Re: Selecting from several m68k libc.a

[Jeff Johnston <jjohnstn at redhat dot com>]

Vitus Jensen wrote:
> Hej!
>
> In my build there are several libc.a (and libm.a, libhwdos.a) created and
> installed:
>
> T:\C\coldfire\gcc-m68k\m68k-coff\lib\libc.a
> T:\C\coldfire\gcc-m68k\m68k-coff\lib\m5200\libc.a
> T:\C\coldfire\gcc-m68k\m68k-coff\lib\m68000\libc.a
> T:\C\coldfire\gcc-m68k\m68k-coff\lib\mcpu32\libc.a
> T:\C\coldfire\gcc-m68k\m68k-coff\lib\msoft-float\libc.a
>
> All different :-(
>
> Using the following linker commands:
> STARTUP(hwdos-crt0.o)
> OUTPUT_ARCH(m68k)
> OUTPUT_FORMAT(srec)
> SEARCH_DIR(m68000)
> SEARCH_DIR(m68k)
> GROUP(-lc -lhwdos)
>
> T:\C\coldfire\gcc-m68k\m68k-coff\lib\libc.a is used.  But this libc.a seems
> to be created for a different MC68000 brand than DragonBall, I ran into a
> "tst a1" opcode which isn't supported.
>
> So I would like to try other libcs.  Something compiled for the original
> MC68000.  Which one is it?  And how do I tell the linker to use it?
>
> Thank you for your help,
>     Vitus
>
> PS: simply copying the file is no solution :-((

The way this is supposed to work is that you specify compile options that the 
compiler uses to select the proper library directory.  You should see a bunch of 
other subdirectories off of your gcc-m68k\m68k-coff directory.

If you run the cross-compiler with the option -print-multi-lib you will see a 
list of compiler options and to what directory they match up with.  You can also 
specify compiler options and ask it to tell you what subdirectory it is going to 
fish out of using the -print-multi-directory option.  If the option to get code 
for the DragonBall is not in the list somewhere, you are going to have to edit 
and rebuild the compiler to add it and then rebuild newlib.  Newlib uses the 
-print-multi-lib option to determine the permutations it will build the library 
with.

If the option is part of the To do the compile with link is easiest.  For 
example, if the special DragonBall option was -mcpu=dragonball then you simply 
do a compile with link specifying the -mcpu=dragonball option and the -Tyour.ld 
option.  When the compiler and library are installed in the same location, the 
compiler knows how to set up the directory to get the library that has been 
built with the same options.  If you attempt to link as a separate step, then 
you have to manually specify where the library is using the -L option or its 
script equivalent: SEARCH_DIR.  The same applies if you have built the library 
separate from the compiler. In either case, you need to know the subdirectory of 
the newlib install directory to get the libraries from which is more cumbersome.

-- Jeff J.