mode13

This is a discussion on mode13 within the A Brief History of Cprogramming.com forums, part of the Community Boards category; I have attempted Denthor of Asphyxia tutorial on dos graphics[concerted to C++ by Snowman] and writing to graphics memory in ...

  1. #1
    Unregistered
    Guest

    mode13

    I have attempted Denthor of Asphyxia tutorial on dos graphics[concerted to C++ by Snowman] and writing to graphics memory in mode 13. I have tried to write inn some functions[C++] into my program which are given in the tutorial like:

    void SetMCGA()
    {
    _AX = 0x0013;
    geninterrupt (0x10);
    }

    and

    void INTPutpixel(int x, int y, unsigned char Col)
    {
    _AH = 0x0C;
    _AL = Col;
    _CX = x;
    _DX = y;
    _BX = 0x01;
    geninterrupt (0x10);
    }

    Functions like these are really all I need, but I can't get it to compile. Is there something obvious I'm missing. Do I need to include anything more than the dos.h etc...? Is the way assembly code implemented in C++ different in different compilers. I'm using the free C++Builder 5.5 from Borland. Have never ever really used assembly in my C++ code.
    If some friendly soul would please help me I would be very thankfull.
    Vennlig Hilsen
    August

  2. #2
    ....
    Join Date
    Aug 2001
    Location
    Groningen (NL)
    Posts
    2,386
    I think your compiler doesn't support geninterrupt (..) function. So you should search in your documentation which function you need to work with interrupts.

    Or you could use inline assemly. I'm not sure about the syntaxis, but I guess this could work.

    Code:
    void SetMCGA (void)
    {
        asm {
            mov ax,0x13
            int 0x10
        }
    }
    
    void INTPutpixel(int x, int y, unsigned char Col) 
    {
        asm {
            mov ah,0x0c
            mov al,col
            mov cx,x
            mov dx,y
            mov bx,0x01
            int 0x10
        }
    }

  3. #3
    Registered User
    Join Date
    Aug 2001
    Posts
    380
    Could the problem be that a dos compiler is required instead of a windows compiler?

  4. #4
    Super Moderator VirtualAce's Avatar
    Join Date
    Aug 2001
    Posts
    9,586
    Code:
    //include these 6 lines if you are using pure asm only, not inline
    extern "C"
    {
       void SetMode(void);
       void PlotPixel(int x,int y,unsigned char color,
                             unsigned char     *buffer);
       void CLS(unsigned char *buffer);
    }
    //end of extern block
    
    
    unsigned char *Screen;
    unsigned char *Buffer;
    
    int main(void)
    {
      
      Screen=(unsigned char *)MK_FP(0xa000,0);
      //Do the buffer here -> whatever you need
      SetMode13();
      CLS(Screen);
      PlotPixel(x,y,15,Screen);
    
    
      getch();    //So we can see if it works
    }


    Here is what the pure asm file will look like if you opt for that

    In pure assembly using TASM
    Code:
    .MODEL large
    .CODE
    
    public _CLS,_PlotPixel,_SetMode
    
    _SetMode          PROC
    
    mov         ax,013h
    int           10h
    
    ret
    
    _SetMode          ENDP
    
    _CLS                   PROC
    ARG  buffer:DWORD
    
    push        bp                    
    mov         bp,sp               ;housekeeping for C and ARG
    push       di                      ;just in case preserve DI
    
    les           di,buffer           ;load full pointer into ES:DI
    mov         al,color            ;load color in AL
    mov         cx,0FA00h        ;prepare to block fill 64000 bytes
    rep          stosb                ;do it 
    
    pop         di                      ;restore DI
    pop         bp                    ;restore bp for C
    ret                                   ;return to caller
    
    _CLS                ENDP
    
    _PlotPixel           PROC
    ARG x:WORD,y:WORD,color:BYTE,buffer:DWORD
    
    push      bp
    mov       bp,sp
    
    mov       ax,SEG buffer
    mov       es,ax
    mov       ax,y
    shl         ax,6
    mov       bx,y
    shl         bx,8
    add       bx,ax
    add       bx,x
    mov      al,color
    
    mov es:[bx],al
    
    pop       bp
    
    ret
    _PlotPixel         ENDP
    
    
    END

    In C using inline assembly
    Code:
    void SetMode(void)
    {
      union REG regs;
      regs.x.ax=0x13;
      int86(0x10,& regs,& regs);
      
      //or
      // asm {
      //   mov   ax,013h
      //   int 10h
      // }
    
    }
    
    void PlotPixel(int x,int y,unsigned char *color,
                          unsigned char *buffer)
    {
    
      asm  {
        mov       ax,SEG buffer
        mov       es,ax
        mov       ax,y
        shl         ax,6 
        mov       bx,y
        shl         bx,8
        add       bx,ax
        add       bx,x
        mov      al,color
    
        mov es:[bx],al
     }
    }
    
    void CLS(unsigned char *buffer)
    {
      asm {
        push di
    
        les           di,buffer             
        mov         al,color            
        mov         cx,0FA00h        
        rep          stosb                 
       
        pop di
      }
    }
    Incidentally do not use geninterrupt() as it does not preserve the registers. Use the int86(), and int86x() family of functions if you are doing interrupts from C.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Help with mode13 with djgpp on win XP
    By Marcos in forum Game Programming
    Replies: 5
    Last Post: 10-17-2005, 12:00 AM
  2. Borland 5.5 - Graphics??
    By Jamazon in forum C++ Programming
    Replies: 1
    Last Post: 11-08-2001, 01:51 AM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21