[Dev-C++] Where are int86() and union REGS?

[James D. <sem...@ho...>]

Hello.
I have been trying to program some low-level graphics routines for a console 
application. All of the
C++ books I have read have used the data structure union REGS to represent 
the registry, and
functions such as int86(), outport, etc. etc. (included in dos.h). This 
header may be obsolete, or
a Borland extension of C++ - I don't know. I turned to assembly to 
accomplish the same function,
but the code shown below resulted in the Blue Screen of Death when the 'int' 
command was
called.

int mode = -1;

void SetVideoMode (int local_mode)
{
    // This function consists of two parts: firstly, it saves the current
    // video mode in the global variable oldmode, and secondly, it loads
    // various values into the registry and calls the Video BIOS interrupt
    // for changing screen mode.

    mode = local_mode;

    asm( "movb $0xF,%ah"         );          // The BIOS interrupt to return
                                                         // the video mode.
    asm( "int $0x10"            );                // The Video BIOS 
interrupt.
    asm( "movb %al,_oldmode"     );        // Stick the mode value (in %al)
                                                         // into the 
variable oldmode.    */

    // The old mode has been retrieved, now all that needs to be done is the
    // actual mode changing.

    asm( "movb $0x0,%ah"         );          // Interrupt 0h - Screen mode.
    asm( "movb _mode,%al"        );         // Put the mode into %al
    asm( "int $0x10"            );                // Video BIOS interrupt.
}

I have never been very good at assembly, but this code has been terribly 
hard to debug. Does anyone
know if a new version of the dos.h functions exists for Dev-C++, or how to 
use assembly to the
same extent?

Gratefully,
From the Assembly-Migraine afflicted.

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