/*
 *  Listing 2  -  COM.H  -  "RS-232 Interrupts The C Way"
 *
 *  Copyright (C) Mark R. Nelson 1990
 *
 * This file contains the structure definitions, constants,
 * and function prototypes needed to use the RS-232
 * interface code supplied in COM.C.  It should be included
 * by any routine using COM.C procedures.
 */

/*
 * This structure defines the 256 byte buffer used for
 * I/O buffers by the COM routines.  By using a buffer
 * size of 256 bytes, updating the indices is simplified.
 */
typedef struct {
                 char buffer[256];
                 unsigned char write_index;
                 unsigned char read_index;
               } BUFFER;
/*
 * This structure defines a COM port.  It is initialized
 * when the port is opened with port_open().
 */
typedef struct {
                 void (interrupt far * old_vector)();
                 int                   uart_base;
                 int                   irq_mask;
                 int                   interrupt_number;
                 BUFFER                in;
                 BUFFER                out;
} PORT ;
/*
 * the ifdef M_186 is checking for Microsoft C/QuickC.
 * Borland and Microsoft differ slightly on the names of
 * some of the DOS specific procedure names, and the
 * fixing up is done here.
 */
#ifdef M_I86
#define inportb inp
#define outportb outp
#define getvect _dos_getvect
#define setvect _dos_setvect
#define enable _enable
#endif
/*
 * The fully qualified function prototypes.  All of these
 * routines actually reside in COM.C
 */
PORT *port_open( int address, int interrupt_number );
void port_set( PORT *port,
               long speed,
               char parity,
               int data,
               int stopbits );
void port_close( PORT *port );
int port_putc( unsigned char c, PORT *port );
int port_getc( PORT *port );
/*
 * These are the standard UART addresses and interrupt
 * numbers for the two IBM compatible COM ports.
 */
#define COM1_UART         0x3f8
#define COM1_INTERRUPT    12
#define COM2_UART         0x2f8
#define COM2_INTERRUPT    11