Computer organization and assembly language Please help me with this. I have to write line by line what each line of codes does. CODE IS BELOW:

Computer organization and assembly language

Please help me with this.

I have to write line by line what each line of codes does.

CODE IS BELOW:

.model small 

.386 

.stack 100h 

.data 

msg1 db 13, 10, "Enter any number --> ", "$"

msg2 db  "Enter an operation +,- * or /  --> ",13, 10, "$"

msg3 db  "The Operation is --> ", "$"

msg4 db  "The result is --> ", "$"

By_base dd 21

by_10 dd 10  ; 32 bits variable with initial value = 10

sp_counter db 0 ; 8 bits variable with initial value of zero

disp_number dd 0 ; 32 bits variable with initial value = 0

disp_number2 dd 0

disp_number3 dd 0

op_type db 0

last_key dd 0 ; 32 bits variable with initial value of zero

remainder db 0

.code 

main proc

mov ax,@data;set up datasegment

movds,ax

        mov dx,offset msg1

call display_message

callm_keyin

calloperation

mov dx,offset msg1

calldisplay_message

callm_keyin

cmpop_type, "+"

jnz short skip_plus

callop_plus

skiP_plus:

cmp op_type, "-"

jnz short skip_minus

callop_minus

skip_minus:

cmp op_type, "*"

jnz short skip_mul

callop_mult

skip_mul:

cmp op_type, "/"

jnz short skip_div

call op_div

skip_div:

call m_display

mov ax, 4c00h 

int 21h 

operation proc

mov dx,offset msg2

rpt4:

call display_message

mov dx,offset msg3

call display_message

mov ah, 1

int 21h

cmp al, 30h

jns rpt4

mov op_type, al

ret

operation endp

m_display proc

mov dx,offset msg4

call display_message

mov eax, disp_number

mov sp_counter, 0

Base_lp:

LP1:

mov edx, 0

div By_Base

push dx

inc sp_counter

cmp eax, 0

jnz lp1

LP2:

pop dx

call display

dec sp_counter

jnz lp2

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_number2

sub eax, disp_number3

mov disp_number, eax

ret

op_minus endp

op_div proc

mov eax, disp_number2

div disp_number3

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_number3

call display

mov ax, 4c00h 

int 21h 

op_div endp

op_mult proc

mov eax, disp_number2

mul disp_number3

mov disp_number, eax

ret

op_mult endp

op_plus proc

mov eax, disp_number2

add eax, disp_number3

mov disp_number, eax

ret

op_plus endp

display proc

add dl, 30h

cmp dl, 3ah

jsshort skip_hex

add dl, 7

Skip_hex:

mov ah, 6

int 21h

ret

display endp

display_message proc

mov ah, 9 ; to display to screen the string pointed by the DX register.

int 21h

mov edx, 0

ret

display_message endp

m_keyin proc

MOV disp_number, 0

mov last_key, 0

LP_key:; location in the program label

mov eax, disp_number

mul by_10  ; eax = (eax) * 10

add eax, last_key

mov DISP_NUMBER, eax  ; save it to the number to display

mov ah, 1 ; enables a single key entry

int 21h

AND eax, 000000ffh

cmp al, 13 ; compare the key entered to 13 i.e. ascii of CR

jzshort finkey ; if CR was pressed then exit the enter key routine

sub al, 30h  ; remove the ascii from the number entered to get a pure number.

MOV LAST_KEY, EAX  ; save the last digit entered

jmp lp_key  ; unconditional jump to the enter key routine in a loop

finkey:

MOV eax, DISP_NUMBER

cmp DISP_NUMBER2,0

jnz short skip

MOV DISP_NUMBER2, EAX

skip:

MOV DISP_NUMBER3, EAX

ret

m_keyin endp

main endp

end main