diff -rNu gdb.tmp/i387-float-reverse.c gdb.arch/i387-float-reverse.c
--- gdb.tmp/i387-float-reverse.c	1969-12-31 16:00:00.000000000 -0800
+++ gdb.arch/i387-float-reverse.c	2009-07-11 17:16:56.000000000 -0700
@@ -0,0 +1,30 @@
+/* Reverse debugging of floating point registers.
+
+   Copyright 2009, Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int main (void)
+{
+  int i = 0;	/* BEGIN I387-FLOAT-REVERSE */
+
+  asm ("fldz");	/* test st0 register */
+  asm ("fld1");
+  asm ("nop");
+
+  return i;	/* END I387-FLOAT-REVERSE */
+}
+
diff -rNu gdb.tmp/i387-float-reverse.exp gdb.arch/i387-float-reverse.exp
--- gdb.tmp/i387-float-reverse.exp	1969-12-31 16:00:00.000000000 -0800
+++ gdb.arch/i387-float-reverse.exp	2009-07-11 17:30:03.000000000 -0700
@@ -0,0 +1,83 @@
+# Copyright 2009 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+if $tracelevel {
+    strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+if ![istarget "i?86-*linux*"] then {
+    verbose "Skipping i387 reverse float tests."
+    return
+}
+
+set testfile "i387-float-reverse"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+# some targets have leading underscores on assembly symbols.
+# TODO: detect this automatically
+set additional_flags ""
+if [istarget "i?86-*-cygwin*"] then {
+  set additional_flags "additional_flags=-DSYMBOL_PREFIX=\"_\""
+}
+
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable [list debug $additional_flags]] != "" } {
+    untested i387-float-reverse
+    return -1
+}
+
+# Get things started.
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+runto main
+
+# Record to end of main
+
+set location [gdb_get_line_number "END I387-FLOAT-REVERSE"]
+gdb_test "record" "" "Turn on process record"
+gdb_test "until $location" ".*/$srcfile:$location.*" \
+    "record to end of main"
+
+# Now rewind to beginning so we can begin testing.
+
+set location [gdb_get_line_number "BEGIN I387-FLOAT-REVERSE"]
+gdb_test "set exec-dir reverse" "" "set reverse direction"
+gdb_test "until $location" ".*/$srcfile:$location.*" \
+    "rewind to beginning of main"
+gdb_test "set exec-dir forward" "" "set forward direction"
+
+# Test st0 register
+
+set location [gdb_get_line_number "test st0 register"]
+gdb_test "until $location" ".*/$srcfile:$location.*asm.*fldz.*" \
+    "begin test st0"
+gdb_test "stepi" "asm.*fld1.*"            "set st0 == 0"
+gdb_test "info register st0" "st0 *0\t.*" "verify st0 == 0"
+gdb_test "stepi" "asm.*nop.*"             "set st0 == 1"
+gdb_test "info register st0" "st0 *1\t.*" "verify st0 == 1"
+
+# Now step backward, and check that st0 value reverts to zero.
+
+gdb_test "reverse-stepi" "asm.*fld1.*"    "undo set st0 == 1"
+gdb_test "info register st0" "st0 *0\t.*" "verify st0 == 0 again"
+