diff --git a/src/ia64/Gstep.c b/src/ia64/Gstep.c
new file mode 100644
index 00000000..a266f00b
--- /dev/null
+++ b/src/ia64/Gstep.c
@@ -0,0 +1,132 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2001-2002 Hewlett-Packard Co
+	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include "offsets.h"
+#include "rse.h"
+#include "unwind_i.h"
+
+static inline int
+update_frame_state (struct ia64_cursor *c)
+{
+  unw_word_t prev_ip, prev_sp, prev_bsp, ip, pr, num_regs, cfm;
+  int ret;
+
+  prev_ip = c->ip;
+  prev_sp = c->sp;
+  prev_bsp = c->bsp;
+
+  c->cfm_loc = c->pfs_loc;
+
+  num_regs = 0;
+  if (c->is_signal_frame)
+    {
+      ret = ia64_get (c, c->sp + 0x10 + SIGFRAME_ARG2_OFF, &c->sigcontext_loc);
+      debug (100, "%s: sigcontext_loc=%lx (ret=%d)\n",
+	     __FUNCTION__, c->sigcontext_loc, ret);
+      if (ret < 0)
+	return ret;
+
+      if (c->ip_loc == c->sigcontext_loc + SIGCONTEXT_BR_OFF + 0*8)
+	{
+	  /* Earlier kernels (before 2.4.19 and 2.5.10) had buggy
+	     unwind info for sigtramp.  Fix it up here.  */
+	  c->ip_loc  = (c->sigcontext_loc + SIGCONTEXT_IP_OFF);
+	  c->cfm_loc = (c->sigcontext_loc + SIGCONTEXT_CFM_OFF);
+	}
+
+      /* do what can't be described by unwind directives: */
+      c->pfs_loc = (c->sigcontext_loc + SIGCONTEXT_AR_PFS_OFF);
+
+      ret = ia64_get (c, c->cfm_loc, &cfm);
+      if (ret < 0)
+	return ret;
+
+      num_regs = cfm & 0x7f;		/* size of frame */
+    }
+  else
+    {
+      ret = ia64_get (c, c->cfm_loc, &cfm);
+      if (ret < 0)
+	return ret;
+      num_regs = (cfm >> 7) & 0x7f;	/* size of locals */
+    }
+  c->bsp = ia64_rse_skip_regs (c->bsp, -num_regs);
+
+  /* update the IP cache: */
+  ret = ia64_get (c, c->ip_loc, &ip);
+  if (ret < 0)
+    return ret;
+  c->ip = ip;
+
+  if ((ip & 0xc) != 0)
+    {
+      /* don't let obviously bad addresses pollute the cache */
+      debug (1, "%s: rejecting bad ip=0x%lx\n",  __FUNCTION__, (long) c->ip);
+      return -UNW_EINVALIDIP;
+    }
+  if (ip == 0)
+    /* end of frame-chain reached */
+    return 0;
+
+  pr = c->pr;
+  c->sp = c->psp;
+  c->is_signal_frame = 0;
+
+  if (c->ip == prev_ip && c->sp == prev_sp && c->bsp == prev_bsp)
+    {
+      dprintf ("%s: ip, sp, and bsp unchanged; stopping here (ip=0x%lx)\n",
+	       __FUNCTION__, (long) ip);
+      return -UNW_EBADFRAME;
+    }
+
+  /* as we unwind, the saved ar.unat becomes the primary unat: */
+  c->pri_unat_loc = c->unat_loc;
+
+  /* restore the predicates: */
+  ret = ia64_get (c, c->pr_loc, &c->pr);
+  if (ret < 0)
+    return ret;
+
+  c->pi_valid = 0;
+  return 0;
+}
+
+
+int
+unw_step (unw_cursor_t *cursor)
+{
+  struct ia64_cursor *c = (struct ia64_cursor *) cursor;
+  int ret;
+
+  ret = ia64_find_save_locs (c);
+  if (ret < 0)
+    return ret;
+
+  ret = update_frame_state (c);
+  if (ret < 0)
+    return ret;
+
+  return (c->ip == 0) ? 0 : 1;
+}