Cobra Utilities for Doom & Doom II/Cobra Utilities For Doom & Doom II - Disc 2.iso/files/program/dmsrcc/port.c

C/C++ Source or Header | 1994-02-13 | 5.3 KB | 320 lines

// port.c

#include "doomnet.h"
#include "sersetup.h"

void jump_start( void );

void interrupt isr_8250 (void);

union    REGS    regs;
struct    SREGS    sregs;

que_t        inque, outque;


int            uart;            // io address
enum {UART_8250, UART_16550} uart_type;
int            irq;

int            modem_status = -1;
int            line_status = -1;

void interrupt (*oldirqvect) (void);
int            irqintnum;

int               comport;


/*
==============
=
= GetUart
=
==============
*/

void GetUart (void)
{
    char   far *system_data;
    static int ISA_uarts[] = {0x3f8,0x2f8,0x3e8,0x2e8};
    static int ISA_IRQs[] = {4,3,4,3};
    static int MCA_uarts[] = {0x03f8,0x02f8,0x3220,0x3228};
    static int MCA_IRQs[] = {4,3,3,3};
    int        p;

    if (CheckParm ("-com2"))
        comport = 2;
    else if (CheckParm ("-com3"))
        comport = 3;
    else if (CheckParm ("-com4"))
        comport = 4;
    else
        comport = 1;

    regs.h.ah = 0xc0;
    int86x( 0x15, ®s, ®s, &sregs );
    if ( regs.x.cflag )
    {
        irq = ISA_IRQs[ comport-1 ];
        uart = ISA_uarts[ comport-1 ];
        return;
    }
    system_data = ( char far *) ( ( (long) sregs.es << 16 ) + regs.x.bx );
    if ( system_data[ 5 ] & 0x02 )
    {
        irq = MCA_IRQs[ comport-1 ];
        uart = MCA_uarts[ comport-1 ];
    }
    else
    {
        irq = ISA_IRQs[ comport-1 ];
        uart = ISA_uarts[ comport-1 ];
    }

    p = CheckParm ("-port");
    if (p)
        scanf (_argv[p+1],"0x%x",&uart);
    p = CheckParm ("-irq");
    if (p)
        scanf (_argv[p+1],"%i",&irq);


    printf ("Looking for UART at port 0x%x, irq %i\n",uart,irq);
}




/*
===============
=
= InitPort
=
===============
*/

void InitPort (void)
{
    int mcr;
    int    temp;

//
// find the irq and io address of the port
//
    GetUart ();

//
// init com port settings
//
    regs.x.ax = 0xf3;        //f3= 9600 n 8 1
    regs.x.dx = comport - 1;
    int86 (0x14, ®s, ®s);


//
// check for a 16550
//
    OUTPUT( uart + FIFO_CONTROL_REGISTER, FCR_FIFO_ENABLE + FCR_TRIGGER_04 );
    temp = INPUT( uart + INTERRUPT_ID_REGISTER );
    if ( ( temp & 0xf8 ) == 0xc0 )
    {
        uart_type = UART_16550;
        printf ("UART is a 16550\n\n");
    }
    else
    {
        uart_type = UART_8250;
        OUTPUT( uart + FIFO_CONTROL_REGISTER, 0 );
        printf ("UART is an 8250\n\n");
    }

//
// prepare for interrupts
//
    OUTPUT( uart + INTERRUPT_ENABLE_REGISTER, 0 );
    mcr = INPUT( uart + MODEM_CONTROL_REGISTER );
    mcr |= MCR_OUT2;
    mcr &= ~MCR_LOOPBACK;
    OUTPUT( uart + MODEM_CONTROL_REGISTER, mcr );

    INPUT( uart );  // Clear any pending interrupts
    INPUT( uart + INTERRUPT_ID_REGISTER );

//
// hook the irq vector
//
    irqintnum = irq + 8;

    oldirqvect = getvect (irqintnum);
    setvect (irqintnum,isr_8250);

    OUTPUT( 0x20 + 1, INPUT( 0x20 + 1 ) & ~(1<<irq) );

    CLI();

// enable RX and TX interrupts at the uart

    OUTPUT( uart + INTERRUPT_ENABLE_REGISTER,
            IER_RX_DATA_READY + IER_TX_HOLDING_REGISTER_EMPTY);

// enable interrupts through the interrupt controller

    OUTPUT( 0x20, 0xc2 );

// set DTR
    OUTPUT( uart + MODEM_CONTROL_REGISTER
        , INPUT( uart + MODEM_CONTROL_REGISTER ) | MCR_DTR);


    STI();


}


/*
=============
=
= ShutdownPort
=
=============
*/

void ShutdownPort ( void )
{
    OUTPUT( uart + INTERRUPT_ENABLE_REGISTER, 0 );
    OUTPUT( uart + MODEM_CONTROL_REGISTER, 0 );

    OUTPUT( 0x20 + 1, INPUT( 0x20 + 1 ) | (1<<irq) );

    setvect (irqintnum,oldirqvect);

//
// init com port settings to defaults
//
    regs.x.ax = 0xf3;        //f3= 9600 n 8 1
    regs.x.dx = comport - 1;
    int86 (0x14, ®s, ®s);
}


int read_byte( void )
{
    int    c;

    if (inque.tail >= inque.head)
        return -1;
    c = inque.data[inque.tail%QUESIZE];
    inque.tail++;
    return c;
}


void write_byte( int c )
{
    outque.data[outque.head%QUESIZE] = c;
    outque.head++;
}



//==========================================================================


/*
==============
=
= isr_8250
=
==============
*/

void interrupt isr_8250(void)
{
    int c;
    int    count;

    while (1)
    {
        switch( INPUT( uart + INTERRUPT_ID_REGISTER ) & 7 )
        {
// not enabled
        case IIR_MODEM_STATUS_INTERRUPT :
            modem_status = INPUT( uart + MODEM_STATUS_REGISTER );
            break;

// not enabled
        case IIR_LINE_STATUS_INTERRUPT :
            line_status = INPUT( uart + LINE_STATUS_REGISTER );
            break;

//
// transmit
//
        case IIR_TX_HOLDING_REGISTER_INTERRUPT :
//I_ColorBlack (63,0,0);
            if (outque.tail < outque.head)
            {
                if (uart_type == UART_16550)
                    count = 16;
                else
                    count = 1;
                do
                {
                    c = outque.data[outque.tail%QUESIZE];
                    outque.tail++;
                    OUTPUT( uart + TRANSMIT_HOLDING_REGISTER, c );
                } while (--count && outque.tail < outque.head);
            }
            break;

//
// receive
//
        case IIR_RX_DATA_READY_INTERRUPT :
//I_ColorBlack (0,63,0);
            do
            {
                c = INPUT( uart + RECEIVE_BUFFER_REGISTER );
                inque.data[inque.head%QUESIZE] = c;
                inque.head++;
            } while ( uart_type == UART_16550 && INPUT( uart + LINE_STATUS_REGISTER ) & LSR_DATA_READY );

            break;

//
// done
//
        default :
//I_ColorBlack (0,0,0);
            OUTPUT( 0x20, 0x20 );
            return;
        }
    }
}


/*
===============
=
= jump_start
=
= Start up the transmition interrupts by sending the first char
===============
*/

void jump_start( void )
{
    int c;

    if (outque.tail < outque.head)
    {
        c = outque.data [outque.tail%QUESIZE];
        outque.tail++;
        OUTPUT( uart, c );
    }
}