Question

我试图打印A-Z

代码MOV CX,[34H]中的

为什么CX相当于26？当我使用该代码时，它给了我A-Z的输出

TITLE SAMPLE PROGRAM USING CMP AND JMP
.MODEL SMALL
.STACK 0100H
.DATA

.CODE
START:

        MOV AX,@DATA
        MOV DS,AX

        MOV AH,02H

        MOV CX,[34H]
        MOV DL,41H

START_LOOP:        

        INT 21H

        INC DL
        DEC CX

        JZ EXIT

        LOOP START_LOOP 



EXIT:   MOV AX,4C00H
        INT 21H


END START

Answer 1

[34H] 是地址，指针。您通过地址34h获取价值。不知何故，有26个。

Answer 2

以下是您的代码修复：

.MODEL SMALL 
.STACK 0100H 
.DATA

.CODE START:

    MOV AX,@DATA
    MOV DS,AX

    MOV AH,02H

    MOV CX,26
    MOV DL,41H

START_LOOP:

    INT 21H
    PUSH DX          ◄■■■ PRESERVE CURRENT LETTER.
    MOV DL,20h       ◄■■■ DL, NOT DH
    INT 21H
    POP DX           ◄■■■ RESTORE CURRENT LETTER.
    INC DL

    LOOP START_LOOP

EXIT:
    MOV AX,4C00H
    INT 21H

修改：AaBbCc ......

.MODEL SMALL 
.STACK 0100H 
.DATA     

upper db 'A'          ◄■■■ VARIABLES TO CONTROL
lower db 'a'          ◄■■■ UPPER AND LOWERCASE LETTER.

.CODE START:

    MOV AX,@DATA
    MOV DS,AX

    MOV AH,02H

    MOV CX,26

START_LOOP:

    MOV DL,upper
    INT 21H                ◄■■■ DISPLAY UPPERCASE LETTER.
    MOV DL,lower
    INT 21H                ◄■■■ DISPLAY LOWERCASE LETTER.     

    INC upper              ◄■■■ NEXT UPPERCASE LETTER.
    INC lower              ◄■■■ NEXT LOWERCASE LETTER.

    LOOP START_LOOP

EXIT:
    MOV AX,4C00H
    INT 21H

如何在汇编语言中使用26

2 个答案: