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cinterruptbios

BIOS interrupt _int86

I'm trying out some old code frome the book "Black art of 3d game programming". I know it is outdated but I started reading it and it's kind of fun and interesting. I downloaded the OpenWatcom C Compiler and made a new DOS Project in order to get this old code even compiled. I already compiled on piece of code where Videomode int13h is set and then I was able to draw pixels to the screen. But this was done with a C function called _setvideomode(). In the following example the videomode is set via the _int86 function which makes the interrupt call and the prototype should be in bios.h, but OpenWatcom says: No prototype found for function _int86. I am stuck now and don't know what to do ;) Here is the code: 

void setGraphxMode(int mode){
    union REGS inregs,outregs;

    inregs.h.ah = 0;
    inregs.h.al = (unsigned char)mode;

    _int86(0x10,&inregs,&outregs);
}

int main(){

    return 0;
}

Would appreciate any advise on this and yes I know: Graphics are done via DirectX or OpenGL these days. This is just for learning purpose! Thank you :)

Solution

  • Under OpenWatcom the call you are looking for is int386 I believe:

    int386(0x10, &inregs, &outregs);