diff --git a/sim/ppc/ChangeLog b/sim/ppc/ChangeLog
index d7f31be13e..02dda8ca66 100644
--- a/sim/ppc/ChangeLog
+++ b/sim/ppc/ChangeLog
@@ -1,3 +1,18 @@
+Wed Jan 29 12:32:41 1997  Michael Meissner  <meissner@tiktok.cygnus.com>
+
+	* configure.in (sim_callback): If the gdb is post 4.16, configure
+	callback support from the common directory.
+	* configure: Regenerate.
+
+	* Makefile.in (BUILT_SRC_WO_CONFIG): Add targ-vals.{h,def} and
+	targ-map.c.
+	(GDB_OBJ): Add callback support configured in.
+	(gentmap,targ-vals.def): Build from common directory.
+	(targ-vals.h,targ-map.c): Build by running gentmap.
+	(callback.o): Build from source in common directory.
+	(targ-map.o): Add dependency.
+	(clean): Remove gentmap.
+
 Thu Jan 23 09:07:26 1997  Andrew Cagney  <cagney@kremvax.tpgi.com.au>
 
 	* hw_trace.c (hw_trace_init_data): Delete.  The trace options need
diff --git a/sim/ppc/Makefile.in b/sim/ppc/Makefile.in
index b14084e189..2917624fce 100644
--- a/sim/ppc/Makefile.in
+++ b/sim/ppc/Makefile.in
@@ -222,7 +222,8 @@ BUILT_SRC_WO_CONFIG = \
 	support.h support.c \
 	pk.h \
 	hw.h hw.c \
-	filter_host.c
+	filter_host.c \
+	targ-vals.h targ-map.c targ-vals.def
 
 BUILT_SRC = \
 	$(BUILT_SRC_WO_CONFIG) \
@@ -298,7 +299,7 @@ LIB_OBJ = \
 	options.o
 
 
-GDB_OBJ = sim_calls.o 
+GDB_OBJ = sim_calls.o @sim_callback@
 
 HW_SRC = @sim_hw_src@
 HW_OBJ = @sim_hw_obj@
@@ -383,6 +384,30 @@ itable.o: itable.c itable.h
 
 mon.o: mon.c $(CPU_H)
 
+# GDB after 4.16 expects the default_callback structure to be setup.
+# As a kludge, build the common stuff here for now.
+gentmap: ../common/gentmap.c Makefile targ-vals.def
+	$(CC_FOR_BUILD) $(BUILD_FLAGS) -I. -I../common -I$(srcdir)/../common -o gentmap $< $(BUILD_LIBS)
+
+targ-vals.def: ../common/nltvals.def
+	rm -f targ-vals.def
+	ln -s $< targ-vals.def || cp $< targ-vals.def
+
+targ-vals.h: Makefile gentmap $(srcdir)/../../move-if-change
+	rm -f tmp-vals.h
+	./gentmap -h > tmp-vals.h
+	$(srcdir)/../../move-if-change tmp-vals.h targ-vals.h
+
+targ-map.c: Makefile gentmap $(srcdir)/../../move-if-change
+	rm -f tmp-map.c
+	./gentmap -c > tmp-map.c
+	$(srcdir)/../../move-if-change tmp-map.c targ-map.c
+
+callback.o: ../common/callback.c targ-vals.h
+	$(CC) -c $(STD_CFLAGS) $<
+
+targ-map.o: targ-map.c targ-vals.h
+
 # Rebuild options whenever something changes so the date/time is up to date.
 options.o: options.c $(BASICS_H) $(CPU_H) $(IDECODE_H) $(INLINE) $(LIB_SRC) $(BUILT_SRC) config.status Makefile defines.h
 	$(CC) -c $(STD_CFLAGS) '-DOPCODE_RULES="@sim_opcode@"' '-DIGEN_FLAGS="$(IGEN_FLAGS)"' '-DDGEN_FLAGS="$(DGEN_FLAGS)"' $<
@@ -573,7 +598,7 @@ TAGS: $(BUILT_SRC)
 	etags $(srcdir)/*.h $(srcdir)/*.c $(BUILT_SRC)
 
 clean mostlyclean:
-	rm -f tmp-* *.[oasi] core psim run igen dgen $(BUILT_SRC_WO_CONFIG)
+	rm -f tmp-* *.[oasi] core psim run igen dgen $(BUILT_SRC_WO_CONFIG) gentmap
 
 distclean realclean: clean
 	rm -f TAGS Makefile config.cache config.status config.h defines.h stamp-h config.log
diff --git a/sim/ppc/configure b/sim/ppc/configure
index 5dd42c8900..3ca1f5e031 100755
--- a/sim/ppc/configure
+++ b/sim/ppc/configure
@@ -2830,6 +2830,16 @@ else
   sim_devzero=""
 fi
 
+echo $ac_n "checking for common simulator directory""... $ac_c" 1>&6
+echo "configure:2835: checking for common simulator directory" >&5
+if test -e "${srcdir}/../common/callback.c"; then
+  echo "$ac_t""yes" 1>&6
+  sim_callback="callback.o targ-map.o"
+else
+  echo "$ac_t""no" 1>&6
+  sim_callback=""
+fi
+
 
 
 
@@ -2838,7 +2848,7 @@ AR=${AR-ar}
 # Extract the first word of "ranlib", so it can be a program name with args.
 set dummy ranlib; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:2842: checking for $ac_word" >&5
+echo "configure:2852: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_RANLIB'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -2902,6 +2912,7 @@ fi
 
 
 
+
 
 
 trap '' 1 2 15
@@ -3098,6 +3109,7 @@ s%@sim_model_issue@%$sim_model_issue%g
 s%@sim_stdio@%$sim_stdio%g
 s%@sim_termio@%$sim_termio%g
 s%@sim_devzero@%$sim_devzero%g
+s%@sim_callback@%$sim_callback%g
 
 CEOF
 EOF
diff --git a/sim/ppc/configure.in b/sim/ppc/configure.in
index 1d34ab4417..daef6e2432 100644
--- a/sim/ppc/configure.in
+++ b/sim/ppc/configure.in
@@ -656,6 +656,16 @@ else
   sim_devzero=""
 fi
 
+dnl Figure out if we are in the new Cygnus tree with a common directory or not
+AC_MSG_CHECKING(for common simulator directory)
+if test -e "${srcdir}/../common/callback.c"; then
+  AC_MSG_RESULT(yes)
+  sim_callback="callback.o targ-map.o"
+else
+  AC_MSG_RESULT(no)
+  sim_callback=""
+fi
+
 AC_SUBST(CC_FOR_BUILD)
 AC_SUBST(CFLAGS)
 AC_SUBST(HDEFINES)
@@ -701,6 +711,7 @@ AC_SUBST(sim_model_issue)
 AC_SUBST(sim_stdio)
 AC_SUBST(sim_termio)
 AC_SUBST(sim_devzero)
+AC_SUBST(sim_callback)
 
 AC_OUTPUT(Makefile,
 [case x$CONFIG_HEADERS in xconfig.h:config.in) echo > stamp-h ;; esac])