Re: [Bug ld/2378] Incorrect opcode in __do_clear_bss if bss has more than 15 bytes

[Nick Clifton]

Hi Ken,

>     avr-as a.S -o a.o
>     avr-ld -m avr4 -Tdata 0x800100 -o a.elf  a.o
>     avr-objdump -d a.elf > a.lst
>     avr-ld -m avr4 -Tdata 0x800100 -o a.hex --oformat=ihex  a.o

> The list file shows both opcodes correctly, "a0 31".  But in the hex file
> the first one is wrong, "B031", while the second one is correct, "A031".
>
> The difference is that avr-ld had to do a relocation for the first one.
> Running "avr-objdump -r a.o" shows one record with type R_AVR_LO8_LDI
> relocation, value __bss_end.
>
> R_AVR_LO8_LDI is performed in binutils-2.16.1/bfd/elf32-avr.c.  It works
> correctly for the default ELF format, but fails for the IHEX format.
>
> This is progress, but I'm still stumped.

It is quite common that LD is unable to correctly translate binary file 
formats and link at the same time.  Quite a few targets suffer from this 
problem.  The simplest workaround is to perform the link first and then 
use objcopy to perform the binary translation.  ie:

  avr-ld -m avr4 -Tdata 0x800100 -o a.elf a.o
  avr-objcopy --output-target ihex a.elf a.ihex

Cheers
  Nick