com32/menu/drain.c

   1 #include <stdio.h>
   2 #include <unistd.h>
   3 #include <errno.h>
   4 #include <string.h>
   5 #include <sys/cpu.h>
   6
   7 void drain_keyboard(void)
   8 {
   9     /* Prevent "ghost typing" and keyboard buffer snooping */
  10     volatile char junk;
  11     int rv;
  12
  13     do {
  14         rv = read(0, (char *)&junk, 1);
  15     } while (rv > 0);
  16
  17     junk = 0;
  18
  19     cli();
  20     *(volatile uint8_t *)0x419 = 0;     /* Alt-XXX keyboard area */
  21     *(volatile uint16_t *)0x41a = 0x1e; /* Keyboard buffer empty */
  22     *(volatile uint16_t *)0x41c = 0x1e;
  23     memset((void *)0x41e, 0, 32);       /* Clear the actual keyboard buffer */
  24     sti();
  25 }