hi

.gitignore

@@ -1 +1,2 @@
 *.o
+*.0

lab-1/fib.s

@@ -13,20 +13,22 @@ fibonacci:
 	@ 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)
+	subs r4,r0,#0                   //R4 = R0 - 0 (update flags)
+
+	cmp r0 #0                       //if(R0 <= 0) goto .L3 (which returns 0)
+	ble .L3
+
+	cmp r4,#1			// Compare R4 wtih 1
+	beq .L4				// If R4 == 1 goto .L4 (which returns 1)
+
+	subs r0,r4,#1 			// R0 = R4 - 1
+	bl fibonacci			// Recursive call to fibonacci with R4 - 1 as parameter
+	addi r5,r5,#0			// R5 = R0
+
+	subs r0,r4,#2			// R0 = R4 - 2
+	bl fibonacci			// Recursive call to fibonacci with R4 - 2 as parameter
+
+	add r0,r5,r0			// R0 = R5 + R0 (update flags)
 
 	pop {r3, r4, r5, pc}		@EPILOG
 

lab-2/mutex.s

@@ -9,19 +9,28 @@
 	.type lock_mutex, function
 lock_mutex:
         @ INSERT CODE BELOW
+	ldr r2,=locked  //load value of locked and save to r2
 
+luck_loop:
+	//When No.(x-1) thread enter,it will modify flag of r1 for tell No.x "I'm working."
+	//r1 is locked-flag in the program
+	ldrex r1,[r0]  //As point, That's enter address of r0 to load it and save to r1.
+	cmp r1,#locked
+	beq luck_loop //if No.(x-1) still work, return to wait.
+	strex r1,r2,[r0] //Save the state from [r0] to r2 is success?
+	cmp r1,#success
+	bne luck_loop
         @ END CODE INSERT
 	bx lr
 
 	.size lock_mutex, .-lock_mutex
-
 	.global unlock_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
-
 	.end