Question

Q#1 AX contains a numberbetween 0-15. Write code to complement the corresponding bit in BX.For example if AX contains 6; complement the 6th bit of BX. (Note:First bitin BX is at 0th position and last bit is at 15thposition)
Marks10
Q#2 Suppose that AX=0x3412, BX=0x7856, CX= 0x1CAB, and SP=0x100.Given the contents of AX, BX, CX, and SP after executing thefollowing instructions:
PUSH AX
PUSH BX
XCHG AX, CX
POP CX
PUSH AX
POP BX

Answer 1

Q#1 AX contains a number between 0-15. Writecode to complement the corresponding bit in BX. For example if AXcontains 6; complementthe 6th bit of BX.(Note: First bit in BX is at 0^thposition and last bit is at15^thposition)Marks10

Solution:

[org 0x0100]

mov ax,3 ;suppose axcontain 3

movdx,1 ;initial value for complement with bx

cmpax,0;if ax contain 0

jecomplement; go for complement ist bit

movcx,ax ;other wisemove the value in cx

shldx,cl; shift 1 to left for number value in ax

complement:

xorbx,dx;perform comlement operation

mov ax,4ch

int 21h

Q#2 Suppose that AX=0x3412, BX=0x7856, CX=0x1CAB, and SP=0x100. Given the contents of AX, BX, CX, and SPafter executing the followinginstructions:

PUSH AX

PUSH BX

XCHG AX, CX

POP CX

PUSH AX

POP BX

Marks10

SOLUTION:

	AX	BX	CX	SP
PUSH AX	0x3412	0x7856	0x1CAB	0xFE
PUSH BX	0x3412	0x7856	0x1CAB	0XFC
XCHG AX,CX	0x1CAB	0x7856	0x3412	0XFC
POP CX	0x1CAB	0x7856	0x7856	0xFE
PUSH AX	0x1CAB	0x7856	0x7856	0XFC
POP BX	0x1CAB	0x1CAB	0x7856	0xFE