分享一道西电微机实验汇编题，肝了几个小时，写得也不怎么样
编写Q=a+(b-c)*d的程序。（a、b、c、d为0-9间的正整数）要求：a、b、c、d均从键盘输入，计算结果在虚拟终端上显示。
data segment
str1 DB 'PLEASE INPUT A NUMBER TO a:$'
str2 DB 'PLEASE INPUT A NUMBER TO b:$'
str3 DB 'PLEASE INPUT A NUMBER TO c:$'
str4 DB 'PLEASE INPUT A NUMBER TO d:$'
str5 DB 'The answer is:Q=a+(b-c)*d=$'
fuhao db '-$'
a DB 0
b DB 0
c DB 0
d DB 0
Q db 0
pkey db "press any key...$"
ends
stack segment
dw 128 dup(0)
ends
code segment
main proc far
ASSUME CS:CODE,DS:DATA,SS:STACK
start:
MOV AX, DATA
MOV DS, AX
MOV ES, AX
LEA DX,str1
MOV AH,9
INT 21H
CALL input
mov a,bl
LEA DX,str2
MOV AH,9
int 21h
CALL input
mov b,bl
LEA DX,str3
MOV AH,9
INT 21H
call input
mov c,bl
LEA DX,str4
MOV AH,9
INT 21H
call input
mov d,bl
lea dx,str5
mov ah,9
int 21h
mov ax,0
mov bx,0
mov al,b
mov bl,c
cmp al,c
jna calculator
jmp normal
calculator:
sub bl,al
mov al,d
mul bl
mov bl,a
cmp bl,al
jna buzhidao
jmp natural
buzhidao:
sub al,bl
cmp al,0
je printling
mov Q,al
mov bx,0ah
mov cx,0
lea dx,fuhao
mov ah,9
int 21h
mov ax,0
mov al,Q
jmp trans
natural:
sub bl,al
mov al,bl
mov bx,0ah
mov cx,0
jmp trans
normal:
sub al,bl
mov bl,d
mul bl
mov bl,a
add al,bl
mov bx,0ah
mov cx,0
jmp trans
trans:
mov dx,0
div bx
push dx
inc cx
cmp ax,0
je print
cwd
jmp trans
print:
pop dx
add dl,30h
mov ah,2h
int 21h
loop print
HLT
printling:
mov dl,0
add dl,30h
mov ah,2h
int 21h
;退出操作
mov ah,2
mov dl,10
int 21h
lea dx,pkey
mov ah,9
int 21h
mov ah,1
int 21h
mov ax,4c00h
int 21h
ret
main endp
input proc
mov bx,0
mov ah,1
int 21h
cmp al,0dh
je exit
sub al,30h
mov bl,al
jmp exit
exit:
call crlf
ret
input endp
crlf proc near
mov dl,0ah
mov ah,2h
int 21h
mov dl,0dh
mov ah,2h
int 21h
ret
crlf endp
ends
end start