embedded gcc linker issue--trying to build for m68000 cpu

You can get the sources for libgcc and rebuild it with the target-specific options you need, giving you an optimized (and appropriate) libgcc.a. You already have the right compiler for it :-)

Don't know your compiler etc. stuff, but 68k and coldfire are not that compatible - either way, each has opcodes the other one does not support. Coldfire uses only a subset of the 68000 opcodes, and I am pretty sure I have seen different coldfires which have some own new ones the 68000 did not use.

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Original message:

Which cpu? Code Sourcery gcc supports a large number of m68k family devices - there may be a closer match than -m68000.

Are you calling the linker using "m68k-elf-ld" or "m68k-elf-gcc"? Normally, you want to use "gcc" rather than calling "ld" directly.

You should not need "-lgcc". Using "gcc" as the driver for the linker, it should be able to figure out which basic libraries are needed, and match them up for your cpu.

Have you read the "getting started" guide that comes with Code Sourcery downloads?

The latest version is now at gcc 4.4, if you want to keep up to date. That won't make any difference to your current issue, of course.

What are your full command lines?

CodeSourcery maintain and support gcc for a number of targets. The "ColdFire" and "m68k" target are the same, since the architecture is fundamentally the same. The port supports a wide range of m68k variants, including (AFAIK) all the current ColdFire cores and almost all 68k cores that were made. Libraries suitable for any of these cores are also included. While it is not impossible that you have a cpu core that is not supported, I think it is unlikely - it is much more likely that you are giving the compiler and the linker conflicting information about the core and the libraries you want.

Linux 2.2 is /very/ old. Getting a modern gcc cross-compiler working on such a system will be a challenge - you probably won't be able to compile the current gcc source code with the older compiler and tools you have on the system at the moment, and your distribution is unlikely to have ready-to-run current gcc (plus make, binutils, etc.) binaries. This means you would have to build an intermediary native gcc from sources (all released versions are available from the FSF archives), use that to build a current native toolchain, and then use that to build the cross-compiler. It's fun if you like that sort of thing...

If you want to use Linux for development work, I'd advise joining the

21st century - it's a lot easier using a modern system (you can then use the binaries directly from CodeSourcery if you want).

For windows gcc builds, you really want to use MinGW/MSys these days - it's much faster (both the build process, and the resultant binaries) than with cygwin, and avoids all the "cygwin1.dll" issues.

Of course, this is all fairly academic - building your own cross-compiler is mostly just for those that are interested in that sort of thing, since the pre-build binaries work perfectly well.

CodeSourcery also have a mailing list that you can join, and paid support if you want that.

mvh.,

David

Don't know if this will be relevant, but here some lines from a makefile from around 1992, using gcc2.7.2 cross to dragonball 68000:

ROOT = /usr/local/aerosys/sw-lib

SYSINC = $(ROOT)/sys-include SYSLIB = $(ROOT)/sys-lib

SRCDIR = $(ROOT)/bsp/cms-qf200/src INCDIR = $(ROOT)/bsp/cms-qf200/inc OBJDIR = $(ROOT)/bsp/cms-qf200/obj LSTDIR = $(ROOT)/bsp/cms-qf200/lst LIBDIR = $(ROOT)/bsp/cms-qf200/lib SCRIPTDIR = $(ROOT)/bsp/cms-qf200/script

CC68ROOT = /usr/local/gcc-68k CC68LIB = $(CC68ROOT)/m68k-coff/lib/m68000 CC68LIBS = libc.a libm.a

LIBGCC = $(CC68ROOT)/lib/gcc-lib/m68k-coff/2.7.2.3/m68000/libgcc.a

and

# CC = cc68k CFLAGS = -O2 -m68000 -ansi -Wall -fomit-frame-pointer -fvolatile

-nostdinc -I- CC68INC = /usr/local/gcc-68k/m68k-coff/include

AS = as68k ASFLAGS = -m68000

AR = ar68k ARFLAGS = crvs

LD = ld68k LDSCRIPT = -T$(SCRIPTDIR)/bsp.ld LDFLAGS = $(LDSCRIPT) -t -cref -Map bsp.map

This was originally running under tru64 alpha, but also later on sparc sol10. Gcc 2.7.2 is fairly old, but was quite mature at that point, produces reasonable code and was able to build the toolchain without too much trouble on what was and is an unsupported platform...

Regards,

Chris

^^^^

Correction, should be 2002...

Regards,

Chris

It looks to me like a bug, a simple

x.c: int main() { return 0; }

m68k-elf-gcc -o x.elf -m68000 x.c

gives also below error:

Jim, maybe you really need to check if 68000 is still supported by newer gcc ?

--
42Bastian
Do not email to bastian42@yahoo.com, it's a spam-only account :-)
Use @monlynx.de instead !

Looking at that again, it looks like the libgcc.a, which is processor specific and required by the compiler, iirc, to resolve some instructions, is being pulled in from the wrong place.

On my makefile:

LIBGCC = $(CC68ROOT)/lib/gcc-lib/m68k-coff/2.7.2.3/m68000/libgcc.a

libgcc.a comes from a separate cpu specific directory. Have a look to see if there is any similar directory structure for 4.2.1...

