3.数值显示-汇编语言（王爽）-实验10 编写子程序

; e10_3.asm
assume cs:code,ss:stack,ds:data

data segment
db 16 dup (0)
data ends

stack segment
db 64 dup (0)
stack ends

code segment
start:
mov ax,stack
mov ss,ax
mov sp,64

mov ax,12666
mov bx,data
mov ds,bx
mov si,0    ; set ds:[si]
call dtoc

mov dh,8
mov dl,3
mov cl,2
call show_str
mov ax,4c00h
int 21h
dtoc:
push ax
push bx
push cx
push dx
push ds
push si
push di   ; to record the digits to output

mov di,0
mov bx,10  ; set divisor
s_dtoc:
mov dx,0    ; set (dx),(ax)
div bx      ; [(dx) * 10000h + (ax)] / 10
; result (dx) = remainder, (ax) = quotient
add dx, 30h
push dx   ; save the remainder to stack
inc di
push cx
mov cx,ax
jcxz ok_dtoc    ; to see if quotient (ax) = 0
pop cx    ; this wouldn't be excuted when (ax) = 0
inc cx      ; (cx) = (cx) - 1 after loop s
loop s_dtoc

ok_dtoc:
pop cx
mov cx,di
s1_dtoc:
pop dx
mov ds:[si], dl   ; (dx) < 10 + 30H
inc si
loop s1_dtoc

pop di
pop si
pop ds
pop dx
pop cx
pop bx
pop ax
ret

show_str:
push c
4000
x
push dx
push ds
push si
push ax
push es
push bp
push di

mov ax,0b800h
mov es,ax
mov al,160
mul dh
mov bp,ax
mov al,2
mul dl
mov di,ax

s: push cx
mov ch,0
mov cl,ds:[si]
jcxz ok
pop cx

mov al,ds:[si]
mov es:[bp+di],al
mov es:[bp+di+1],cl
add di,2
inc si
inc cx
loop s

ok:
pop cx
pop di
pop bp
pop es
pop ax
pop si
pop ds
pop dx
pop cx
ret

code ends
end start