about producing binutils-2.13.2.1 for CRTDLL.DLL ?
My oldest egcs-1.1.2 based toolchain had this as default,
and building with it then caused seemingly working binutils:

<snip>
 e:\usr\local\lib\gcc-lib\i386-elf\3.2.2\..\..\..\..\i386-elf\bin\as.exe
 --traditional-format -o D:\temp/ccaCaaaa.o D:\temp/ccaoaaaa.s
 e:\usr\local\lib\gcc-lib\i386-elf\3.2.2\..\..\..\..\i386-elf\bin\ld.exe
 -m elf_i386 -o tst_i386-elf.x e:/usr/local/lib/gcc-lib/i386-elf/3.2.2/crtbegin.o
 -Le:/usr/local/lib/gcc-lib/i386-elf/3.2.2 -Le:/usr/local/lib/gcc-lib
 -L/usr/local/lib/gcc-lib/i386-elf/3.2.2
 -Le:/usr/local/lib/gcc-lib/i386-elf/3.2.2/../../../../i386-elf/lib
 -L/usr/local/lib/gcc-lib/i386-elf/3.2.2/../../../../i386-elf/lib
 -Le:/usr/local/lib/gcc-lib/i386-elf/3.2.2/../../.. D:\temp/ccaCaaaa.o
 e:/usr/local/lib/gcc-lib/i386-elf/3.2.2/crtend.o
 -T e:/usr/local/lib/gcc-lib/i386-elf/3.2.2/../../../../i386-elf/lib/cygmon.ld

e:\usr\local\samples>e:\usr\local\i386-elf\bin\readelf -h tst_i386-elf.x
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Intel 80386
  Version:                           0x1
  Entry point address:               0x10000c
  Start of program headers:          52 (bytes into file)
  Start of section headers:          32136 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         2
  Size of section headers:           40 (bytes)
  Number of section headers:         17
  Section header string table index: 14

 I'm going to try the gcc-2.95.3 and 3.2.2 too with the '-mcrtdll'
option and will see if the MSVCRT.DLL really is the big problem
here or if the newer GCCs have problems too...

 BTW, the default config options for the 'i386-elf' in GCC-sources
are not set for any real target... Ok, elves usually are not real
but not all know this yet (in german 'elf' is 'eleven', it is a
French oil-company, means "Earth Liberation Force" and maybe many
other things, like a common object format, but AFAIK not any opsys,
target board etc. which could make it being a 'real target'). So
all problems related to someone thinking elves being real targets
will not get any help from me... The ' -T .../i386-elf/lib/cygmon.ld'
seen previously should tell something to all embedded people, there
is that Cygmon-support in newlib for 'i386-elf', but GCCs then have
something else (and totally unknown elf-magic) as default.

> (P.S If I can't get this to cross compile then I plan to  make
> my os use PE executables and libraries)

 Generally a 'i386-pe' target toolchain shouldn't differ much from
a 'i386-elf' or 'i386-coff' one, but if you consider using the
prebuilt MinGW-tools, prepare to learn defining your own 'specs'
to be used during compiles or to do something equal... Those who
have tried to produce 'i386-wince-pe' executables for the WinCE
emulator-DLLs using plain vanilla MinGW tools probably can help
here (I haven't tried but surely there are people who have tried
to replace MSVC in this job...)

Cheers, Kai