Regards,

Chris

... ...

Thinking outside the square ...

The 680x0 development tools I use include a cross-assembler running on DOS / Windows, a Modula-2 compiler on MacOS, the Digital Research C compiler running on CPM/68K and two Pascal compilers targeting Palm PDAs. I may be able to advise better knowing more about your requirements:

Does your target system have an OS? If so what is it?

Is C an absolute requirement for the programming language?

Are you writing code from scratch, adapting existing code or hoping to just recompile existing code?

What is the preferred format of the resulting object files / executables?

-- Chris Burrows CFB Software Armaide: ARM Oberon-07 Development System

The 68000 certainly is still supported by gcc, and CodeSourcery's builds of gcc support it fine for the compiler and binutils. However, it looks like there are no pre-built libraries for the 68000 in their binaries (at least, in the version I have installed on my machine). Assuming the OP really is using a 68000 and not a different m68k device (such as a

68020), then I'd recommend asking on the CodeSourcery mailing list. They'll be able to give more information, such as whether these libraries are available pre-built in the paid-for versions of the tools, or for tips on how to build the libraries yourself.

That should never be necessary. GCC already puts -lgcc into the linker command line it builds, whenever that serves a useful purpose.

More to the point, GCC would probably have to be built with multilib support to allow switching between incompatible variants of the same basic CPU architecture. That would include multiple copies of libraries such as libgcc, the Standard C++ runtime, and startup code as needed, and the gcc driver program would automatically pick those needed for the chosen architecture.

For whatever reasons, your GCC apparently wasn't built that way. Maybe you need to pick a different package. Or, who knows, you may even have to bite the bullet and build your own GCC tool chain.

CodeSourcery gcc (for the ColdFire, anyway - I don't know about other targets) /is/ built with multilib. It's just that they don't supply pre-built libraries for all the architectures supported by the compiler

- pure 68000 is so old that it's rarely used. Mind you, other devices such as the 68332 are still very much in use, and there are no pre-built libraries for the CPU32 core either - the downloadable binaries (in the "lite" version anyway) only include ColdFire libraries.

First, I'd like to thank everyone for their input! Second, I'd like to answer some of the questions so no one feels left out:

- The target cpu is truly a 68000 core (the old Dragonball EZ328). Now, to avoid the "why": it's a Palm pda which has a display and formfactor that I need and it's cheap.

- I'm using my own OS on the embedded system (no Linux).

- Now that I think about it, I upgraded my Linux box to 2.4, so I'm not that "ancient" :). I have a 2.6 one at work. I want to do my development work in MS Windows, but I could build libgcc on Linux, if I have to).

- I read the GettingStarted guide and I looked at all the libgcc.a files: all seem to be ColdFire based :(.

- I'm coding mostly from scratch. However, I'm using a modified GDB stub from David Williams.

- The only two languages I'll consider using for embedded projects are C and C++ (plus the little bit of necessary assembly). It's what I'm really familiar with.

- I don't really care if the object code is COFF or ELF. The executable has to be straight binary though.

- I use gcc for linking. But I still need to explicitly say -lgcc because of the -nodefaultlibs linker flag (I think). For the sake of completeness, my compile and link lines are:

m68k-elf-gcc -o bin/main.o -m68000 -I. -I../shared -fno-exceptions - Wall -Wa,-m68000 -ggdb -c main.c

m68k-elf-gcc -Wl,-T,RadioTest.ldi bin/MyStartup.o bin/main.o bin/ Timer.o -o bin/RadioTest.elf -m68000 -I. -I../shared -fno-exceptions - Wall -Wa,-m68000 -ggdb -Wl,-Map,bin/RadioTest.map,--cref -nostdlib - nostartfiles -nodefaultlibs -lgcc

So, I think the general consensus is I only get ColdFire micro support with CodeSourcery and I agree with this. I can understand why CodeSourcery may want to ignore older cores. However, don't they still make micros with that (68000 based) core? I might email them, but since I'm using the free version, I feel funny bothering them with this (they do need to earn a living). Purchasing it would be a real gamble since they do say it's a ColdFire compiler on their website (and for home use, it's kinda a pricey gamble).

I'm gonna try two things. First, I'll look for other precompiled binaries for MS Windows. Maybe I'll luck out. I came across one the other day, but now can't remember for the life of me who made it--I'm sure it'll turn up in a search.

Second, I'll see if I can build libgcc. I assume I'll get the source to this when I download the source to gcc. David suggested I use MinGW. I'm pretty sure I'll need "configure" and maybe autoconf & automake. I'm not familiar with MinGW: does that package have them?

I just got an idea. PrcTools was a MS Windows compiler for that very micro. I remember trying it, but it was a limited 16b compiler trying to be compatible with the Palm OS. However, I might be able to use its libgcc. The only issue is that compiler is so old it's probably COFF based (and of course CodeSourcery is ELF). Nothing's ever easy. :)

Well, thanks again for your help everyone. I'll post what I finally end up with (in case anyone else needs the info).

