Question

1. If DS-1000H, BX-0200H, SI-O2H, the contents of Memory units10200H 10205H are respectively 10H, 2AH, 3CH, 46H 59H、6BH. What is the contents of the AX Register after each of the following instructions is executed? (1)MOV AX, 0200H (3)MOV AX, BX (5)MOV AX, [BX+SI (2) MOV AX, [200H (4) MOV AX, 3BXI (6) MOV AX, 2[BX+SI] 2, If DS 1000H, ES-2000H, SS-3500H, SI-00AOH, DI-0024H, BX-01 00H, BP-0200H. The Offset Address of the variable named VAL in the data segment is 0030H What is the addressing method of the following instructions? What is the physical address of the following instruction?

Answer 1

Given DS = 1000H, BX = 0200H, SI = 02H (i) MOV A times .0200H 10200H rightarrow 10H 10201 rightarrow 2AH 10202 rightarrow 3CH 10203 rightarrow 46H 10204 rightarrow 59H 10205 rightarrow 68H Physical address = (segment odd times 10H) + off set address Implies PA = (1000 times 10) + 0200 = 10200 Therefore AX = 10H (ii) MOV Ax, [200 H] It is in Register indirect mode 200H rightarrow 10 (iii) MOV AX, BX AX = 0200H (iv) MOV AX, 3[BX] AX = 3 (10) = 30 AX = 30H (v) MOV AX, [BX + SI] PA = (1000 times 10) + (0200 + 02) = 10202 AX + 3CH \r\n (vi) MOV AX, 2 [BX + SI] AX + 2 (3C) AX = 78H (2) DS = 1000H, off set address = 0030H Register indirect addressing mode. PA = seg add times 10H + off set add = (1000 times 10) + 0030 PA = 10030H