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开放源码的编译器open watcom 1.6.0版的源代码

	else
	    printf( "ASCII: yes\tChar: %c \t", ascii );
	printf( "Code: %.2X\tScan: %.2X\t Shift: %.4X\n",
						   ascii, scan, shift );
    }
}

------------------------------------------------------------------------------
  Include:  <bios.h>

  Syntax:   unsigned _bios_memsize(void);

  Returns:  Memory block size (unit:1K bytes)

  _bios_memsize checks the size of total main memory

  Return value

    It returns the size of the installed total main memory by 1 K block
    unit. The maximum size is 640, which means 640 K bytes.

/* SYSINFO.C illustrates miscellaneous DOS and BIOS status functions
 * including:
 *	_dos_getdrive	    _dos_setdrive	_dos_getdiskfree
 *	_bios_memsize	    _bios_equiplist	_bios_printer
 *							       (DOS-only)
 * See DISK.C for another example of _dos_getdiskfree.
 *
 * Also illustrated:
 *	union		    bitfield struct
 */

#include <dos.h>
#include <bios.h>
#include <conio.h>
#include <stdio.h>
#define LPT1 0

void main()
{
    struct diskfree_t drvinfo;
    unsigned drive, drivecount, memory, pstatus;
    union {			     /* Access equipment either as:  */
	unsigned u;		     /* unsigned or		    */
	struct {		     /* bit fields		    */
	    unsigned reserved1:1;    /* Reserved		    */
	    unsigned coprocessor:1;  /* Coprocessor?		    */
	    unsigned reserved2:1;    /* Reserved		    */
	    unsigned disks:5;	     /* Drives			    */
	    unsigned mouse:1;	     /* Mouse			    */
	    unsigned comports:3;     /* Serial ports		    */
	    unsigned gpib:1;	     /* GP-IB board		    */
	    unsigned sound:1;	     /* Sound board		    */
	    unsigned printers:2;     /* Number of printers	    */
	} bits;
    } equip;
    char    y[] = "YES", n[] = "NO";

    /* Get current drive. */
    _dos_getdrive( &drive );
    printf( "Current drive:\t\t\t%c:\n", 'A' + drive - 1 );

    /* Set drive to current drive in order to get number of drives. */
    _dos_setdrive( drive, &drivecount );

    _dos_getdiskfree( drive, &drvinfo );
    printf( "Disk space free:\t\t%ld\n",
	     ( long )drvinfo.avail_clusters *
	     drvinfo.sectors_per_cluster *
	     drvinfo.bytes_per_sector );

    /* Get new drive and number of logical drives in system. */
    _dos_getdrive( &drive );
    printf( "Number of logical drives:\t%d\n", drivecount );

    memory = _bios_memsize();
    printf( "Memory:\t\t\t\t%dK\n", memory );

    equip.u = _bios_equiplist();

    printf( "Disk drives:\t\t\t%d\n", equip.bits.disks );
    printf( "Coprocessor:\t\t\t%s\n", equip.bits.coprocessor ? y : n );
    printf( "Mouse driver:\t\t\t%s\n", equip.bits.mouse ? y : n );
    printf( "Serial ports:\t\t\t%d\n", equip.bits.comports );
    printf( "GP-IB interface:\t\t%s\n", equip.bits.gpib ? y : n );
    printf( "FM-sound:\t\t\t%s\n", equip.bits.sound ? y : n );
    printf( "Number of printers:\t\t%d\n", equip.bits.printers );

    /* Fail if any error bit is on, or if either operation bit is off. */
    pstatus = _bios_printer( _PRN_STATUS, 0 );
    if ( pstatus & 0x01 )
	pstatus = 0;
    else
	pstatus = 1;
    printf( "Printer available:\t\t%s\n", pstatus ? y : n );
}

------------------------------------------------------------------------------
  Include:  <bios.h>

  Syntax:   unsigned _bios_printer(unsigned service,
			unsigned char *databyte);

	    service: _PRN_INIT	_PRN_WRITE  _PRN_STRING  _PRN_STATUS

  Returns:  It is different depending on <service>.

