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Re: [RFC] mips-tdep.c: pseudo-register -> raw register sign extension
On Thu, 9 Dec 2010 12:19:00 +0100 (CET)
Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> > + LONGEST regval = extract_signed_integer (buf, 4, byte_order);
> > + store_signed_integer (buf8, 8, byte_order, regval);
> > + regcache_raw_write (regcache, rawnum, buf8);
>
> How about using regcache_raw_write_signed() here? I think that
> simplifies the code enough to change mips_pseudo_register_read() to
> use regcache_raw_read_signed() and get rid of the explicit endian-ness
> check as well.
I like this suggestion. See below for a revised patch...
Kevin
* mips-tdep.c (mips_pseudo_register_write): Sign extend 32-bit
cooked values that are being transferred to 64-bit raw registers.
(mips_pseudo_register_read): Revise to preserve symmetry with
mips_pseudo_register_write().
Index: mips-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/mips-tdep.c,v
retrieving revision 1.508
diff -u -p -r1.508 mips-tdep.c
--- mips-tdep.c 28 Nov 2010 04:31:24 -0000 1.508
+++ mips-tdep.c 9 Dec 2010 23:03:02 -0000
@@ -559,11 +559,15 @@ mips_pseudo_register_read (struct gdbarc
else if (register_size (gdbarch, rawnum) >
register_size (gdbarch, cookednum))
{
- if (gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p
- || gdbarch_byte_order (gdbarch) == BFD_ENDIAN_LITTLE)
+ if (gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p)
regcache_raw_read_part (regcache, rawnum, 0, 4, buf);
else
- regcache_raw_read_part (regcache, rawnum, 4, 4, buf);
+ {
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ LONGEST regval;
+ regcache_raw_read_signed (regcache, rawnum, ®val);
+ store_signed_integer (buf, 4, byte_order, regval);
+ }
}
else
internal_error (__FILE__, __LINE__, _("bad register size"));
@@ -582,11 +586,17 @@ mips_pseudo_register_write (struct gdbar
else if (register_size (gdbarch, rawnum) >
register_size (gdbarch, cookednum))
{
- if (gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p
- || gdbarch_byte_order (gdbarch) == BFD_ENDIAN_LITTLE)
+ if (gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p)
regcache_raw_write_part (regcache, rawnum, 0, 4, buf);
else
- regcache_raw_write_part (regcache, rawnum, 4, 4, buf);
+ {
+ /* Sign extend the shortened version of the register prior
+ to placing it in the raw register. This is required for
+ some mips64 parts in order to avoid unpredictable behavior. */
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ LONGEST regval = extract_signed_integer (buf, 4, byte_order);
+ regcache_raw_write_signed (regcache, rawnum, regval);
+ }
}
else
internal_error (__FILE__, __LINE__, _("bad register size"));