Re: What's the difference between m68k-coff and m68k-elf ABI?

["Alex Holland" <alexh at stellarwinds dot com>]

I recently built 68k cross-compilers for coff, a.out, and elf output formats hosted under Cygwin. I started with ELF because  it seemed to be the most capable (e.g. there seemed to be more compiler extensions that only worked with ELF,  it was completely flexible in allowing one to create, name, and locate sections, etc.).  It also seems to be evolving into the preferred format of most tool chains for 32 bit processors. However, I realized too late that no ICE or other debug tool that I could find (except for GDB) supported this format for the 68K. However, all debug tools that I looked at supported it for more modern processors. Next, I went to COFF and did not notice much difference for what I was doing. Almost the same linker script worked and I had to change my startup code a little. However, I am using my own startup code and (simplified) C runtime libraries. I am using libgcc. I also tried a.out because one particular ICE only supported this format. However, this format caused me lots of grief. It gives you no capability to name and locate special sections. I had to change my linker script and my startup code significantly, and source level debugging was crippled.

 

Also, I have not had much luck using objcopy  to go from ELF to COFF, a.out, or IEEE695. The copy might complete, but the result would not be accepted by the particular ICE I was testing, while a direct output of the compiler generally would. 

 

Alex

----- Original Message -----

From: clifftsai

To: crossgcc

Sent: Monday, January 15, 2001 7:54 PM

Subject: What's the difference between m68k-coff and m68k-elf ABI?

Hi:

    When I build the m68k cross development according

     Instructions from Cygnus's Website.The instrucions tell

    us to build m68k tool as m68k-coff.

    But when I look into the glibc/sysdeps/m68k/elf.

    The Start.s is for m68k-elf ABI.Why?How about Start.s

    for coff.

    And if I use m68k-coff or m68k-arm,what should I modified?

   

    Thanks

    Cliff