Question

Write an LC-3 program (machine code) that compares the two numbers located in x3600 and x3601 and puts the value 0 in R1 if the two numbers are equal, 1 if the first number is larger than the second number, and -1 if the first number is smaller than the second number.

Answer 1

1). ANSWER :

GIVENTHAT :

To write an LC-3 program

.ORIG x3500

LDI R1,x3600 ; Load R1 from memory content at x36000

LDI R2,x3601 ;Load R1 from memory content at x36001

AND R0,R0,#0 ;Initilize R0=0

NOT R3,R2 ;Negate Number 2

ADD R4,R3,R1 ;R4=R1-R3;

BRz eq ; if above step results zero,which indiacates both numbers are equal zero flag enabled

BRn le ;if above step results negative value negative flag enabled ,which indiacates first  numbers ;smaller than second number

BRp gr    ;if above step results negative value negative flag enabled ,which indiacates first  numbers ;igger than second number

eq  AND R0,R0,#0 ;make  R0=0

BRnzp end

le ADD R0,R0,#-1 ;R0=-1

BRnzp end

gr ADD R0,R0,#1 ;R0=1

   BRnzp end

HALT ;End