[PATCH 1/2] opcodes/mips: use .word/.short for undefined instructions

[Maciej W. Rozycki]

Hi Andrew,

 In the course of reviewing outstanding upstream mailing list traffic I 
came across this change of yours.

On Thu, 3 Nov 2022, Andrew Burgess via Binutils wrote:

> diff --git a/opcodes/mips-dis.c b/opcodes/mips-dis.c
> index faeebccfc3b..1d9875f2bb0 100644
> --- a/opcodes/mips-dis.c
> +++ b/opcodes/mips-dis.c
> @@ -2515,7 +2515,10 @@ print_insn_micromips (bfd_vma memaddr, struct disassemble_info *info)
>  	}
>      }
>  
> -  infprintf (is, "0x%x", insn);
> +  if (length == 2)
> +    infprintf (is, ".short\t0x%x", insn);
> +  else
> +    infprintf (is, ".word\t0x%x", insn);

 FYI, I find this questionable as `.word' (at least with the MIPS target) 
implies natural alignment while 32-bit microMIPS encodings, valid or not, 
are not.  Also, given the endianness peculiarity (analogous to the MIPS16 
extended encodings), I think this needs to be ".short\t0x%x, 0x%x" really, 
with the instruction word split into halfwords for any reasonable meaning.  
This is already reflected in the raw hex dump of instruction streams; the 
numbers printed need to match it.

 With the naked number previously used this obviously didn't matter as it 
stood out without any attempt to pretend to have a meaning.  This is also 
the reason why I chose to keep it as it used to be since forever.

 FWIW,

  Maciej