Re: Getting Closer

[Kai Ruottu <kai dot ruottu at luukku dot com>]

Mark Palmerino wrote:
> 
> Hi Kai,
> 
> Continuing from earlier, I am working on your suggestion to see if I can
> find what is different between the windows version and the unix version.
> 
> The next step I thought worth taking is to bring over the libc.a, libbcc.a
> and libgcc.a from the windows side and use them as arguments to the linker.
> I did that and put them in the directory that the hello.c file is in and
> here is the ld command which I used:
> 
> m68k-coff-ld -v -o $FN.cof \
>   -L. \
>    $FN.o -lc -lbcc -lgcc -T rm_rom.ld -M > $FN.map

 The GNU ld does things in the order you command it to do... Here is my guess
about what it would do:

 1. link your $FN.o
 2. scan the libs
 3. look at the linker script etc.

 You can easily see what it REALLY does by substituting the '-v' with '-verbose'.

> Where $FN is 'hello'.  When I execute that command, I get:
> 
> ./libc.a(exit.o)(.text+0x52):exit.c: undefined reference to `_exit'
> ./libc.a(sbrkr.o)(.text+0x12):sbrkr.c: undefined reference to `sbrk'
> ./libc.a(makebuf.o)(.text+0xdc):makebuf.c: undefined reference to `isatty'
> ./libc.a(readr.o)(.text+0x1a):readr.c: undefined reference to `read'
> ./libc.a(lseekr.o)(.text+0x1a):lseekr.c: undefined reference to `lseek'
> ./libc.a(writer.o)(.text+0x1a):writer.c: undefined reference to `write'
> ./libc.a(closer.o)(.text+0x12):closer.c: undefined reference to `close'
> ./libc.a(fstatr.o)(.text+0x16):fstatr.c: undefined reference to `fstat'
> 
> This seems odd since all of these are declared in the libbcc.a library in
> the directory. Here is the output from ar:
> 
> m68k-coff-ar tv libbcc.a
> rw-rw-r-- 500/500   4440 Aug 13 22:23 1999 fstat.o
> rw-rw-r-- 500/500   2212 Aug 13 22:23 1999 getpid.o
> rw-rw-r-- 500/500   2234 Aug 13 22:23 1999 isatty.o
> rw-rw-r-- 500/500   2322 Aug 13 22:23 1999 kill.o

 This doesn't tell anything, but the 'm68k-coff-nm libgcc.a | grep exit'
for the first undefined would have told something... Of couse it would
be unexpected if the 'libc.a' and 'libbcc.a' weren't in sync what becomes
to the symbol names...

> I don't quite know where to go from here. Do you have any suggestions?

 Perhaps the 'libbcc.a' wasn't indexed by 'm68k-coff-ranlib', you could
try that or put a 'libbcc.a' instead of '-lbcc' into the command line...

 But checking with 'm68k-coff-nm' the symbol name in 'libc.a', being there
as undefined, 'U', and in 'libbcc.a', being there as defined, 'T' is the
first thing to do, like here for '_exit' :

E:\usr\local\m68k-coff\lib>..\bin\nm libc.a | grep exit
         U _exit
atexit.o:
00000000 T atexit
exit.o:
         U _exit
00000000 T exit

E:\usr\local\m68k-coff\lib>..\bin\nm libbcc.a | grep exit
         U _exit
00000000 T _exit

 The names must be same. Here we can see that probably the 'exit.o' in
'libc.a' has the function 'exit()' which calls the function '_exit()'
and this function is somewhere in 'libbcc.a'. Using '...| more' and
browsing/searching for '_exit' would tell in which compiled object
the function is... In 'libbcc.a' there is another function calling the
'_exit()' and in 'libc.a' too...

Cheers, Kai


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