/*

    File:       AsyncSCSIPresent.c

    Contains:   

    Written by:     

    Copyright:  Copyright © 1992-1999 by Apple Computer, Inc., All Rights Reserved.

                You may incorporate this Apple sample source code into your program(s) without

                restriction. This Apple sample source code has been provided "AS IS" and the

                responsibility for its operation is yours. You are not permitted to redistribute

                this Apple sample source code as "Apple sample source code" after having made

                changes. If you're going to re-distribute the source, we require that you make

                it clear in the source that the code was descended from Apple sample source

                code, but that you've made changes.

    Change History (most recent first):

                7/14/1999   Karl Groethe    Updated for Metrowerks Codewarror Pro 2.1

*/

#include <OSUtils.h>

#include <Traps.h>

#ifndef _SCSIAtomic

/*

 * This is needed if you don't have Universal Headers.

 */

#define _SCSIAtomic 0xA089

#endif

Boolean                     AsyncSCSIPresent(void);

static Boolean              TrapAvailable(

        short                   theTrap

    );

Boolean

AsyncSCSIPresent(void)

{

        return (TrapAvailable(_SCSIAtomic));

}

/*

 * TrapAvailable (see Inside Mac VI 3-8)

 */

#define NumToolboxTraps() (                             \

        (NGetTrapAddress(_InitGraf, ToolTrap)           \

                == NGetTrapAddress(0xAA6E, ToolTrap))   \

            ? 0x200 : 0x400                             \

    )

#define GetTrapType(theTrap) (                          \

        (((theTrap) & 0x0800) != 0) ? ToolTrap : OSTrap \

    )

static Boolean

TrapAvailable(

        short                   theTrap

    )

{

        TrapType                trapType;

        trapType = GetTrapType(theTrap);

        if (trapType == ToolTrap) {

            theTrap &= 0x07FF;

            if (theTrap >= NumToolboxTraps())

                theTrap = _Unimplemented;

        }

        return (

            NGetTrapAddress(theTrap, trapType)

            != NGetTrapAddress(_Unimplemented, ToolTrap)

        );

}