  _bios_printer routine operates things specified by <service>.

One of the following symbol constants is specified in the argument  <service>.

    _PRN_INIT	    _PRN_STATUS     _PRN_WRITE	    _PRN_STRING

Return value

It is different depending on <service>. Please refer topics of each symbol constants

 Constant: _PRN_INIT	   _PRN_STATUS	   _PRN_STRING	   _PRN_WRITE

  Summary:  Constants of the argument <service> of _bios_printer

	    One of the below symbol constants is specified.

	    Constants		     The function of _bios_printer

	    _PRN_INIT		It initializes the status area and the controller.
				The bit 0 of the return value shows the following contents.

				Value  Meaning

				1   Enable to output data
				0   Disable to output data

	    _PRN_WRITE		It putout one byte of data from the area pointed to
				by the argument <data>.
				The bit 0 of the return value shows the following contents.

				Value  Meaning

				1   Complete to output data / Enable to output data
				0   Data is not output.

				The bit 0 of the return value shows the following contents.

				Value  Meaning

				1   Time out / The data is not output.
				0   Complete to output data

	    _PRN_STRING 	It output the data in the area pointed to
				by the argument <data> till the first null character.
				It returns zero if no errors and the number of characters
				which is not output if errors.

	    _PRN_STATUS 	It gets the status information of the printer.

				The bit 0 of the return value shows the following contents.

				Value  Meaning

				1   Enable to output data
				0   Disable to output data

/* SYSINFO.C illustrates miscellaneous DOS and BIOS status functions
 * including:
 *	_dos_getdrive	    _dos_setdrive	_dos_getdiskfree
 *	_bios_memsize	    _bios_equiplist	_bios_printer
 *							       (DOS-only)
 * See DISK.C for another example of _dos_getdiskfree.
 *
 * Also illustrated:
 *	union		    bitfield struct
 */

#include <dos.h>
#include <bios.h>
#include <conio.h>
#include <stdio.h>
#define LPT1 0

void main()
{
    struct diskfree_t drvinfo;
    unsigned drive, drivecount, memory, pstatus;
    union {			     /* Access equipment either as:  */
	unsigned u;		     /* unsigned or		    */
	struct {		     /* bit fields		    */
	    unsigned reserved1:1;    /* Reserved		    */
	    unsigned coprocessor:1;  /* Coprocessor?		    */
	    unsigned reserved2:1;    /* Reserved		    */
	    unsigned disks:5;	     /* Drives			    */
	    unsigned mouse:1;	     /* Mouse			    */
	    unsigned comports:3;     /* Serial ports		    */
	    unsigned gpib:1;	     /* GP-IB board		    */
	    unsigned sound:1;	     /* Sound board		    */
	    unsigned printers:2;     /* Number of printers	    */
	} bits;
    } equip;
    char    y[] = "YES", n[] = "NO";

    /* Get current drive. */
    _dos_getdrive( &drive );
    printf( "Current drive:\t\t\t%c:\n", 'A' + drive - 1 );

    /* Set drive to current drive in order to get number of drives. */
    _dos_setdrive( drive, &drivecount );

    _dos_getdiskfree( drive, &drvinfo );
    printf( "Disk space free:\t\t%ld\n",
	     ( long )drvinfo.avail_clusters *
	     drvinfo.sectors_per_cluster *
	     drvinfo.bytes_per_sector );

    /* Get new drive and number of logical drives in system. */
    _dos_getdrive( &drive );
    printf( "Number of logical drives:\t%d\n", drivecount );

    memory = _bios_memsize();
    printf( "Memory:\t\t\t\t%dK\n", memory );

    equip.u = _bios_equiplist();

    printf( "Disk drives:\t\t\t%d\n", equip.bits.disks );
    printf( "Coprocessor:\t\t\t%s\n", equip.bits.coprocessor ? y : n );
    printf( "Mouse driver:\t\t\t%s\n", equip.bits.mouse ? y : n );
    printf( "Serial ports:\t\t\t%d\n", equip.bits.comports );
    printf( "GP-IB interface:\t\t%s\n", equip.bits.gpib ? y : n );
    printf( "FM-sound:\t\t\t%s\n", equip.bits.sound ? y : n );
    printf( "Number of printers:\t\t%d\n", equip.bits.printers );

