Add ES/Lab/LAB4/GCD.asm

ES/Lab/LAB4/GCD.asm

@@ -0,0 +1,41 @@
+	AREA RESET, DATA, READONLY
+	EXPORT __Vectors
+__Vectors
+	DCD 0x10001000
+	DCD Reset_Handler
+	ALIGN
+
+	AREA MYCODE, CODE, READONLY
+	ENTRY
+	EXPORT Reset_Handler
+
+Reset_Handler
+	MOV	r0, #48
+	MOV	r1, #18
+
+GCD_Loop
+	CMP	r0, r1
+	BEQ	GCD_Done
+	BGT	GT_A_B
+	SUB	r1, r1, r0
+	B	GCD_Loop
+
+GT_A_B
+	SUB	r0, r0, r1
+	B	GCD_Loop
+
+GCD_Done
+	LDR	r2, =result
+	STR	r0, [r2]
+
+LoopForever
+	B	LoopForever
+
+	ALIGN
+
+	AREA MYDATA, DATA, READWRITE
+numA	DCD	48
+numB	DCD	18
+result	DCD	0
+
+	END