Part 1: Write a program for a basic calculator that performs 3 operations: addit

Question

Part 1:

Write a program for a basic calculator that performs 3 operations: addition, subtraction, and multiplication of two 1-byte numbers N1 and N2. One of these operat ions is performed based on an input op_code as follows:

• Op_code=1 the program performs addition and stores the result in SUM

• Op_code=2 the program performs subtraction and stores the result in Diff

• Op_code=3 the program performs multiplication and stores the result PROD

Create a project using MPLAB (follow all the steps described in the previous lab activity). Modify the program to meet the requirement of this lab 2 and test it using different data inputs.

For the 2nd part:

Add more operations to the calculator of Problem 1. This revised calculator should be able to compute division, the first 3 powers of any number, and also the basic logic operations (AND, OR, XOR, and Not). Revise the program and test it using appropriate inputs.

Explanation / Answer

jmp start ;**************************** ;* Program to read in two * ;* numbers and add them * ;* and print out the result * ;**************************** number db 7 dup 0 ; string which will store input and output n1 dw 0 ; two input variables n2 dw 0 res dw 0 ; one output variable cr dw 13,10,"$" ; carriage return, line feed start: mov dx,offset number mov bx,dx mov b[bx],5 ; maximum 5 characters to read mov ah,0ah int 21h ; read in a string from keyboard mov bx,offset number +1 mov cx,00 mov cl,[bx] ; cl now contains number of digits mov ax,00 ; ax will contain the number input usedigit: inc bx ; get next digit shl ax,1 ; multiply by 10 using 2 shift ops and an add... mov dx,ax ; ... x*8 + x*2 = x*10 is the principle. shl ax,2 add ax,dx ; ax is now multiplied by 10 mov dx,00 mov dl,[bx] ; dl has new character sub dx,48 ; subtract 48 = ascii('0') to get number value add ax,dx ; add to ax loop usedigit ; loop statement= jmp if cx > 0 cmp n1,00 ; see if this is first or second number read jnz second mov n1,ax ; assign it to the first variable jmp start ; read in another number second: mov n2,ax ; or assign to second variable and continue print_cr: mov ah,09 mov dx,offset cr ; print out a carriage return character int 21h addnos: mov ax,n1 ; move numbers to registers ... mov bx,n2 add ax,bx ; ...and add mov res,ax ; store the result mov cx,00 setup_string: mov bx,offset number+7 ; put a $ at end of buffer. mov b[bx],'$' ; we will fill buffer from back forwards dec bx mov ax,res convert_decimal: mov dx,10 div dl ; divide by 10 add ah,48 ; convert remainder to character mov [bx],ah ; and move to buffer for output dec bx mov ah,00 ; quotient becomes new value cmp ax,00 ; if we haven't got all digits divide again jnz convert_decimal printout: mov dx,bx inc dx ; we decremented once too many, go forward one. mov ah,09 int 21h ; output the string close: mov ah,4ch mov al,00 int 21h ; end program

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