n_keybrd.c

开放源码的编译器open watcom 1.6.0版的源代码

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*                            Open Watcom Project
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*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
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*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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#include "variety.h"
#include <dos.h>
#include <bios98.h>
#include "nonibm.h"

/*
 * FUNCTION: __nec98_bios_keybrd
 * DESCRIPTION: uses int 18h to access bios keyboard functions
 *      _KEYBRD_READ - read a byte from the keyboard buffer.
 *              -if no keystroke is available wait until one is
 *      _KEYBRD_READY - check if a keystroke is available
 *              -if one is return it without removing it from the buffer
 *      _KEYBRD_SHIFTSTATUS - get the status of the shift keys
 *      _KEYBRD_INITIALIZE - initialize the keyboad buffer
 *      _KEYBRD_INPUTSTATUS - get status of the 16 key groups
 *
 *      The parameter __buf is ignored except for _KEYBRD_INPUTSTATUS
 *
 * RETURNS:
 * _KEYBRD_READ - ASCII value in low byte
 *              - Scan Code in high byte
 * _KEYBRD_READY - 0 if no character in buffer
 *               - same as _KEYBRD_READ otherwise
 * _KEYBRD_SHIFTSTATUS - low order 5 bits are significant
 *                      - bit 0         shift key pressed
 *                      - bit 1         caps key pressed
 *                      - bit 2         kana key pressed
 *                      - bit 3         graph key pressed
 *                      - bit 4         ctrl key pressed
 * _KEYBRD_INITIALIZE - no meaningful return value
 * _KEYBRD_INPUTSTATUS - status of the 16 key groups placed in __buf
 */

_WCRTLINK unsigned short __nec98_bios_keybrd( unsigned __cmd, unsigned char * __buf )
{
    union REGS r;
    int i;

    if( !__NonIBM )  return( 0 );       // fail if not a NEC 98 machine

#if defined(__386__)
    switch( r.h.ah = __cmd ) {
      case _KEYBRD_READ:
        int386( 0x18, &r, &r );
        break;
      case _KEYBRD_READY:
        int386( 0x18, &r, &r );
        if( !r.h.bh ) r.x.eax = 0;
        break ;
      case _KEYBRD_SHIFTSTATUS:
        int386( 0x18, &r, &r );
        r.h.ah = 0;
        break;
      case _KEYBRD_INITIALIZE:
        int386( 0x18, &r, &r );
        break;
      default:
        for( i = 0; i < 16; i++ ){
            r.h.al = i;
            int386( 0x18, &r, &r );
            __buf[i] = r.h.ah;
        }
    }
    return r.w.ax;
#else
    switch( r.h.ah = __cmd ) {
      case _KEYBRD_READ:
        int86( 0x18, &r, &r );
        break;
      case _KEYBRD_READY:
        int86( 0x18, &r, &r );
        if( !r.h.bh ) r.w.ax = 0;
        break ;
      case _KEYBRD_SHIFTSTATUS:
        int86( 0x18, &r, &r );
        r.h.ah = 0;
        break;
      case _KEYBRD_INITIALIZE:
        int86( 0x18, &r, &r );
        break;
      default:
        for( i = 0; i < 16; i++ ){
            r.h.al = i;
            int86( 0x18, &r, &r );
            __buf[i] = r.h.ah;
        }
    }
    return r.w.ax;
#endif
}