一位数字输入结果为两位数字输出组合

Question

任务是从用户那里获得一位数的输入并输出1-2位数。我不知道为什么它不能在1位数+1位数=1位数上工作，为什么有时它在1位数+1位数=2位数上工作但有时不行。它还包括减法、乘法、除法和模运算。

标题

;-----------------------------------------------------
.MODEL SMALL
.STACK 64
.DATA
INPUT DB 13, 10, "Enter input : ","$"
SUM DB 13,10, "The sum is : ","$"
DIFF DB 13,10, "The difference is : ","$"
MULTI DB 13,10, "The product is : ","$"
DIVI DB 13,10, "The quotient is : ","$"
MODULO DB 13,10, "The modulo is : ","$"
NUM1 db ?
NUM2 db ?
OP db ?
RES db ?
;-----------------------------------------------------
.CODE
MAIN PROC NEAR
MOV AX,@DATA
MOV DS,AX
; outputs "input" message
LEA DX, INPUT
MOV AH, 09h
INT 21h
; get first input
MOV AH, 01h
INT 21h
SUB AL, '0'
MOV NUM1, AL
; get operand
MOV AH, 01h
INT 21h
MOV OP, AL
; get second input
MOV AH, 01h
INT 21h
SUB AL, '0'
MOV NUM2, AL
CMP OP, "+"
JE @ADD
CMP OP, "-"
JE @SUB
CMP OP, "*"
JE @MULTIPLY
CMP OP, "/"
JE @DIVIDE
CMP OP, "%"
JE @MOD
@ADD :
ADD AL, NUM1
MOV RES, AL
LEA DX, SUM
MOV AH, 09h
INT 21h
JMP @PRINT
@SUB :
MOV AL, NUM1
CMP AL, NUM2
JG @WITHOUTNEG
JMP @WITHNEG
@WITHNEG :
MOV AL, NUM2
SUB AL, NUM1
MOV RES, AL
LEA DX, DIFF
MOV AH, 09h
INT 21h
MOV OP, "-"
MOV DL, OP
MOV AH,02h
INT 21h
JMP @PRINT
@WITHOUTNEG :
MOV AL, NUM1
SUB AL, NUM2
MOV RES, AL
LEA DX, DIFF
MOV AH, 09h
INT 21h
JMP @PRINT
@MULTIPLY :
MOV AL, NUM1
IMUL NUM2
MOV RES, AL
LEA DX, MULTI
MOV AH, 09h
INT 21h
JMP @PRINT
@DIVIDE :
XOR AX, AX
MOV AL, NUM1
IDIV NUM2
MOV RES, AL
LEA DX, DIVI
MOV AH, 09h
INT 21h
JMP @PRINT
@MOD :
XOR AX, AX
MOV AL, NUM1
IDIV NUM2
MOV RES, AH
LEA DX, MODULO
MOV AH, 09h
INT 21h
JMP @PRINT
@PRINT :
XOR AX, AX
MOV AL, RES
MOV BL, 10
IDIV BL
ADD AL, '0'
MOV DL, AL
MOV AH,02h
INT 21h
ADD AH, '0'
MOV DL, AH
MOV AH,02h
INT 21h
JMP @EXIT
@EXIT :
MOV AH,4Ch
INT 21h
MAIN ENDP
;----------------------------------------------------------------
END MAIN

Answer 1

在"打印"过程中，您正在修改AH，然后尝试稍后使用该值。

MOV AH,02h
INT 21h
ADD AH, '0'

在修改寄存器之前，您必须保留您的值，PUSH和POP指令将对您有所帮助。

PUSH AX
MOV AH,02h
INT 21h
POP AX
ADD AH, '0'

Answer 2

MOV AH,02h
INT 21h

ADD AH, '0'

您在此处使用WRITE CHARACTER函数编号覆盖剩余部分。您需要保存并恢复AH，例如：

MOV DL, AL
PUSH AX   ; Save AX on the stack
MOV AH,02h
INT 21h
POP AX    ; Restore AX
ADD AH, '0'

Answer 3

此处。

.model small
.stack 100h
.data
first db 13,10, 'Enter 1st number: $'
second db 13, 10, 'Enter 2nd number: $'
result db 13,10, 'Result: $'
invalid db 13,10, 'Invalid number!!! $'
.code
start:
    mov ax,03
    int 10h
    mov ax,@data
    mov ds,ax
mn:
    mov dx, offset first
    mov ah, 9
    int 21h
    mov ah, 1
    int 21h
    mov cl, al
    cmp al, 30h
    jl nvalid
    cmp al, 39h
    jg nvalid
    jmp proceed
nvalid:
    mov dx, offset invalid
    mov ah, 9
    int 21h
    jmp mn
proceed:
    sub cl, 30h
    mov dx, offset second
    mov ah, 9
    int 21h
    mov ah, 1
    int 21h
    cmp al, 30h
    jl nvalid
    cmp al, 39h
    jg nvalid
    sub al, 30h
    xor ah,ah
    add al, cl
    aaa
    mov cx, ax
    add cx, 3030h
    mov dx, offset result
    mov ah, 9
    int 21h
    mov ah, 2
    mov dl, ch
    int 21h
    mov dl, cl
    int 21h
exit:
    mov ah, 4ch
    int 21h
end start