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Listing 3

/// VANYDEVDc.c

// --------------------------------------------

// Dynamically loadable VxD for ANYDEV board

// --------------------------------------------

#define WIN32_LEAN_AND_MEAN // Excludes un-needed parts of windows.h

#include "windows.h"

#include <e:\ddk95\inc32\vmm.h>

#include <e:\ddk95\inc32\vwin32.h>

#include <e:\ddk95\inc32\debug.h>

#include "VANYDEVD.H"





// -------------------------------------

// Externs defined in assembly module 

// -------------------------------------

// These defined in assembly for the VMM.INC or VPICD.INC file inclusion

extern DWORD GET_BD_MEM(void);

extern DWORD Virt_IRQ(void);

extern DWORD Get_IRQ_Status(void);

extern void UNVirt_IRQ(DWORD IRQhandle);

extern void End_ISR(DWORD IRQhandle);

extern void Physically_Mask_IRQ(DWORD IRQhandle);

extern void Physically_UNMask_IRQ(DWORD IRQhandle);





// ------------------------

// PRAGMA for this DATA 

// ------------------------

// Establish segment

#pragma data_seg ( "_LDATA","_LCODE")





// ------------------------------------

// Data structures MUST be INITIALIZED

// ------------------------------------

ADEV ANYDEVX = {0}; // Main structure for ANYDEV -- shared by app 





// ------------------------

// PRAGMAS for this CODE 

// ------------------------

// Establish segment

#pragma code_seg ( "_LTEXT", "_LCODE" )

//No stack checking for routines in this module

#pragma check_stack(off)





// ----------------

// Disable hardware

// ----------------

void Disable_AnyDev(void)

{

	//This would likely be a port WRITE to DISABLE the board's interrupt	 		

}





// ----------------

// Enable hardware

// ----------------

void Enable_AnyDev(void)

{

	//This would likely be a port WRITE to ENABLE the board's interrupt	 		

}

// --------------------------

// ISR Processing for ANYDEV

// --------------------------

void Process_ISR(void)

{

	//This is where the user might SET FLAGS and indicators in the ANYDEVX structure

	//in order to notify the application that data is available below 1MB	 		

}





// -----------------

// ISR for ANYDEV

// -----------------

void _declspec(naked)ISR_ANYDEV(void)

{

	// Save registers

	_asm sti

	_asm pushad

	_asm pushfd





	//Process the ISR 

	Process_ISR();





	//End ISR

	_asm clc

	End_ISR(ANYDEVX.IRQhandle);





	//Set GOOD return code

	_asm clc





	//Restore saved registers

	_asm popfd

	_asm popad

	_asm ret;

}





// -------------------

// Virtualize the IRQ

// -------------------

DWORD CVirt_IRQ(void)

{

	// If in use by an instance of this program, RETURN with BAD code

	if (ANYDEVX.IRQcount)

		return (BOGUSADDRESS);





	// If in use by another program, RETURN with BAD code

	ANYDEVX.IRQstatus = Get_IRQ_Status();

	if (ANYDEVX.IRQstatus)

		return (BOGUSADDRESS);





	// If IRQ NOT in use this point is reached

	// Set BAD return code

	ANYDEVX.IRQhandle = BOGUSADDRESS;

	// Disable ANYDEV hardware	

	Disable_AnyDev();

	// Get global memory address below 1mb

	ANYDEVX.Global_addr_1MB = GET_BD_MEM();

	if (ANYDEVX.Global_addr_1MB != BOGUSADDRESS)

		{

		// Virtualize the IRQ

		ANYDEVX.IRQhandle = Virt_IRQ();	

		if (ANYDEVX.IRQhandle != BOGUSADDRESS)

			{

			// unmask the IRQ, set OK flag & increment IRQ count

	 		Physically_UNMask_IRQ(ANYDEVX.IRQhandle);

	 		ANYDEVX.IRQflags |= IRQ_VIRT_OK;

			++(ANYDEVX.IRQcount);

			}

		}

	return(ANYDEVX.IRQhandle);

}

// ----------------------

// UN Virtualize the IRQ

// ----------------------

void CUNVirt_IRQ(DWORD IRQhandle)

{

 // if IRQ has been successfully virtualized

 if ((ANYDEVX.IRQhandle != 0)

 &&  (ANYDEVX.IRQhandle != BOGUSADDRESS))

 	{

	// Physically mask the IRQ and UN virtualized it

	Physically_Mask_IRQ(ANYDEVX.IRQhandle);

	UNVirt_IRQ(ANYDEVX.IRQhandle);

	}

// Set UNvirtualized flags and indicators

ANYDEVX.IRQhandle = BOGUSADDRESS;

ANYDEVX.IRQflags &= ~IRQ_VIRT_OK;

	return;

}





// ---------------------------------------

// Set Good Return code for DIOC requests

// ---------------------------------------

void _declspec(naked)GoodReturnDIOC(void)

{

	// Clear eax and carry flag for GOOD return

	_asm xor eax,eax

	_asm clc

	_asm ret;

}





// ---------------------------------------

// Set Bad Return code for DIOC requests

// ---------------------------------------

void _declspec(naked) BadReturnDIOC(void)

{

	// NOTE: 50 is a FCN NOT SUPPORTED code -- ok to use

	// SET carry flag for BAD return

	_asm mov eax,50

	_asm stc

	_asm ret;

}









// ------------------------------

// Routine for ANYDEV Device UNINIT  

// ------------------------------

void CVANYDEVD_Device_UNInit()

{

// Disable ANYDEV, Unvirtualize IRQ, set GOOD return code

	Disable_AnyDev();			

	CUNVirt_IRQ(ANYDEVX.IRQhandle);	

	GoodReturnDIOC();			

	return;

}

// ------------------------------

// Routine for ANYDEV Device INIT  

// ------------------------------





void CVANYDEVD_Device_Init()

{

DWORD retcode;





	// Try to virtualize the IRQ

	retcode = CVirt_IRQ();

	// Set GOOD or BAD return code based on success

	if (retcode == BOGUSADDRESS)

		BadReturnDIOC();

	else

	    GoodReturnDIOC();

	return;

}

// --------------------------------

// Routine for ANYDEV Device IO ctrl  

// --------------------------------

void CVANYDEVD_Device_IOctrl(PDIOCPARAMETERS ptr)

{

DWORD *obuf1;

	// Field the DEV IO requests from VMM

	switch(ptr->dwIoControlCode)

		{

		case(VANYDEVD_INIT_ADEV_HARDWARE):

			ANYDEVX.flags = 0;

			//User likely to require other initialization here

		break;

		case(VANYDEVD_GRAB_ADDRESSES):

			// Point to Output buffer

			obuf1 = (DWORD *) ptr->lpvOutBuffer;

			// Return GLOBAL 1MB addr, addr of data structure

			// and return indicators of IRQ virtuaization request

			*obuf1 = ANYDEVX.Global_addr_1MB;

		  	*(obuf1+1) = (DWORD) &ANYDEVX;

			*(obuf1+2) = (DWORD) ANYDEVX.IRQhandle;

			*(obuf1+3) = (DWORD) ANYDEVX.IRQflags;

			//User might want to return other/different values here

		break;

		case(VANYDEVD_ENABLE_ANYDEV_HDWR):

			//Call routine to enable interrupt

			Enable_AnyDev();

		break;

		case(VANYDEVD_DISABLE_ANYDEV_HWR):

			//Call routine to disable interrupt

			Disable_AnyDev();

		break;

		//The below DIOC_GETVERSION is a part of the dynamic load protocol

		//It MUST return a GOOD code (all codes here use GoodReturnDIOC()

		case(DIOC_GETVERSION):

		case(DIOC_CLOSEHANDLE):

		default:

		break;

		}

 	GoodReturnDIOC();

	return;

}