如何从用户输入[ASM，DOS]写入文件

Question

我想做一个在控制台中输入文件名时创建文件的过程，我该怎么做？ 我已经尝试了这两个过程：

filenameStr db 13,0,13 dup("$")
createline db 10,13,"/c/ ","$"
space db " ","$"
filehandle dw 0

过程：

proc Createfile
mov dx,offset createline
mov ah,9h
int 21h
mov dx,offset space 
mov ah,9h 
int 21h
mov dx,offset filenameStr
mov bx,dx
mov [byte ptr bx],13    ;8+1+3+1
mov ah,0Ah
int 21h
mov dx,offset filenameStr + 2
mov ah,9h
int 21h
mov [byte ptr filenameStr+2+8],0
call OpenFile 
xor  bx,bx
call WipeClean
call CreateFile1
call CloseFile 
call GetCommandLetter
endp CreateFile

和：

proc CreateFile1
    mov ah,3ch
    mov cx,00000000b
    lea dx,[filenameStr]
    int 21h
    mov [filehandle],ax 
    ret
endp CreateFile1

注意：这些过程不会显示在代码中，因为我已将代码更改为没有写入文件过程的旧代码。

完整程序在这里：

IDEAL
MODEL small
STACK 100h
DATASEG
szMsg1 db "Hi! What do you want to do?",10,13,10,13,"/h-help(see all the commands)",10,13,"/e-Exit",10,13,10,13,"$"
szHelloWorld db 10,13,"Hello World!",10,13,"$"
ErrorMsg db 10,13,"Illegal Command,Try again!",10,13,"$"
filenameStr db 13,0,13 dup("$")
help db 10,13,"HELP LIST:",10,13,"-----------",10,13,"Commands are:",10,13," /e-Exit",10,13," /h-help",10,13," /1-Says: 'Hello World!'",10,13,"$"
filename db ?,0
filehandle dw 0
ErrorOpenMsg db 'Error',10,13,'$'
FileNameLength db "file name consists of 8 letters max! (dont forget to add '.txt' at the end of the name: 'example.txt')",10,13,"/r/ ","$"
fileString db 255 dup (0)
space db " ","$"
CommandMsg db 10,13,"Enter your command:",10,13,"Command: ","$",10,13
filereaderline db "file's text:","$"

CODESEG     
proc WipeClean
     mov  [byte ptr fileString + bx], 0
     inc  bx
     cmp  bx, 255
     jb   WipeClean
endp WipeClean   
proc OpenFile
;Open file
    mov ah,3Dh
    xor al,al
    lea dx,[filenameStr+2]
    int 21h
    jc openerror
    mov [filehandle],ax
    ret
openerror:  
    mov dx,offset ErrorOpenMsg
    mov ah,9h
    int 21h
    ret
endp OpenFile   
proc ReadFile
    mov ah,3fh
    mov bx,[filehandle]
    mov cx,255
    lea dx,[fileString]
    int 21h
    ret
endp ReadFile   
proc DeleteFile
    mov ah,41h
    lea dx,[filenameStr+2]
    int 21h
endp DeleteFile
proc DisplayFileString
    mov ah,09h
    lea dx,[fileString]
    int 21h 
endp DisplayFileString  
proc KeyStroke
    xor ax,ax
    int 16h
endp KeyStroke
proc WriteToFile
    mov ah,40h
    mov bx,[filehandle]
    mov cx,255
    lea dx,[fileString]
    int 21h
    ret
endp WriteToFile
proc CloseFile
    mov ah,3Eh
    mov bx,[filehandle]
    int 21h
    ret
endp CloseFile  
start:
    mov ax, @data
    mov ds, ax
    mov ah,0
    mov al,2
    int 10h
    mov dx,offset szMsg1
    mov ah,9h
    int 21h
    jmp GetCommandLetter
_Error:
    mov dx,offset ErrorMsg
    mov ah,9h
    int 21h 
GetCommandLetter:
    mov dx,offset CommandMsg
    mov ah,9h
    int 21h
    mov ah, 1h
    int 21h
    mov bl,al   
    mov ah, 1h
    int 21h
    mov bh,al   
compare:    
    cmp bl,'/'
    jne _Error
    cmp bh,'h'
    je _help
    cmp bl,'/'
    jne _Error
    cmp bh,'H'
    je _help
    cmp bl,'/'
    jne _Error
    cmp  bh,'1'
    je PrintLine
    cmp bl,'/'
    jne _Error
    cmp bh,'e'
    je _exit
    cmp bl,'/'
    jne _Error
    cmp bh,'E'
    je exit

    mov dx,offset space
    mov ah,9h
    int 21h
    mov dx,offset FileNameLength
    mov ah,9h
    int 21h
    cmp bl,'/'
    jne _Error
    cmp  bh,'r'
    je GetFileName
    cmp bl,'/'
    jne _Error
    cmp  bh,'R'
    je GetFileName
    jmp _Error
_exit:
    jmp exit
_help:  
    mov dx,offset help
    mov ah,9h
    int 21h
    jmp GetCommandLetter
GetFileName:
    mov dx,offset space 
    mov ah,9h 
    int 21h
    mov dx,offset filenameStr
    mov bx,dx
    mov [byte ptr bx],13    ;8+1+3+1
    mov ah,0Ah
    int 21h
    mov dx,offset filenameStr + 2
    mov ah,9h
    int 21h
    mov [byte ptr filenameStr+2+8],0
    call OpenFile 
    xor  bx,bx
    call WipeClean
    call ReadFile
    mov dx,offset filereaderline 
    mov ah,9h 
    int 21h
    call DisplayFileString
    call CloseFile 
    jmp GetCommandLetter


PrintLine:
    mov dx, offset szHelloWorld
    mov ah, 9h
    int 21h
    jmp GetCommandLetter
exit:
    mov ax, 4c00h
    int 21h
END start

Answer 1

阅读DOS api，您会发现CreateFile和OpenFile是非常相似的函数。在您的程序中，您已成功打开，但是您在创建时失败了，因为您犯了与以前相同的错误，当时用户@SepRoland帮助您。您忘记了实际文件名从您提供给 DOS 的结构中的偏移量 2 开始。

proc CreateFile1
    mov ah,3ch
    mov cx,00000000b
    lea dx,[filenameStr +2]             <= Add the 2 here!
    int 21h
    jc  ThisIsAnErrorOnCreatingAFile    <= Do something with the carry flag!
    mov [filehandle],ax 
    ret
endp CreateFile1