Index: src/libcfa/Makefile.am
===================================================================
--- src/libcfa/Makefile.am	(revision 9129a848d87bdbb3434b3db7693cba174b561aae)
+++ src/libcfa/Makefile.am	(revision 8e5724eb6690c6626d637781fe0055e8dde51853)
@@ -53,5 +53,17 @@
 	 ${AM_V_GEN}@BACKEND_CC@ @CFA_FLAGS@ -c -o $@ $<
 
-CFLAGS = -quiet -no-include-stdhdr -g -Wall -Wno-unused-function @CFA_FLAGS@ -B${abs_top_srcdir}/src/driver -XCFA -t # TEMPORARY: does not build with -O2
+CFLAGS = \
+	-quiet \
+	-no-include-stdhdr \
+	-g \
+	-Wall \
+	-Wno-unused-function \
+	@CFA_FLAGS@ \
+	-B${abs_top_srcdir}/src/driver \
+	-XCFA \
+	-t \
+	-D__CFA_DEBUG__ \
+	-I${abs_top_srcdir}/src/libcfa/libhdr \
+	# TEMPORARY: does not build with -O2
 CC = ${abs_top_srcdir}/src/driver/cfa
 
@@ -66,5 +78,5 @@
 ${libobjs} : ${abs_top_srcdir}/src/driver/cfa-cpp ${cfalib_DATA} # add dependency to cfa-cpp so all libraries are rebuilt with new translator
 
-libcfa_a_SOURCES = libcfa-prelude.c ${headers:=.c}
+libcfa_a_SOURCES = libcfa-prelude.c ${headers:=.c} concurrency/CtxSwitch-x86_64.S
 
 stdhdr = ${shell echo stdhdr/*}
Index: src/libcfa/Makefile.in
===================================================================
--- src/libcfa/Makefile.in	(revision 9129a848d87bdbb3434b3db7693cba174b561aae)
+++ src/libcfa/Makefile.in	(revision 8e5724eb6690c6626d637781fe0055e8dde51853)
@@ -94,5 +94,6 @@
 	rational.$(OBJEXT) assert.$(OBJEXT) \
 	containers/vector.$(OBJEXT) concurrency/threads.$(OBJEXT)
-am_libcfa_a_OBJECTS = libcfa-prelude.$(OBJEXT) $(am__objects_1)
+am_libcfa_a_OBJECTS = libcfa-prelude.$(OBJEXT) $(am__objects_1) \
+	concurrency/CtxSwitch-x86_64.$(OBJEXT)
 libcfa_a_OBJECTS = $(am_libcfa_a_OBJECTS)
 DEFAULT_INCLUDES = -I.@am__isrc@ -I$(top_builddir)
@@ -100,4 +101,9 @@
 am__depfiles_maybe = depfiles
 am__mv = mv -f
+CPPASCOMPILE = $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) \
+	$(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS)
+AM_V_CPPAS = $(am__v_CPPAS_@AM_V@)
+am__v_CPPAS_ = $(am__v_CPPAS_@AM_DEFAULT_V@)
+am__v_CPPAS_0 = @echo "  CPPAS " $@;
 COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
 	$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
@@ -130,4 +136,7 @@
 BACKEND_CC = @BACKEND_CC@
 CC = ${abs_top_srcdir}/src/driver/cfa
+CCAS = @CCAS@
+CCASDEPMODE = @CCASDEPMODE@
+CCASFLAGS = @CCASFLAGS@
 CCDEPMODE = @CCDEPMODE@
 CFA_BACKEND_CC = @CFA_BACKEND_CC@
@@ -137,5 +146,18 @@
 CFA_LIBDIR = @CFA_LIBDIR@
 CFA_PREFIX = @CFA_PREFIX@
-CFLAGS = -quiet -no-include-stdhdr -g -Wall -Wno-unused-function @CFA_FLAGS@ -B${abs_top_srcdir}/src/driver -XCFA -t # TEMPORARY: does not build with -O2
+CFLAGS = \
+	-quiet \
+	-no-include-stdhdr \
+	-g \
+	-Wall \
+	-Wno-unused-function \
+	@CFA_FLAGS@ \
+	-B${abs_top_srcdir}/src/driver \
+	-XCFA \
+	-t \
+	-D__CFA_DEBUG__ \
+	-I${abs_top_srcdir}/src/libcfa/libhdr \
+	# TEMPORARY: does not build with -O2
+
 CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
@@ -238,5 +260,5 @@
 runtimehdrs = concurrency
 libobjs = ${headers:=.o}
-libcfa_a_SOURCES = libcfa-prelude.c ${headers:=.c}
+libcfa_a_SOURCES = libcfa-prelude.c ${headers:=.c} concurrency/CtxSwitch-x86_64.S
 stdhdr = ${shell echo stdhdr/*}
 nobase_include_HEADERS = ${headers} ${stdhdr}
@@ -245,5 +267,5 @@
 
 .SUFFIXES:
-.SUFFIXES: .c .o .obj
+.SUFFIXES: .S .c .o .obj
 $(srcdir)/Makefile.in: @MAINTAINER_MODE_TRUE@ $(srcdir)/Makefile.am  $(am__configure_deps)
 	@for dep in $?; do \
@@ -322,4 +344,6 @@
 concurrency/threads.$(OBJEXT): concurrency/$(am__dirstamp) \
 	concurrency/$(DEPDIR)/$(am__dirstamp)
+concurrency/CtxSwitch-x86_64.$(OBJEXT): concurrency/$(am__dirstamp) \
+	concurrency/$(DEPDIR)/$(am__dirstamp)
 libcfa.a: $(libcfa_a_OBJECTS) $(libcfa_a_DEPENDENCIES) $(EXTRA_libcfa_a_DEPENDENCIES) 
 	$(AM_V_at)-rm -f libcfa.a
@@ -329,4 +353,5 @@
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
+	-rm -f concurrency/CtxSwitch-x86_64.$(OBJEXT)
 	-rm -f concurrency/threads.$(OBJEXT)
 	-rm -f containers/vector.$(OBJEXT)
@@ -344,6 +369,23 @@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/rational.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/stdlib.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/CtxSwitch-x86_64.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/threads.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@containers/$(DEPDIR)/vector.Po@am__quote@
+
+.S.o:
+@am__fastdepCCAS_TRUE@	$(AM_V_CPPAS)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.o$$||'`;\
+@am__fastdepCCAS_TRUE@	$(CPPASCOMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\
+@am__fastdepCCAS_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Po
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	DEPDIR=$(DEPDIR) $(CCASDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS@am__nodep@)$(CPPASCOMPILE) -c -o $@ $<
+
+.S.obj:
+@am__fastdepCCAS_TRUE@	$(AM_V_CPPAS)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.obj$$||'`;\
+@am__fastdepCCAS_TRUE@	$(CPPASCOMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ `$(CYGPATH_W) '$<'` &&\
+@am__fastdepCCAS_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Po
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	DEPDIR=$(DEPDIR) $(CCASDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS@am__nodep@)$(CPPASCOMPILE) -c -o $@ `$(CYGPATH_W) '$<'`
 
 .c.o: