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Patch: Fix ftag error when it is restored from fxsave in gdbserver on x86
- From: "Qunying Pan" <qpan at mvista dot com>
- To: <gdb-patches at sourceware dot org>
- Cc: <qunyingpan at gmail dot com>
- Date: Tue, 1 Nov 2005 09:10:57 -0800
- Subject: Patch: Fix ftag error when it is restored from fxsave in gdbserver on x86
Hello,
Sent out to gdb-patches@sources.redhat.com yesterday, but did not get
through I guess. Try again to gdb-patches@sourceware.org.
This patch fixes ftag error when it is restored from fxsave in gdbserver
on x86. Acceptable?
Thanks,
Qunying
--------------------
The testcase is:
typedef long double doublest;
doublest
add_doublest (doublest u, doublest v)
{
return u + v;
}
int
main ()
{
doublest z = 0.0;
doublest x=1.0,y=2.0;
z = add_doublest(x, y);
printf("%Lf, %Lf %Lf\n", x, y, z);
return 0;
}
When debug with gdbserver, and set breakpoint at add_doublest in
cross-gdb, the output z will be set to nan instead of the expected
output 3.0.
The patch is:
2005-10-31 Qunying Pan <qpan@mvista.com>
* gdbserver/i387-fp.c (i387_fxsave_to_cache): Fixing ftag error when
it is restored from fxsave
diff -urNp src/gdb/gdbserver.orig/i387-fp.c src/gdb/gdbserver/i387-fp.c
--- src/gdb/gdbserver.orig/i387-fp.c 2005-06-12 18:59:22.000000000
-0700
+++ src/gdb/gdbserver/i387-fp.c 2005-10-31 16:53:29.000000000 -0800
@@ -247,7 +247,7 @@ i387_fxsave_to_cache (const void *buf)
int i, top;
int st0_regnum = find_regno ("st0");
int xmm0_regnum = find_regno ("xmm0");
- unsigned long val;
+ unsigned long val, val2;
for (i = 0; i < 8; i++)
supply_register (i + st0_regnum, ((char *) &fp->st_space[0]) + i *
16);
@@ -267,7 +267,8 @@ i387_fxsave_to_cache (const void *buf)
/* Generate the form of ftag data that GDB expects. */
top = (fp->fstat >> 11) & 0x7;
- val = 0;
+ val = fp->ftag;
+ val2 = 0;
for (i = 7; i >= 0; i--)
{
int tag;
@@ -275,9 +276,9 @@ i387_fxsave_to_cache (const void *buf)
tag = i387_ftag (fp, (i + 8 - top) % 8);
else
tag = 3;
- val |= tag << (2 * i);
+ val2 |= tag << (2 * i);
}
- supply_register_by_name ("ftag", &val);
+ supply_register_by_name ("ftag", &val2);
val = fp->fiseg & 0xFFFF;
supply_register_by_name ("fiseg", &val);