    /* Fail if any error bit is on, or if either operation bit is off. */
    pstatus = _bios_printer( _PRN_STATUS, 0 );
    if ( pstatus & 0x01 )
	pstatus = 0;
    else
	pstatus = 1;
    printf( "Printer available:\t\t%s\n", pstatus ? y : n );
}

------------------------------------------------------------------------------
  Include:  <bios.h>

  Syntax:   unsigned _bios_serialcom(unsigned service,
			unsigned port, struct com_t *serialcom);

	    service: _COM_COMMAND   _COM_GETDTL   _COM_INIT    _COM_INITX
		     _COM_RECEIVE   _COM_SEND	  _COM_STATUS

	    port:    _COM_CH1	_COM_CH2   _COM_CH3

  Returns:  It returns zero if no error, non-zero if error.
	    It is different in the structure com_t depending on <service>.

  _bios_serialcom routine operates serial ports by operations specified
  in <service>.  The argument <port> shows the operated serial port which
  is one of _COM_CH1,_COM_CH2 or _COM_CH3. The information for operation is
  specified in <serialcom> of the structure com_t.

One of the following symbol constants is specified in <service>.

    _COM_COMMAND   _COM_GETDTL	 _COM_INIT    _COM_INITX
    _COM_RECEIVE   _COM_SEND	 _COM_STATUS

Return value

It returns zero if no errors, non-zero if errors. The value stored in
the structure com_t is different depending on <service>. Please refer
topics about symbol constants.

 Constant: _COM_COMMAND    _COM_GETDTL	   _COM_INIT	   _COM_INITX
	    _COM_RECEIVE    _COM_SEND	    _COM_STATUS

  Summary:  Constants of the argument <service> of _bios_serialcom

	    One of the below symbol constants is specified.

	    Constants		     The function of _bios_serialcom

	    _COM_COMMAND    It outputs the command information.
			   It uses the field command of the structure com_t only.

	    _COM_GETDTL     It gets the data length of the valid data in the receive buffer.
			    The received data length is stored in the field size of the structure com_t.

	    _COM_INIT	    It initializes the serial port specified in the argument <port>.
			    It uses all fields of the structure com_t.
			    When _COM_CH2 or _COM_CH3 is specified in the argument <port>,
			    the field baud of the structure com_t is ignored.

	    _COM_INITX	    It is the same function as _COM_INIT
			    except it can set X parameter ( flow control ).

	    _COM_RECEIVE    It received data. It stores the received data
			    in the field buffer+0, the status in buffer+1 if no errors.

	    _COM_SEND	    It sends one byte of data in the field buffer
			    of the structure com_t

	    _COM_STATUS     It gets the status of the controller and the system port.
			    It stores the information of the controller information
			    in the field buffer+0 and the system port information
			    in the field buffer+1 of the structure com_t.

			    The controller information is the following.

			    Bit  Meaning  In the case of 1  In the case of  0

			    0	 Send status	      Ready	  Busy
			    1	 Receive status       Ready	  Busy
			    2	 Send buffer	      Empty	  Full
			    3	 Parity error	      Error	  No error
			    4	 Overrun error	      Error	  No error
			    5	 Framing error	      Error	  No error
			    6	 Detect break status  Detect	  Not detect
			    7	 Data set ready       On	  Off

			    The system port information is is the following.

