CS401 Computer Architecture and Assembly Language Prograaming Assignment No.2 Solution FALL 2014

Question No.1 Solution

1.      mov [bx+si+di],ax

         physical address = segment * 0x10 + ea

&

                   ea  = bAse + index + offset  

                   ea  =  a12eh + 0010 +0300

                         =  af24h

            physical address = segment * 0x10 + ea

                                              =  ds + ea

                                              =       22eah + af24h

                                              =   0x321934

2.      ADD AX,[BP+12]

                  physical address = segment * 0x10 + ea

&

  ea  = bAse + index + offset 

  ea =  420ah + 02ach + 12

       =  44434

so,

 physical address = segment * 0x10 + ea

                                         = 0fe0h +44434

                                         = 0x45948

Question No. 1:                                                                                   

We have the following register values:

AX = 420AH,

BX = A12EH,

DS = 22EAH,

CS = 0100H,

ES = 0FEAH,

SS = 0FE0H,

SI = 0010,

BP = 02ACH and

DI = 0300H.

You are required to calculate the physical address generated by each of the following instructions?

·         mov [bx+si+di],ax

·         ADD AX,[BP+12]  

Solution:

1.mov [bx+si+di],ax

          EA=    A12EH+0010+ 0300

                 =AF24H

Physical address  = segment*0x10+EA

                                = DS +EA

                                =22EAH + AF24H

                                  =0x321934

             

                  

·          ADD AX,[BP+12]  

                  EA = 420AH , [02ACH+12]

                       =  ADD    420AH,   02424

                        = 44434

            Physical address  = segment*0x10+EA

                                             =SS+EA

                                             = 0FE0H+44434

                                             =0x45948

	Instruction	Register current value after the instruction execution		IP (Instruction Pointer)	Flags
					OF		CF			ZF		PF		SF		AF
1	[ORG 0X0100]	AX	0000	0100	0	0			0		0		0		0
		BX	0000
		CX	0028
		DX	0000
2	MOV CX, 10	AX	0000	0103	0	0			0		0		0		0
		BX	0000
		CX	0005
		DX	0000
3	XOR AX, AX	AX	0000	0105	0	0			1		1		0		0
		BX	0000
		CX	0005
		DX	0000
4	MOV BX, NUM	AX	0000	0108	0	0			1		1		0		0
		BX	011C
		CX	0005
		DX	0000
5	ADD AX, [BX]	AX	0000	010A	0	0			1		1		0		0
		BX	011C
		CX	0005
		DX	0000
6	ADD BX, 2	AX	0000	010E	0	0			0		1		0		0
		BX	011E
		CX	0005
		DX	0000
7	SUB CX, 1	AX	0000	0112	0	0			0		0		0		0
		BX	011E
		CX	0004
		DX	0000
8	JNZ L1	AX	0000	0108	0	0			0		0		0		0
		BX	011E
		CX	0004
		DX	0000
9	ADD AX, [BX]	AX	0001	010A	0			0	0		0		0		0
		BX	011E
		CX	0004
		DX	0000
10	ADD BX, 2	AX	0001	010E	0			0	0		0		0		1
		BX	0120
		CX	0004
		DX	0000
11	SUB CX, 1	AX	0001	0112	0			0	0		1		0		0
		BX	0120
		CX	0003
		DX	0000
12	JNZ L1	AX	0001	0108	0			0	0		1		0		0
		BX	0120
		CX	0003
		DX	0000
13	ADD AX, [BX]	AX	0003	010A	0			0	0		1		0		0
		BX	0120
		CX	0003
		DX	0000
14	ADD BX, 2	AX	0003	010E	0			0	0		1		0		0
		BX	0122
		CX	0003
		DX	0000
15	SUB CX, 1	AX	0003	0112	0			0	0		0		0		0
		BX	0122
		CX	0002
		DX	0000
16	JNZ L1	AX	0003	0108	0			0	0		0		0		0
		BX	0122
		CX	0002
		DX	0000
17	ADD AX, [BX]	AX	0006	010A	0			0	0		1		0		0
		BX	0122
		CX	0002
		DX	0000
18	ADD BX, 2	AX	0006	010E	0			0	0		1		0		0
		BX	0124
		CX	0002
		DX	0000
19	SUB CX, 1	AX	0006	0112	0			0	0		0		0		0
		BX	0124
		CX	0001
		DX	0000
20	JNZ L1	AX	0006	0108	0			0	0		0		0		0
		BX	0124
		CX	0001
		DX	0000
21	ADD AX, [BX]	AX	000A	010A	0			0	0		1		0		0
		BX	0124
		CX	0001
		DX	0000
22	ADD BX, 2	AX	000A	010E	0			0	0		0		0		0
		BX	0126
		CX	0001
		DX	0000
23	SUB CX, 1	AX	000A	0112	0			0	0		1		0		0
		BX	0126
		CX	0000
		DX	0000
24	JNZ L1	AX	000A	0114	0			0	1		1		0		0
		BX	0126
		CX	0000
		DX	0000
25	MOV [SUM], AX	AX	000A	0117	0			0		1		1		0		0
		BX	0126
		CX	0000
		DX	0000
26	MOV AX, 0X4C00	AX	4C00	011A	0			0		1		1		0		0
		BX	0126
		CX	0000
		DX	0000
27	INT 0X21	AX	0000	0100	0			0		0		0		0		0
		BX	0000
		CX	0000
		DX	0000