diff --git a/Makefile b/Makefile
index fd9194a..98798d2 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,8 @@ LIBSRC = uart_init_.c uart_send_chr.c uart_send_str.c \
 	long_add__.c long_add.c \
 	long_1cpl__.c long_invert__.c long_invert.c \
 	long_sub__.c \
-       long_div__.c	long_div.c
+       long_div__.c	long_div.c  \
+       long_fill__.c long_mul__.c long_mul.c
 
 
 LIBOBJ =$(patsubst %.c,%.rel, $(LIBSRC))
diff --git a/long_add__.c b/long_add__.c
index 3a64965..b231a52 100644
--- a/long_add__.c
+++ b/long_add__.c
@@ -6,6 +6,8 @@
 static void long_add__() __naked
 {
 	__asm
+	.globl	long_add
+	.globl	long_addc
 long_add:
 	clr	c
 long_addc:
diff --git a/long_fill__.c b/long_fill__.c
new file mode 100644
index 0000000..1dd8275
--- /dev/null
+++ b/long_fill__.c
@@ -0,0 +1,19 @@
+
+
+void long_fill() __naked
+{
+	__asm
+	.globl long_fill_zero
+	.globl long_fill
+
+long_fill_zero:		
+	mov	a,#0x00
+long_fill:		
+	mov	@r0,a
+	inc	r0
+	djnz	r7,long_fill
+	ret
+	__endasm;
+}
+
+
diff --git a/long_mul.c b/long_mul.c
new file mode 100644
index 0000000..b144b24
--- /dev/null
+++ b/long_mul.c
@@ -0,0 +1,28 @@
+#include "mc8051fun.h"
+
+uint8_t long_mul(__idata uint8_t *v1, __idata uint8_t *v2,uint8_t len, __idata  uint8_t *result) __reentrant
+{
+	(void)v1; (void)v2; (void)len,(void)result;
+	__asm
+	mov	a,_bp
+	add	a,#0xfd
+	mov	r0,a
+	mov	a,@r0		; *v2
+	dec	r0
+	mov	r1,a
+	mov	a,@r0		; len
+	mov	r7,a
+	dec	r0
+	mov	a,@r0		; result
+	mov	r2,a
+	mov	r0,dpl
+	lcall	long_mul
+	mov	dpl,#0x00
+	jnc	$002
+	inc	dpl
+$002:
+	__endasm;
+}
+
+
+
diff --git a/long_mul__.c b/long_mul__.c
new file mode 100644
index 0000000..a2a64b1
--- /dev/null
+++ b/long_mul__.c
@@ -0,0 +1,55 @@
+#include "mc8051fun.h"
+
+/*
+ * val0,val1 = r0,r1
+ * r2 = result
+ * r7 = len of val0,val1
+ */
+void long_mul__()  __naked
+{
+
+	__asm
+	.globl	long_mul
+
+long_mul:
+	push	AR0
+	push 	AR7
+	mov	r0,AR2
+	lcall	long_fill_zero
+	pop	AR7
+	pop	AR0
+	
+	mov	r6,#8
+	mov	a,@r1
+000$:
+	rrc	a
+	jnc	001$
+
+	push	ACC
+	push	AR0
+	push	AR1
+	push	AR7
+	mov	r1,AR0
+	mov	r0,AR2
+	lcall	long_add
+	pop	AR7
+	pop	AR1
+	pop	AR0
+	pop	ACC	
+
+001$:
+	push	ACC
+	push	AR7
+	push	AR0
+	clr	c
+	lcall	long_rlc
+	pop	AR0
+	pop	AR7
+	pop	ACC
+
+	djnz	r6,000$
+	ret	
+	__endasm;
+}
+
+
diff --git a/mc8051fun.h b/mc8051fun.h
index a3e8767..bbcd6bb 100644
--- a/mc8051fun.h
+++ b/mc8051fun.h
@@ -91,6 +91,7 @@ uint8_t multest(uint8_t a, uint8_t b);
 void bcd_tolong(__idata uint8_t *bcdval, __idata uint8_t *binval, uint8_t bcdlen, uint8_t binlen) __reentrant;
 void long_invert(__idata uint8_t *val, uint8_t len) __reentrant;
 uint8_t long_add(__idata uint8_t *v1, __idata uint8_t *v2,uint8_t len) __reentrant;
+uint8_t long_mul(__idata uint8_t *v1, __idata uint8_t *v2,uint8_t len, __idata  uint8_t *result) __reentrant;
 
 
 #endif