05_17.asm

清华大学计算机系汇编语言课程

;05_17.asm
;Created by RunningOn Chen.
;2003011434 J34 CS dept, THU
;2005-11-15
;本程序不输出答案，要在debug下才能看出结果


data	segment
	letter	db '0123456789ABCDEF'
	MEM	db 4 dup(?)
data	ends

stack	segment
	dw	10 dup(?)
stack	ends

code	segment
main	proc far
	assume ds:data, cs:code, ss:stack
start:
	push	ds
	mov	ax, 0
	push	ax
	mov	ax, data
	mov	ds, ax
	mov	ax, stack
	mov	ss, ax

	mov	ax, 2a49h
	mov	cx, 4
	mov	di, 0
	mov	si, 4
cycle:					;di = 0;
	mov	bx, ax			;for (cx = 4 ; cx >= 1 ; cx--)
	and	bx, 000fh		;{
	mov	dl, letter[bx]		;	bx = (ax & 0x000f);
	mov	MEM[di], dl		;	MEM[di] = bx;
	inc	di			;	di++;
	push	cx			;	ax >>= 4
	mov	cl, 4			;
	shr	ax, cl			;
	pop	cx			;
	loop	cycle			;}

exit:
	ret

main	endp
code	ends
	end start