www.pudn.com > supermary.rar > KEY.C

/* 
  file: KEY.C 
 
  purpose: 
    new keyboard interrupt handler and various keyboard routines 
    based on code from ZKEY.ASM 
 
  date: 11/4/95 
 
  note: 
    the key interrupts are not passed down or "chained" to the previous 
    interrupt handler. 
*/ 
#include 
#include 
#include 
 
#define KEYBOARD_PORT     0x60 
#define KEYBOARD_XT_CLEAR 0x61 
 
void far interrupt new_int09_handler(void); 
void far interrupt (*old_int09_handler)(); 
 
BYTER far *keybuf; 
 
static int new_key_handler_installed = FALSE; 
 
void install_new_key_handler(void) 
{ 
  keybuf = farmalloc(KEY_WAS_PRESSED * 2); 
  clear_key_buffer(); 
 
  old_int09_handler = getvect(9); 
  setvect(9, new_int09_handler); 
  new_key_handler_installed = TRUE; 
} 
 
void far interrupt new_int09_handler(void) 
{ 
  BYTER scan_code; 
  BYTER temp; 
 
  /* read scan code */ 
  scan_code = inportb(KEYBOARD_PORT); 
 
  /* clear keyboard controller on XT machines */ 
  temp = inportb(KEYBOARD_XT_CLEAR); 
  outportb(KEYBOARD_XT_CLEAR, temp | 0x80); 
  outportb(KEYBOARD_XT_CLEAR, temp & 0x7F); 
 
  if (scan_code & 0x80) { 
    /* key up */ 
    scan_code &= 0x7F; 
    keybuf[scan_code] = 0; 
  } 
  else { 
    /* key down */ 
    keybuf[scan_code] = 1; 
    keybuf[KEY_WAS_PRESSED+scan_code] = 1; 
  } 
 
  outportb(PIC, NONSPECIFIC_EOI); 
} 
 
void clear_key_buffer(void) 
{ 
  int i; 
  for (i = 0; i < KEY_WAS_PRESSED * 2; i++) 
    keybuf[i] = 0; 
} 
 
void uninstall_new_key_handler(void) 
{ 
  if (new_key_handler_installed) { 
    farfree(keybuf); 
    setvect(9, old_int09_handler); 
  } 
}