diff --git a/libsrc/atari/Makefile b/libsrc/atari/Makefile
index c66d9f41d..121c4fce4 100644
--- a/libsrc/atari/Makefile
+++ b/libsrc/atari/Makefile
@@ -21,7 +21,7 @@ S_OBJS = crt0.o kbhit.o conio.o clrscr.o cputc.o ctype.o chline.o cvline.o \
 	 color.o gotoxy.o cclear.o revers.o readjoy.o break.o where.o write.o \
 	 gotox.o gotoy.o savevec.o rwcommon.o cgetc.o read.o getargs.o close.o \
 	 open.o oserror.o fdtable.o setcolor.o scroll.o mul40.o graphuse.o \
-	 ostype.o
+	 ostype.o clock.o
 
 all:	$(C_OBJS) $(S_OBJS)
 
diff --git a/libsrc/atari/clock.s b/libsrc/atari/clock.s
new file mode 100644
index 000000000..f4bda8469
--- /dev/null
+++ b/libsrc/atari/clock.s
@@ -0,0 +1,42 @@
+;
+; Ullrich von Bassewitz, 25.07.2000
+;
+; Implemented using information from Sidney Cadot <sidney@janis.pds.twi.tudelft.nl
+;
+; clock_t clock (void);
+; unsigned _clocks_per_sec (void);
+;
+
+      	.export	       	_clock, __clocks_per_sec
+	.importzp	sreg
+
+	.include	"atari.inc"
+
+
+.proc	_clock
+
+	lda	#0  	      	; Byte 3 is always zero
+       	sta    	sreg+1
+	php			; Save current I flag value
+	cli			; Disable interrupts
+	lda	RTCLOK		; Read clock
+	ldx	RTCLOK+1
+	ldy	RTCLOK+2
+	plp			; Restore old I bit
+	rts
+
+.endproc
+
+
+.proc	__clocks_per_sec
+
+	lda	#50		; Assume PAL
+	ldx	PAL
+	beq	@L1
+	ldx	#0
+	lda	#60
+@L1:	rts
+
+.endproc
+
+