CS401 Computer Architecture and Assembly Language Assignment 2 Solution May 2013

Assignment comprises of lectures No. 9-13.
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            [ORG 0100H]
MOV AX, 5
MOV CX, AX
XOR DX, DX
DEC CX
CONT:            MOV BX, CX
MUL BX
DEC CX
JNZ CONT
MOV DX, AX
MOV AX, 0X4C00
INT 0X21
Assemble above assembly language code using NASM and answer the following questions:
Q.1. Execute the code in order to examine how changes are made in registers and memory. Students are required to fill in below table after step by step execution of each instruction in the debugger.          
                                                                                                                        (15 marks)

S No.	INSTRUCTION		REGISTER VALUES		INSTRUCTION POINTER (IP)	FLAG/STATUS REGISTER
						CF	ZF	PF	SF	AF
1	[ORG 0100H]		AX
			BX
			CX
			DX
2	MOV AX,5		AX
			BX
			CX
			DX
3	MOV CX,AX		AX
			BX
			CX
			DX
4	XOR DX,DX		AX
			BX
			CX
			DX
5	DEC CX		AX
			BX
			CX
			DX
6	CONT:	MOV BX,CX	AX
			BX
			CX
			DX
7		MUL BX	AX
			BX
			CX
			DX
8		DEC CX	AX
			BX
			CX
			DX
9		JNZ CONT	AX
			BX
			CX
			DX
10	CONT:	MOV BX,CX	AX
			BX
			CX
			DX
11		MUL BX	AX
			BX
			CX
			DX
12		DEC CX	AX
			BX
			CX
			DX
13		JNZ CONT	AX
			BX
			CX
			DX
14	CONT:	MOV BX,CX	AX
			BX
			CX
			DX
15		MUL BX	AX
			BX
			CX
			DX
16		DEC CX	AX
			BX
			CX
			DX
17		JNZ CONT	AX
			BX
			CX
			DX
18	CONT:	MOV BX,CX	AX
			BX
			CX
			DX
19		MUL BX	AX
			BX
			CX
			DX
20		DEC CX	AX
			BX
			CX
			DX
21		JNZ CONT	AX
			BX
			CX
			DX
22		MOV DX,AX	AX
			BX
			CX
			DX
26	MOV AX,0X4C00		AX
			BX
			CX
			DX

Q.2. Provide the snapshot of debugger showing calculated result stored in DX at the end of our program.                                                                                                                                                                                                                                       (3 marks)
Q.3. Briefly explain the purpose of the given code.
(2 marks)