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 }
  26
  27