diff --git a/cephes-double/makefile b/cephes-double/makefile
index a5b6212..07d5ba2 100644
--- a/cephes-double/makefile
+++ b/cephes-double/makefile
@@ -1,16 +1,17 @@
 # Double precision Cephes library
 # Makefile for unix or GCC
+# IMPORTANT: select desired assmbly language utilities for your machine type.
 
 CC = gcc
+#CC = /a/gnu/linux/gcc/xgcc -B/a/gnu/linux/gcc/ -I/a/gnu/linux/gcc/include
 #CFLAGS = -g -O2 -Wall -fno-builtin # -ffloat-store
-CFLAGS ?= -O3 -Wall -fno-builtin -fPIC
+CFLAGS = -g -O2 -Wall -fno-builtin
 AR = ar
 RANLIB = ranlib
-INCS = .
+INCS = mconf.h
 AS = as
-OUT_DIR ?= .
 
-OBJ = acosh.o airy.o asin.o asinh.o atan.o atanh.o bdtr.o beta.o \
+OBJS = acosh.o airy.o asin.o asinh.o atan.o atanh.o bdtr.o beta.o \
 btdtr.o cbrt.o chbevl.o chdtr.o clog.o cmplx.o const.o \
 cosh.o dawsn.o drand.o ei.o ellie.o ellik.o ellpe.o ellpj.o ellpk.o \
 exp.o exp10.o exp2.o expn.o expx2.o fabs.o fac.o fdtr.o \
@@ -22,18 +23,106 @@ shichi.o sici.o sin.o sindg.o sinh.o spence.o stdtr.o struve.o \
 tan.o tandg.o tanh.o unity.o yn.o zeta.o zetac.o \
 sqrt.o floor.o setprec.o mtherr.o
 
-OBJS = $(addprefix $(OUT_DIR)/,$(OBJ))
+all: libmd.a mtst dtestvec monot dcalc paranoia # stamp-timing
 
-$(OUT_DIR)/%.o: %.c
-	$(CC) $(CFLAGS) -I $(INCS) -c -o $@ $<
+stamp-timing: libmd.a mtst time-it
+	time-it "mtst > /dev/null"
+	touch stamp-timing
 
-$(OUT_DIR)/libmd.a: $(OBJS) $(INCS)
-	$(AR) rv $@ $(OBJS)
-	$(RANLIB) $@
+time-it: time-it.o
+	$(CC) -o time-it time-it.o
 
-lib: $(OUT_DIR)/libmd.a
+time-it.o: time-it.c
+	$(CC) -O2 -c time-it.c
+
+dcalc: dcalc.o libmd.a
+	$(CC) -o dcalc dcalc.o libmd.a
+#	aout2exe mtst
+
+mtst: mtst.o libmd.a
+	$(CC) -v -o mtst mtst.o libmd.a
+#	gcc -Wl,-verbose -b i486-linuxaout -v -o mtst mtst.o libmd.a
+#	coff2exe mtst
+
+mtst.o: mtst.c
+	$(CC) -O2 -Wall -c mtst.c
+
+dtestvec: dtestvec.o libmd.a
+	$(CC) -o dtestvec dtestvec.o libmd.a
+
+dtestvec.o: dtestvec.c
+	$(CC) -g -c dtestvec.c
+
+monot: monot.o libmd.a
+	$(CC) -o monot monot.o libmd.a
+
+monot.o: monot.c
+	$(CC) -g -c monot.c
+
+paranoia: paranoia.o setprec.o libmd.a
+	$(CC) -o paranoia paranoia.o setprec.o libmd.a
+
+paranoia.o: paranoia.c
+	$(CC) -Wno-implicit -c paranoia.c
+
+libmd.a: $(OBJS) $(INCS)
+# for real Unix:
+	$(AR) rv libmd.a $(OBJS)
+# for djgcc MSDOS:
+#	>libmd.rf -rv libmd.a $(OBJS)
+#	$(AR) @libmd.rf
+	$(RANLIB) libmd.a
+
+# Assembly language utilities.
+# If the following are all commented out, the C versions
+# will be used by default.
+
+# IBM PC:
+#sqrt.o: sqrt.387
+#	$(AS) -o sqrt.o sqrt.387
+#
+#floor.o: floor.387
+#	$(AS) -o floor.o floor.387
+#
+#setprec.o: setprec.387
+#	$(AS) -o setprec.o setprec.387
+
+# ELF versions for linux (no underscores)
+
+#sqrt.o: sqrtelf.387
+#	$(AS) -o sqrt.o sqrtelf.387
+
+#floor.o: floorelf.387
+#	$(AS) -o floor.o floorelf.387
+
+#setprec.o: setprelf.387
+#	$(AS) -o setprec.o setprelf.387
+
+sqrt.o: sqrtelf.amd64
+	$(AS) -o sqrt.o sqrtelf.amd64
+
+setprec.o: setprelf.amd64
+	$(AS) -o setprec.o setprelf.amd64
+
+# Motorola 68881. Caution, subroutine return conventions vary.
+#sqrt.o: sqrt.688
+#	$(AS) -o sqrt.o sqrt.688
+#
+#setprec.o: setprec.688
+#	$(AS) -o setprec.o setprec.688
+
+# SPARC:
+#sqrt.o: sqrt.spa
+#	$(AS) -o sqrt.o sqrt.spa
 
 clean:
-	rm -f $(OUT_DIR)/*.o
-	rm -f $(OUT_DIR)/libmd.a
+	rm -f *.o
+	rm -f mtst
+	rm -f paranoia
+	rm -f dcalc
+	rm -f dtestvec
+	rm -f monot
+	rm -f libmd.a
+	rm -f time-it
+	rm -f dtestvec
 
diff --git a/cephes-double/setprelf.amd64 b/cephes-double/setprelf.amd64
index d6f7d21..2954119 100644
--- a/cephes-double/setprelf.amd64
+++ b/cephes-double/setprelf.amd64
@@ -14,9 +14,9 @@ LFB0:
 	subq $8,%rsp
 	fstcw (%rsp)
 	fwait
-	movw (%rsp),%rax
-	andw $0xfcff,%rax
-	movw %rax,(%rsp)
+	movw (%rsp),%ax
+	andw $0xfcff,%ax
+	movw %ax,(%rsp)
 	fldcw (%rsp)
 	popq %rax
 	popq %rax
@@ -36,8 +36,8 @@ dprec:
 	andq $0xfcff,%rax
 /* trap on overflow */
 /*	andq $0xfcf7,%rax */
-	orw $0x200,%rax
-	movw %rax,(%rsp)
+	orw $0x200,%ax
+	movw %ax,(%rsp)
 	fldcw (%rsp)
 	popq %rax
 	popq %rax
@@ -52,8 +52,8 @@ ldprec:
 	subq $8,%rsp
 	fstcw (%rsp)
 	fwait
-	movw (%rsp),%rax
-	orw $0x300,%rax
+	movw (%rsp),%ax
+	orw $0x300,%ax
 	movq %rax,(%rsp)
 	fldcw (%rsp)
 	popq %rax