template.c

/*
 * Template for writing DOS device drivers in Open Watcom C
 *
 * Copyright (C) 2022, Eduardo Casino (mail@eduardocasino.es)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 *
 */

#include <stdint.h>
#include <stddef.h>

#include "device.h"
#include "devinit.h"
#include "template.h"

#ifdef USE_INTERNAL_STACK

static uint8_t our_stack[STACK_SIZE];
uint8_t *stack_bottom = our_stack + STACK_SIZE;
uint32_t dos_stack;

#endif // USE_INTERNAL_STACK

request __far *fpRequest = (request __far *)0;

static uint16_t Open( void )
{
    return S_DONE;
}

static uint16_t Close( void )
{
    return S_DONE;
} 

static driverFunction_t dispatchTable[] =
{
    DeviceInit,          // 0x00 Initialize
    NULL,                // 0x01 MEDIA Check
    NULL,                // 0x02 Build BPB
    NULL,                // 0x03 Ioctl In
    NULL,                // 0x04 Input (Read)
    NULL,                // 0x05 Non-destructive Read
    NULL,                // 0x06 Input Status
    NULL,                // 0x07 Input Flush
    NULL,                // 0x08 Output (Write)
    NULL,                // 0x09 Output with verify
    NULL,                // 0x0A Output Status
    NULL,                // 0x0B Output Flush
    NULL,                // 0x0C Ioctl Out
    Open,                // 0x0D Device Open
    Close,               // 0x0E Device Close
    NULL,                // 0x0F Removable MEDIA
    NULL,                // 0x10 Output till busy
    NULL,                // 0x11 Unused
    NULL,                // 0x12 Unused
    NULL,                // 0x13 Generic Ioctl
    NULL,                // 0x14 Unused
    NULL,                // 0x15 Unused
    NULL,                // 0x16 Unused
    NULL,                // 0x17 Get Logical Device
    NULL,                // 0x18 Set Logical Device
    NULL                 // 0x19 Ioctl Query
};

static driverFunction_t currentFunction;

void __far DeviceInterrupt( void )
#pragma aux DeviceInterrupt __parm []
{
#ifdef USE_INTERNAL_STACK
    switch_stack();
#endif

    push_regs();

    if ( fpRequest->r_command > C_MAXCMD || NULL == (currentFunction = dispatchTable[fpRequest->r_command]) )
    {
        fpRequest->r_status = S_DONE | S_ERROR | E_CMD;
    }
    else
    {
        fpRequest->r_status = currentFunction();
    }

    pop_regs();

#ifdef USE_INTERNAL_STACK
    restore_stack();
#endif
}

void __far DeviceStrategy( request __far *req )
#pragma aux DeviceStrategy __parm [__es __bx]
{
    fpRequest = req;
}