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Re: [RFA] legacy_[read/write]_register_gen
- From: Michael Snyder <msnyder at redhat dot com>
- To: Andrew Cagney <ac131313 at cygnus dot com>
- Cc: Michael Snyder <msnyder at cygnus dot com>, gdb-patches at sources dot redhat dot com, cagney at redhat dot com
- Date: Tue, 29 Jan 2002 10:39:04 -0800
- Subject: Re: [RFA] legacy_[read/write]_register_gen
- Organization: Red Hat, Inc.
- References: <200201290102.g0T12Uk24471@reddwarf.cygnus.com> <3C5614AF.4050809@cygnus.com>
Andrew Cagney wrote:
>
> > These two functions need to be able to read/write
> > a pseudo-register as well as a real register.
> >
> > 2002-01-28 Michael Snyder <msnyder@redhat.com>
> >
> > * regcache.c (legacy_read_register_gen): Need to be able to
> > read pseudo-register as well as real register.
> > (legacy_write_register_gen): Ditto.
>
> Michael,
>
> When is this occuring? Dig dig, I've a similar patch sitting in my
> sand-pit so, hmm, I've also seen it but don't remember why :-(
>
> Andrew
Simplest case -- say you want to have a pseudo-register that
mirrors the contents of a real register.
static void
my_fetch_pseudo_register (int regnum)
{
if (regnum == MY_MIRROR_REGNUM)
{
char buf[REGISTER_SIZE];
regcache_read (MY_REAL_REGNUM, buf);
regcache_write (MY_MIRROR_REGNUM, buf);
}
}
You can't do that unles legacy_write_register_bytes can address
the regcache location of your pseudo-register.
> > Index: regcache.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/regcache.c,v
> > retrieving revision 1.30
> > diff -c -3 -p -r1.30 regcache.c
> > *** regcache.c 2002/01/15 02:06:46 1.30
> > --- regcache.c 2002/01/29 01:02:29
> > *************** legacy_read_register_gen (int regnum, ch
> > *** 310,316 ****
> > void
> > regcache_read (int rawnum, char *buf)
> > {
> > ! gdb_assert (rawnum >= 0 && rawnum < NUM_REGS);
> > /* For moment, just use underlying legacy code. Ulgh!!! */
> > legacy_read_register_gen (rawnum, buf);
> > }
> > --- 310,316 ----
> > void
> > regcache_read (int rawnum, char *buf)
> > {
> > ! gdb_assert (rawnum >= 0 && rawnum < (NUM_REGS + NUM_PSEUDO_REGS));
> > /* For moment, just use underlying legacy code. Ulgh!!! */
> > legacy_read_register_gen (rawnum, buf);
> > }
> > *************** legacy_write_register_gen (int regnum, c
> > *** 369,375 ****
> > void
> > regcache_write (int rawnum, char *buf)
> > {
> > ! gdb_assert (rawnum >= 0 && rawnum < NUM_REGS);
> > /* For moment, just use underlying legacy code. Ulgh!!! */
> > legacy_write_register_gen (rawnum, buf);
> > }
> > --- 369,375 ----
> > void
> > regcache_write (int rawnum, char *buf)
> > {
> > ! gdb_assert (rawnum >= 0 && rawnum < (NUM_REGS + NUM_PSEUDO_REGS));
> > /* For moment, just use underlying legacy code. Ulgh!!! */
> > legacy_write_register_gen (rawnum, buf);
> > }
> >
> >
> >