Re: [MiNT] Binutils 2.18 + GCC 4.2.3

[Vincent Rivière <vincent.riviere@freesbee.fr>]

Alan Hourihane wrote:
> > > I get this building gcc with the above patches.....
> > >
> > > /ISO/Atari/GCC/gcc-4.2.3-mint-native/m68k-atari-mint/mshort/libstdc
> > > ++-v3/include/iosfwd:71: warning: alignment of
> > > 'std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char>
> > > > ::_ZTVSt15basic_stringbufIcSt11char_traitsIcESaIcEE' is greater than
> > > maximum object file alignment.  Using 2
> > This warning is issued when the alignment requested by the C compiler (probably ".align 
> > 4") is not supported by the assembler.
> > You have patched GCC, but you probably forgot to patch the binutils (or maybe it needs 
> > additional patching). The binutils "patch" is actually to use the original version 
> > (unpatched) of bfd/cpu-m68k.c
>
> Oh, this is on mshort, so is it to be expected ?

Hmm... I don't think mshort should produce such warning.
Note that mshort is a concept inside GCC, the binutils know nothing about that.

Here is an example on m68k-linux :

$ cat b.s
        nop
        .align  4
        rts

$ m68k-linux-as b.s -o b.o
$ m68k-linux-objdump -h b.o

b.o:     file format elf32-m68k

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00000006  00000000  00000000  00000034  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  1 .data         00000000  00000000  00000000  0000003c  2**2
                  CONTENTS, ALLOC, LOAD, DATA
  2 .bss          00000000  00000000  00000000  0000003c  2**2
                  ALLOC

We can see the .o alignment is 2**2 (4)

$ m68k-linux-objdump -d b.o

b.o:     file format elf32-m68k

Disassembly of section .text:

00000000 <.text>:
   0:   4e71            nop
   2:   0000 4e75       orib #117,%d0

We can see that rts (4e75) is aligned on a 4 byte boundary (offset 4)

Try this example with your binutils.
Do you get the same result ?

PS: This example is stupid, because .align inserts a word with value 0 so an instruction 
"ori.b" is generated and combined with the rts value

--
Vincent Rivière