			    Bit  Meaning		   1	       0

			    0-4  Not used
			    5	 Received carrier detect  Not detect  Detect
			    6	 Send			  Disable     Enable
			    7	 Receive		  No	      Yes

  Structure:

  struct com_t
  {
		 unsigned baud; 	 /* Baud rate		*/
		 unsigned mode; 	 /* Mode set	       */
		 unsigned command;	 /* Command specified	      */
		 unsigned tx_time;	 /* The period od time out to send */
		 unsigned rx_time;	 /* The period od time out to receive */
		 unsigned size; 	 /* Buffer size to receive   */
		 void _far *buffer;	 /* Pointer to receive buffer	      */
  };

/* COM.C illustrates serial port access using function:
 *	_bios_serialcom 					(DOS-only)
 */

#include <bios.h>
#include <stdio.h>

void main()
{
    unsigned  status;

    status = _bios_serialcom( _COM_STATUS, _COM_CH1, 0 );

    /*
     * Report status of serial port and test whether there is a
     * responding device (such as a modem) for each. If data-set-ready
     * and clear-to-send bits are set, a device is responding.
     */
    printf( "COM status: %.4X\tActive: %s\n",
	   status, ( status & 0x0003 ) ? "YES" : "NO" );
}

------------------------------------------------------------------------------
  Include:  <bios.h>

  Syntax:   unsigned _bios_timeofday(unsigned service, char *timeval);

	    service: _TIME_GETCLOCK  _TIME_SETCLOCK

  Returns:  It returns zero if no errors, non-zero if errors

  _bios_timeofday routine gets or sets system clocks. _TIME_GETCLOCK or
  _TIME_SETCLOCK is specified in the argument <service>.

the area pointed by  the argument  <timeval> specifies to get or set
the system clock. This area is assigned like the below.

    timeval+0	Year (BCD 00-99)
    timeval+1	The upper 4 bit is month   ( 1-12 hex)
		The lower 4 bits is day ( 0-6 hex)
    timeval+2	date (BCD 1-31)
    timeval+3	hours (BCD 0-23)
    timeval+4	minutes (BCD 0-59)
    timeval+5	seconds (BCD 0-59)

Return value

It returns zero if no errors, non-zero if errors.

/* SIEVE.C illustrates timing functions including:
 *	clock		difftime	    _bios_timeofday
 *
 * In addition to the timing use shown here, these functions can be
 * used for delay loops as shown for the clock function
 * in BEEP.C.
 */

#include <time.h>
#include <stdio.h>
#include <bios.h>
#define TICKPERSEC	18.2

int	mark[ 10000 ];

void main()
{
    time_t   tstart, tend;    /* For difftime	      */
    clock_t  cstart, cend;    /* For clock	      */
    long     bstart, bend;    /* For _bios_timeofday  */
    register int i, loop;
    int      n, num, step;

    /* Start timing. */
    printf( "Working...\n" );
    time( &tstart );  /* Use time and difftime for timing to seconds   */
    cstart = clock(); /* Use clock for timing to hundredths of seconds */
#if defined( DOS )    /* Define DOS to use _bios_timeofday	       */
    _bios_timeofday( _TIME_GETCLOCK, &bstart );
#endif
    /* Do timed Sieve of Erotosthenes. */
    for ( loop = 0; loop < 250; ++loop )
	for ( num = 0, n = 3; n < 10000; n += 2 )
	    if ( !mark[ n ] ) {
		step = 2 * n;
		for ( i = 3 * n; i < 10000; i += step )
		    mark[ i ] = -1;
		++num;
	    }
    /*
     * End timing and print results. Note that _bios_timeofday doesn't
     * handle midnight rollover.
     */
    time( &tend );
    printf( "\ndifftime:\t\t%4.2f seconds to find %d primes 50 times\n",
	     difftime( tend, tstart ), num );
    cend = clock();
    printf( "\nclock:\t\t\t%4.2f seconds to find %d primes 50 times\n",
	     ( ( float )cend - cstart ) / CLK_TCK, num );

#if defined( DOS )
    _bios_timeofday( _TIME_GETCLOCK, &bend );
    printf( "\n_bios_timeofday:\t%4.2f seconds",
	     ( ( float )bend - bstart ) / TICKPERSEC );
    printf( " to find %d primes 50 times\n", num );

#endif
}