How to print ASCII code from Function 01h

Comments

• IDK

  August 2007

  : I am looking for guidance on how to print the hex value of a number
  : entered from the keyboard. Enter a value when prompted, for comment
  : consistency enter the number 4. I want that number 4 to display the
  : cooresponding value in hex. IE, enter 4 on keyboard, print 34 on
  : the screen. The value I want to print is located in AL, but I can
  : only display the enter value of 4. How do I print the value in AL?
  : Thanks for any help.
  :
  : [code]:
  : ORG 100h
  :
  : Set:
  : mov sp,8000h ;set stack
  : mov ax,0002h ;select mode 02h display monitor
  : int 10h ;BIOS sets mode via int 10h
  : mov ah,01h ;set half size cursor
  : mov cx,0006h
  : int 10h ;BIOS sets half size cursor
  :
  : poll:
  : mov ah,02h ;position cursor on page 0
  : mov bh,00h ;cursor on page 0
  : mov dx,0c25h ;position on row 12, column 37
  : int 10h ;cursor positioned
  : mov ah,00h ;get the key ASCII code in AL
  :
  : int 16h ;ENTER A '4' FOR TESTING PURPOSES
  :
  : mov dl,al ;store for later use
  : cmp ah,01h ;stop if Esc key hit
  : jne screen ;if not then display key
  : mov ax,4c00h ;if yes back to DOS
  : int 21h
  :
  : screen:
  : mov ah,09h ;display character function
  : mov bh,00h ;page 0
  : mov bl,1fh ;white character, blue background
  : mov cx, 0001h ;one character
  :
  : ;HOW DO I DISPLAY '34' THE VALUE THAT'S IN AL?
  :
  : int 10h ;display it
  : jmp poll ;next character
  : [/code]:
  
  Here's some C++ code that does what you want:
  [code]
  char* arr = "0123456789ABCDEF";
  out << arr[al&0xf];
  out << arr[al&0xff>>4];
  [/code]
  
  Use the same principle.
• bridger31

  August 2007

  Thanks for the reply, but it is not the principle I am having trouble with whereas I have some experience w/ C/C++ as well. I am specifically looking for instruction help on how to display the value of AL which is a hex value using the function 01h method. Please see initial post for description of what I am looking for - thanks for the effort!
  
• IDK

  August 2007

  : Thanks for the reply, but it is not the principle I am having
  : trouble with whereas I have some experience w/ C/C++ as well. I am
  : specifically looking for instruction help on how to display the
  : value of AL which is a hex value using the function 01h method.
  : Please see initial post for description of what I am looking for -
  : thanks for the effort!
  :
  
  Yes, and I described how to do it in a psuedo way.
  
  You'll need to output two chars, as becouse you want to do that. And you get the different chars by using the technique described above.
  
  al&0xf is simply and al,0xf in asm.
  and al >> 4, is simply shr ax,4
  and 'indexing' is done by adding, like this:
  hexChars: db "0123456789ABCDEF"
  mov [hexChars+al]
  
  All simple things in C is simple in assembly (this isn't really true, but almost).
  
  Now I've written you almost everything.
  
  And I did make a mistake in my previus post, the second output line should be:
  [code]
  out << arr[al>>4];
  [/code]
• Bulldog_466

  September 2007

  : I am looking for guidance on how to print the hex value of a number
  : entered from the keyboard. Enter a value when prompted, for comment
  : consistency enter the number 4. I want that number 4 to display the
  : cooresponding value in hex. IE, enter 4 on keyboard, print 34 on
  : the screen. The value I want to print is located in AL, but I can
  : only display the enter value of 4. How do I print the value in AL?
  : Thanks for any help.
  :
  : [code]:
  : ORG 100h
  :
  : Set:
  : mov sp,8000h ;set stack
  : mov ax,0002h ;select mode 02h display monitor
  : int 10h ;BIOS sets mode via int 10h
  : mov ah,01h ;set half size cursor
  : mov cx,0006h
  : int 10h ;BIOS sets half size cursor
  :
  : poll:
  : mov ah,02h ;position cursor on page 0
  : mov bh,00h ;cursor on page 0
  : mov dx,0c25h ;position on row 12, column 37
  : int 10h ;cursor positioned
  : mov ah,00h ;get the key ASCII code in AL
  :
  : int 16h ;ENTER A '4' FOR TESTING PURPOSES
  :
  : mov dl,al ;store for later use
  : cmp ah,01h ;stop if Esc key hit
  : jne screen ;if not then display key
  : mov ax,4c00h ;if yes back to DOS
  : int 21h
  :
  : screen:
  : mov ah,09h ;display character function
  : mov bh,00h ;page 0
  : mov bl,1fh ;white character, blue background
  : mov cx, 0001h ;one character
  :
  : ;HOW DO I DISPLAY '34' THE VALUE THAT'S IN AL?
  :
  : int 10h ;display it
  : jmp poll ;next character
  : [/code]:
  
  
  My code is not perfect but you get the idea
  
  
  
  Set:
  push cs
  pop ds
  mov sp,8000h ;set stack
  mov ax,0002h ;select mode 02h display monitor
  int 10h ;BIOS sets mode via int 10h
  mov ah,01h ;set half size cursor
  mov cx,0006h
  int 10h ;BIOS sets half size cursor
  
  poll:
  mov dx,0c25h ;position on row 12, column 37
  call set_cursor
  
  mov ah,00h ;get the key ASCII code in AL
  int 16h ;ENTER A '4' FOR TESTING PURPOSES
  
  mov dl,al ;store for later use
  cmp ah,01h ;stop if Esc key hit
  jne screen ;if not then display key
  mov ax,4c00h ;if yes back to DOS
  int 21h
  
  screen:
  mov bx,offset cs:charBuff
  xor ah,ah
  call Hexasc
  mov si,offset cs:charBuff
  mov dx,0c25h ;position on row 12, column 37
  nxtchar:
  call set_cursor
  push dx
  
  mov ah,09h ;display character function
  mov bh,00h ;page 0
  mov bl,1fh ;white character, blue background
  mov cx, 0001h ;one character
  
  
  lodsb
  int 10h
  pop dx
  inc dl
  or al,al
  jnz nxtchar
  
  jmp poll ;next character
  
  
  
  Hexasc proc near
  ;call with:
  ; ax=hex value
  ; ds:bx = address of buffer
  
  push cx
  push dx
  mov dx,4
  
  Hexasc1:
  mov cx,4
  rol ax,cl
  mov cx,ax
  and cx,0fh
  add cx,'0'
  cmp cx,'9'
  jbe hexasc2
  
  add cx,'A'-'9'-1
  
  
  Hexasc2:
  mov [bx],cl
  inc bx
  dec dx
  jnz Hexasc1
  pop dx
  pop cx
  ret
  
  Hexasc endp
  
  set_cursor proc near
  
  mov ah,02h ;position cursor on page 0
  mov bh,00h ;cursor on page 0
  int 10h ;cursor positioned
  ret
  set_cursor endp
  
  charBuff db 5 dup(0)