diff --git a/lab-1/fib.s b/lab-1/fib.s
index 14c6734..5acf6e0 100644
--- a/lab-1/fib.s
+++ b/lab-1/fib.s
@@ -9,35 +9,25 @@
 	.type fibonacci, function
 
 fibonacci:
-	@ ADD/MODIFY CODE BELOW
+@ ADD/MODIFY CODE BELOW
 	@ PROLOG
-	push {r3, r4, r5, lr}
-
-	@ R4 = R0 - 0 (update flags)
-	@ if(R0 <= 0) goto .L3 (which returns 0)
-
-	@ Compare R4 wtih 1
-	@ If R4 == 1 goto .L4 (which returns 1)
-
-	@ R0 = R4 - 1
-	@ Recursive call to fibonacci with R4 - 1 as parameter
-
-	@ R5 = R0
-	@ R0 = R4 - 2
-	@ Recursive call to fibonacci with R4 - 2 as parameter
-
-	@ R0 = R5 + R0 (update flags)
-
-	pop {r3, r4, r5, pc}		@EPILOG
+	push {r3, r4, r5, r6, r7, lr}
+	
+	mov  r4, r0  @counter
+	mov  r5, #0
+	sub  r5, r5, #1   @previous
+	mov  r6, #0
+	add  r6, r6, #1   @result
+.L1:	
+	sub r4, r4, #1
+	add r7, r5, r6   @r7 = sum = previous + result
+	mov r5, r6
+	mov r6, r7
+	cmp r4 ,#-2
+		bgt .L1
+        mov r0, r5
+	pop {r3, r4, r5, r6, r7, pc}		@EPILOG
 
 	@ END CODE MODIFICATION
-.L3:
-	mov r0, #0			@ R0 = 0
-	pop {r3, r4, r5, pc}		@ EPILOG
-
-.L4:
-	mov r0, #1			@ R0 = 1
-	pop {r3, r4, r5, pc}		@ EPILOG
-
 	.size fibonacci, .-fibonacci
 	.end
diff --git a/lab-2/mutex.s b/lab-2/mutex.s
index d23565d..983fdf4 100644
--- a/lab-2/mutex.s
+++ b/lab-2/mutex.s
@@ -9,7 +9,13 @@
 	.type lock_mutex, function
 lock_mutex:
         @ INSERT CODE BELOW
-
+	ldr r1, =locked
+.L1:
+	ldrex r2, [r0]
+	cmp r2, #0
+		strexeq r2, r1, [r0]
+		cmpeq r2, #0
+		bne .L1
         @ END CODE INSERT
 	bx lr
 
@@ -19,7 +25,8 @@ lock_mutex:
 	.type unlock_mutex, function
 unlock_mutex:
 	@ INSERT CODE BELOW
-        
+        ldr r1, =unlocked
+	str r1, [r0]
         @ END CODE INSERT
 	bx lr
 	.size unlock_mutex, .-unlock_mutex
diff --git a/lab-3/Makefile b/lab-3/Makefile
index 2d0e91d..c708bfc 100644
--- a/lab-3/Makefile
+++ b/lab-3/Makefile
@@ -27,4 +27,4 @@ QEMU_CMD = qemu-arm -g 1234 -L /usr/arm-linux-gnueabihf ./fibseq &
 CMD = yes 9 | $(call QEMU_CMD) && sleep 1
 qemu: fibseq
 	yes 7 | $(call QEMU_CMD)
-	arm-none-eabi-gdb -x gdbscript fibseq
+	arm-none-eabi-gdb fibseq
diff --git a/lab-3/Makefile~ b/lab-3/Makefile~
new file mode 100644
index 0000000..2d0e91d
--- /dev/null
+++ b/lab-3/Makefile~
@@ -0,0 +1,30 @@
+CC	= arm-linux-gnueabihf-gcc
+CFLAGS	= -O0 -Wall -g
+LDFLAGS = -fno-stack-protector
+
+objects	= fibseq.o fib.o
+
+default: fibseq
+
+.PHONY: default clean qemu
+
+fibseq: $(objects)
+	$(CC) $(LDFLAGS) -o $@ $^
+
+fib.o: fib.s
+fibseq.o: fibseq.c
+
+%.o: %.c
+	$(CC) -c $(CFLAGS) -o $@ $<
+
+%.o: %.s
+	$(CC) -c $(CFLAGS) -o $@ $<
+
+clean:
+	rm -f $(objects) fibseq
+
+QEMU_CMD = qemu-arm -g 1234 -L /usr/arm-linux-gnueabihf ./fibseq &
+CMD = yes 9 | $(call QEMU_CMD) && sleep 1
+qemu: fibseq
+	yes 7 | $(call QEMU_CMD)
+	arm-none-eabi-gdb -x gdbscript fibseq
diff --git a/lab-3/fib.s b/lab-3/fib.s
index 14c6734..5acf6e0 100644
--- a/lab-3/fib.s
+++ b/lab-3/fib.s
@@ -9,35 +9,25 @@
 	.type fibonacci, function
 
 fibonacci:
-	@ ADD/MODIFY CODE BELOW
+@ ADD/MODIFY CODE BELOW
 	@ PROLOG
-	push {r3, r4, r5, lr}
-
-	@ R4 = R0 - 0 (update flags)
-	@ if(R0 <= 0) goto .L3 (which returns 0)
-
-	@ Compare R4 wtih 1
-	@ If R4 == 1 goto .L4 (which returns 1)
-
-	@ R0 = R4 - 1
-	@ Recursive call to fibonacci with R4 - 1 as parameter
-
-	@ R5 = R0
-	@ R0 = R4 - 2
-	@ Recursive call to fibonacci with R4 - 2 as parameter
-
-	@ R0 = R5 + R0 (update flags)
-
-	pop {r3, r4, r5, pc}		@EPILOG
+	push {r3, r4, r5, r6, r7, lr}
+	
+	mov  r4, r0  @counter
+	mov  r5, #0
+	sub  r5, r5, #1   @previous
+	mov  r6, #0
+	add  r6, r6, #1   @result
+.L1:	
+	sub r4, r4, #1
+	add r7, r5, r6   @r7 = sum = previous + result
+	mov r5, r6
+	mov r6, r7
+	cmp r4 ,#-2
+		bgt .L1
+        mov r0, r5
+	pop {r3, r4, r5, r6, r7, pc}		@EPILOG
 
 	@ END CODE MODIFICATION
-.L3:
-	mov r0, #0			@ R0 = 0
-	pop {r3, r4, r5, pc}		@ EPILOG
-
-.L4:
-	mov r0, #1			@ R0 = 1
-	pop {r3, r4, r5, pc}		@ EPILOG
-
 	.size fibonacci, .-fibonacci
 	.end