Re: [PATCH] Use read_memory_unsigned_integer when reading to CORE_ADDR

[Daniel Jacobowitz <drow at mvista dot com>]

On Sat, Oct 05, 2002 at 10:48:35PM -0400, Klee Dienes wrote:
> The following patch converts several instances of read_memory_integer  
> to read_memory_unsigned_integer.
> In all cases except one, the value is being read into a CORE_ADDR,  
> which will cause sign-extension lossage if read_memory_integer is used  
> with a 64-bit bfd (the final case is reading into an unsigned int, but  
> I believe the change is still correct).
> 
> 2002-10-05  Klee Dienes  <kdienes@apple.com>
> 
>         * blockframe.c (sigtramp_saved_pc): Use
>         read_memory_unsigned_integer to read a value destined for a
>         CORE_ADDR, not read_memory_integer.
>         * f-valprint.c (f77_get_dynamic_upperbound): Ditto.
>         (f77_get_dynamic_lowerbound): Ditto.
>         * symfile.c (simple_read_overlay_region_table): Ditto (this
>         function is reading to an unsigned int, not a CORE_ADDR, and is
>         commented out, but I believe reading as unsigned is still
>         correct).

Well, I'm a little concerned about this.  MIPS generally wants the
result to be sign extended; the MIPS 32-bit ABIs map onto the lowest
and highest 2G segments of the 64-bit address space, not the low 4G
segment.  Isn't there an appropriate function somewhere to read a CORE_ADDR?

Answer: Yes, there is, but it has the same problem.  You're just
extending current practice, so I don't see a problem with your patch.

Andrew, is my understanding right?  Is there some reason this isn't a
problem?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer