This program displays the current system time by using DOS interrupt 21H function 2CH to retrieve the time from the system. It breaks the time value into hours, minutes, seconds and stores each part separately before converting them to ASCII characters and displaying them along with a colon separator between each part to show the time as HH:MM:SS. The program ends by returning control back to DOS.

1. Write a program to display the current system time using DOS INT 21H, function 2CH.
macro putc c
mov dl, c
mov ah, 2
int 21h
endm
.model small
.data
msg db 10,13,'The current time is:$'
.stack 100
.code
mov ax, @data
mov ds, ax
mov ah, 2ch
int 21h
push dx
mov al,ch
aam
add ax, 3030h
mov bx, ax
putc bh
putc bl
putc ':'
mov al,cl
aam
add ax, 3030h
mov bx, ax
putc bh
putc bl
putc ':'
pop cx
mov al,ch
aam
add ax, 3030h
mov bx, ax
putc bh
putc bl
putc ':'
mov al,cl
aam
add ax, 3030h
mov bx, ax
putc bh
putc bl
mov ah, 4ch
int 21h
end