; program to print 16 bit numerical values in hexadecimal

.model small
.386
.stack 100h

.data

; ascii values of hex digits 0-F
asciis db 48,49,50,51,52,53,54,55,56,57,65,66,67,68,69,70
buffer db 64 dup(0)		; not used
endl   db 13,10,'$'

.code

mymain proc
start: 	mov ax,@data
	mov ds,ax
; assume value to be printed is in cx
	mov cx,111   ; sample value
	call printhex
	mov cx,0abcdh
	call printhex
	mov ax,4c00h
	int 21h
mymain endp

;printhex proc   
printhex:
	push ax		; save registers
	push bx
	push dx

	mov dx,cx
	shr dx,12 	; first 4 bits now can be used as offset
	mov bx,offset asciis
	add bx,dx
	mov dl,[bx]
	mov ah,2
	int 21h  	; print the first char
	mov dx,cx
	and dx,0F00h	; mask out other 12 bits before shift
	shr dx,8
	mov bx,offset asciis
	add bx,dx
	mov dl,[bx]
	int 21h		; print second char
	mov dx,cx
	and dx,00F0h
	shr dx,4
	mov bx,offset asciis
	add bx,dx
	mov dl,[bx]
	int 21h		; print the third char
	mov dx,cx
	and dx,000Fh
	mov bx,offset asciis
	add bx,dx
	mov dl,[bx]
	int 21h		; print the last char
	mov dx,offset endl	; print "\n"
	mov ah,9
	int 21h

	pop dx		; restore registers and return
	pop bx
	pop ax
	ret
;printhex endp
end