Jim

Funny, have such lying around and waiting for a project :-)

Why not just add the needed functions to your project ? I mean, LD will complain about missing __???? and you just pull the source and that's it. I wouldn't bother building libgcc.a

Yes, please do so.

--
42Bastian
Do not email to bastian42@yahoo.com, it's a spam-only account :-)
Use @monlynx.de instead !

The compiler will generate the libgcc.a calls when it feels them needed. There's little that the programmer can control here.

Contrary to the C library, libgcc.a is needed nearly always when GCC generates code. You cannot skip it.

(Been there, done that - GCC ports to ARM/Thumb at GCC 2.95 time)

--

Tauno Voipio

If you hit a brick wall with gcc check out the Manx Aztec C68K MS-DOS cross-compiler. AFAIR Aztec C had a great reputation in the 1980's.

The software rebundled for Windows XP is here:

The manual is here:

-- Chris Burrows CFB Software

If you are working with dragonball, there were loads of sites out there a few years ago and some are most likely still around, Mark Wyman's site was one, another called dragonball developers lair and there were others. I only stopped using 328 series because it went eol at motorola. Was not pleased and needless to say, I won't be using their product in the future :-(.

I used the vz328 and built the tool chain from source, originally gcc

2.7.2. It wasn't the latest version, but found it more than up to the task. It was rebuilt for solaris 10 on sparc a year or two ago with version gcc 2.95.1, binutils 2.1 and newlib-1.8.2. 2.95 produces pretty good code and seems bug free, so there's no real point in upgrading to a later version, which seems to get more difficult to build from source with every revision.

If you need sol10 sparc binaries for the toolchain, let me know...

Regards,

Chris

These days, gcc and related tools can all be built happily on windows with mingw and msys. Building on Linux can be much faster and easier, especially if you want to do the optional parts like building the man pages or using the autoconf stuff, but for the compiler and libraries there should be no real problem - if you still want to do that. The source download from CodeSourcery should give you what you need, in addition to mingw and msys. You may need to get a few of the extra mingw/msys packages.

Yes, it looks very much like that's the only libraries they have pre-built. But the compiler certainly supports it the 68000 devices.

An alternative idea is just to find some older binaries from around the net. CodeSourcery always has the latest versions with the newest features, since they are the maintainers, but there are plenty of other builds around. Development tool resellers and debugger vendors often have packages to download - try some and see if you get the right libraries there, saving you some effort. For example,

The support for the free version is a mailing list. You don't get any guarantees of an answer, and it might be from another user rather than a CodeSourcery developer, but my experience is that they are helpful regardless of whether or not the poster is a customer. You should feel entirely free to post to these lists. They will also be able to tell you whether the commercial versions of their tools have the right pre-built libraries (you can also download a 30-day trial version of those tools).

Another mailing list of possible interest is snipped-for-privacy@wildrice.com.

I can't remember off-hand if you get autoconf and automake with the standard mingw/msys packages - it's a while since I installed a new version of these tools, and the packaging has changed a little since then. But you can certainly find out about them on the mingw and msys websites.

You probably don't want to mix libgcc from a different version than the gcc compiler. libgcc is a support library for the compiler, and is closely tied to it - it's not like the standard C library that can be replaced.

Problem solved. I looked at the libc files and they were pretty simple. I think there was only one macro definition I had to figure out. But, then I realized my next step would be to build newlib and that wasn't gonna be that simple.

I looked at a bunch of pre-built stuff (thanks again everyone for the links--I may compare the Aztec C output to gcc someday). I decided I really wanted GNU because I know the debugger works with Eclipse. By the way, the other pre-built gcc I was thinking of was

It had everything I needed, but, unfortunately, there was a flaw with it (either the binary wasn't produced correctly or gdb didn't load it correctly--I didn't look into it further). One other by ASH WARE was too old (2.95 and coff based--I wasn't sure an elf type gdb would handle it). The Macgregor (sp?) didn't run (I need a cygwin dll).

So, I ended up building gcc and newlib using mingw/msys like David suggested. I was intrigued by the idea. I'm still gonna use CodeSourcery's gcc though (I figure they ran some of the gcc tests). I'll just link to the libc, libgcc, etc. produced by me (so far tests show it's ok). It wasn't TOO bad building the libs. There were some tricks to get things to build right--I spent some time doing searches. I think the biggest thing to remember is that many tools want you to do these three things: (1) create a folder outside of the source tree to hold intermediate files. (2) run configure and build from the folder created in (1) (3) Use a RELATIVE path when running configure in (2). You can get weird compile errors otherwise. Unfortunately many docs have scripts that use the full path (including the one at mingw). Maybe this used to work for older gcc.

One last thing: gcc needs to build mpfr and gmp. It turns out for the 4.2.1 and 4.4.2 releases I did, all you have to do it place the source in the gcc folder (omit the -version part of the folder name). I'm sure there's other ways to do it as well.

Well, thanks again everyone for all of your input! It was fun (for me anyways)!!

Jim

Thanks for follow-up Jim.

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42Bastian
Do not email to bastian42@yahoo.com, it's a spam-only account :-)
Use @monlynx.de instead !