$1.$ Write an explanation for each line of code.

$2.$ Write the logic of each procedure $($function$).$ How does it work?

$3.$ Run all the options of the program and explain in details the logic of the

entire program and how does it achieves its goals

Program$-----$

$.$model small

$\mathrm{.}386$

$.$stack $100$h

$.$data

msg$1$ db $13,10,$ "Enter any number $-->","$$$"$

msg$2$ db "Enter an operation $+,-*$ or $/-->",13,10,"$$$"$

msg$3$ db "The Operation is $-->","$$$"$

msg$4$ db "The result is $-->","$$$"$

By$\_$base dd $21$

by$\_10$ dd $10$

sp$\_$counter db $0$

disp$\_$number dd $0$

disp$\_$number$2$ dd $0$

disp$\_$number$3$ dd $0$

op$\_$type db $0$

last$\_$key dd $0$

remainder db $0$

$.$code

main proc

mov ax$,$@data

mov ds$,$ax

mov dx$,$offset msg$1$

call display$\_$message

call m$\_$keyin

call operation

mov dx$,$offset msg$1$

call display$\_$message

call m$\_$keyin

cmp op$\_$type, $"+"$

jnz short skip$\_$plus

call op$\_$plus

skiP$\_$plus:

cmp op$\_$type, $"-"$

jnz short skip$\_$minus

call op$\_$minus

skip$\_$minus:

cmp op$\_$type, $"*"$

jnz short skip$\_$mul

call op$\_$mult

skip$\_$mul:

cmp op$\_$type, $"/"$

jnz short skip$\_$div

call op$\_$div

skip$\_$div:

call m$\_$display

mov ax$,4$c$00$h

int $21$h

operation proc

mov dx$,$offset msg$2$

rpt$4$:

call display$\_$message

mov dx$,$offset msg$3$

call display$\_$message

mov ah$,1$

int $21$h

cmp al$,30$h

jns rpt$4$

mov op$\_$type, al

ret

operation endp

m$\_$display proc

mov dx$,$offset msg$4$

call display$\_$message

mov eax, disp$\_$number

mov sp$\_$counter, $0$

Base$\_$lp:

LP$1$:

mov edx, $0$

div By$\_$Base

push dx

inc sp$\_$counter

cmp eax, $0$

jnz lp$1$

LP$2$:

pop dx

call display

dec sp$\_$counter

jnz lp$2$

mov edx, $-8$

call display

mov edx, by$\_$base

call display

mov edx, $-7$

call display

dec By$\_$base

mov eax, disp$\_$number

cmp By$\_$base, $1$

jnz Base$\_$lp

ret

m$\_$display endp

op$\_$minus proc

mov eax, disp$\_$number$2$

sub eax, disp$\_$number$3$

mov disp$\_$number, eax

ret

op$\_$minus endp

op$\_$div proc

mov eax, disp$\_$number$2$

div disp$\_$number$3$

mov disp$\_$number, eax

mov remainder, dl

call display

call m$\_$display

mov dl$,-16$

call display

mov dl$,$ remainder

call display

mov dl$,-1$

call display

mov edx, disp$\_$number$3$

call display

mov ax$,4$c$00$h

int $21$h

op$\_$div endp

op$\_$mult proc

mov eax, disp$\_$number$2$

mul disp$\_$number$3$

mov disp$\_$number, eax

ret

op$\_$mult endp

op$\_$plus proc

mov eax, disp$\_$number$2$

add eax, disp$\_$number$3$

mov disp$\_$number, eax

ret

op$\_$plus endp

display proc

add dl$,30$h

cmp dl$,3$ah

js short skip$\_$hex

add dl$,7$

Skip$\_$hex:

mov ah$,6$

int $21$h

ret

display endp

display$\_$message proc

mov ah$,9$

int $21$h

mov edx, $0$

ret

display$\_$message endp

m$\_$keyin proc

MOV disp$\_$number, $0$

mov last$\_$key, $0$

LP$\_$key:

mov eax, disp$\_$number

mul by$\_10$ ; eax $=($eax$)*10$

add eax, last$\_$key

mov DISP$\_$NUMBER, eax

mov ah$,1$

int $21$h

AND eax, $000000$ffh

cmp al$,13$

jz short finkey

sub al$,30$h

MOV LAST$\_$KEY, EAX

jmp lp$\_$key

finkey:

MOV eax, DISP$\_$NUMBER

cmp DISP$\_$NUMBER$2,0$

jnz short skip

MOV DISP$\_$NUMBER$2,$ EAX

skip:

MOV DISP$\_$NUMBER$3,$ EAX

ret

m$\_$keyin endp

main endp

end main