This is the mail archive of the
binutils@sourceware.org
mailing list for the binutils project.
Re: [PATCH] Fix sign-extended immediates for SH on 64-bit host
On Sat, Aug 29, 2009 at 09:43:03AM +0900, Kaz Kojima wrote:
> Matt Fleming <matt@console-pimps.org> wrote:
> > it appears that the SH backend for gas has a bug in it that is exposed
> > when using a cross-compiled toolchain that is built on a 64-bit host. As
> > an example, the assembler does not interpret the immediate constant
> > 0xfffffff0 as a negative value when run on a 64-bit machine, rather it
> > is zero-extended. The constant is correctly recognised as a negative
> > integer on a 32-bit machine.
> >
> > The attached patches introduce two new macros, SEXT and TRUNC to
> > sign-extend and truncate a long, respectively. Using these macros allows
> > us to obtain the same result from using sign-extended immediates on both
> > 32-bit and 64-bit hosts.
>
> Thanks for pointing this out. The intension of your change
> is fine, though it's a bit overkill to introduce 2 macros for
> this and it would be better to put the comment at md_apply_fix
> itself. Could the attached one liner work for 64-bit host?
> Testing patch looks OK.
>
> Regards,
> kaz
> --
> * config/tc-sh.c (md_apply_fix): Extend sign of the offset value
> for 64-bit host.
>
> --- ORIG/src/gas/config/tc-sh.c 2008-09-12 09:01:35.000000000 +0900
> +++ src/gas/config/tc-sh.c 2009-08-29 09:30:53.000000000 +0900
> @@ -4183,6 +4183,9 @@ md_apply_fix (fixS *fixP, valueT *valP,
> val = ((val >> shift)
> | ((long) -1 & ~ ((long) -1 >> shift)));
> }
> +
> + /* Extend sign for 64-bit host. */
> + val = ((val & 0xffffffff) ^ 0x80000000) - 0x80000000;
> if (max != 0 && (val < min || val > max))
> as_bad_where (fixP->fx_file, fixP->fx_line, _("offset out of range"));
> else if (max != 0)
Yep, this one works OK. The reason I used the macros was in anticipation
of there being other related bugs in the assembler ;-) Though I admit, I
haven't looked for any others.