diff --git a/mps/src/gc.gmk b/mps/src/gc.gmk
index 2c6c1f8a0b5..6192b1ffa16 100644
--- a/mps/src/gc.gmk
+++ b/mps/src/gc.gmk
@@ -1,7 +1,7 @@
 #
 #              GENERIC BUILD.GC MAKEFILE FRAGMENT
 #
-# $HopeName: MMsrc/!gc.gmk(trunk.2)$
+# $HopeName: MMsrc/!gc.gmk(trunk.3)$
 #
 # Copyright (C) 1995 Harlequin Group, all rights reserved
 #
@@ -17,7 +17,9 @@
 #               the compiler, e.g. "-DOS_SUNOS -DARCH_SPARC -DBUILD_GCC"
 #   STD		list of sources which make up the "std" part for this platform
 #   MPM		as above for the "mpm" part
+#   MPMS	assembler sources for the "mpm" part
 #   AMC		as above for the "amc" part
+#   DW		as above for the "dw" part
 #   TESTLIB	as above for the "testlib" part
 #   LIBS	extra libraries to include in tests (usually "-lm")
 #   NOISY	if defined and non-empty, causes commands to be emitted
@@ -58,6 +60,9 @@ endif
 ifndef AMC
 error "gc.gmk: AMC not defined"
 endif
+ifndef DW
+error "gc.gmk: DW not defined"
+endif
 ifndef TESTLIB
 error "gc.gmk: TESTLIB not defined"
 endif
@@ -102,15 +107,18 @@ CFDEVEL = \
 
 # These map the source file lists onto object files and dependency files
 # in the platform/variety directory.
+# 
 # %%PART: Add a new macro which expands to the files included in the part.
 
 ifdef VARIETY
 STDOBJ = $(STD:%.c=$(PFM)/$(VARIETY)/%.o)
 STDDEP = $(STD:%.c=$(PFM)/$(VARIETY)/%.d)
-MPMOBJ = $(MPM:%.c=$(PFM)/$(VARIETY)/%.o)
+MPMOBJ = $(MPM:%.c=$(PFM)/$(VARIETY)/%.o) $(MPMS:%.s=$(PFM)/$(VARIETY)/%.o)
 MPMDEP = $(MPM:%.c=$(PFM)/$(VARIETY)/%.d)
 AMCOBJ = $(AMC:%.c=$(PFM)/$(VARIETY)/%.o)
 AMCDEP = $(AMC:%.c=$(PFM)/$(VARIETY)/%.d)
+DWOBJ = $(DW:%.c=$(PFM)/$(VARIETY)/%.o)
+DWDEP = $(DW:%.c=$(PFM)/$(VARIETY)/%.d)
 TESTLIBOBJ = $(TESTLIB:%.c=$(PFM)/$(VARIETY)/%.o)
 TESTLIBDEP = $(TESTLIB:%.c=$(PFM)/$(VARIETY)/%.d)
 endif
@@ -134,14 +142,14 @@ endif
 # "all" builds all varieties of all targets
 # %%TARGET: Add the target to the all dependencies.
 
-all: amcdev lockcov stdcover mpmstres std.a
+all: dwstress amcdev lockcov stdcover mpmstres std.a
 
 # These convenience targets allow one to type "make foo" to build target
 # foo in all varieties.
 #
 # %%TARGET: Add a pseudo-target for the new target here.
 
-amcdev lockcov stdcover mpmstres std.a: phony
+dwstress amcdev lockcov stdcover mpmstres std.a: phony
 	$(MAKE) -f $(PFM).gmk TARGET=$@ target
 
 # "clean" removes the directory containing the build results for the platform.
@@ -194,6 +202,9 @@ $(PFM)/$(VARIETY)/lockcov: $(PFM)/$(VARIETY)/lockcov.o \
 $(PFM)/$(VARIETY)/amcdev: $(PFM)/$(VARIETY)/amcdev.o \
 	$(MPMOBJ) $(STDOBJ) $(AMCOBJ) $(TESTLIBOBJ)
 
+$(PFM)/$(VARIETY)/dwstress: $(PFM)/$(VARIETY)/dwstress.o \
+	$(MPMOBJ) $(STDOBJ) $(AMCOBJ) $(DWOBJ) $(TESTLIBOBJ)
+
 $(PFM)/$(VARIETY)/std.a: $(STDOBJ)
 
 $(PFM)/$(VARIETY)/mpm.a: $(MPMOBJ)
@@ -215,6 +226,12 @@ $(PFM)/$(VARIETY)/%.o: %.c
 	test -d $(PFM)/$(VARIETY) || mkdir $(PFM)/$(VARIETY)
 	gcc $(CFLAGS) -c -o $@ $<
 
+$(PFM)/$(VARIETY)/%.o: %.s
+	$(ECHO) "$(PFM): $@"
+	test -d $(PFM) || mkdir $(PFM)
+	test -d $(PFM)/$(VARIETY) || mkdir $(PFM)/$(VARIETY)
+	gcc $(CFLAGS) -c -o $@ $<
+
 # Dependencies
 #
 # These are included into _this_ makefile (see below).  GNU make does the