src/devices/input.c

   1 #include "devices/input.h"
   2 #include <debug.h>
   3 #include "devices/intq.h"
   4 #include "devices/serial.h"
   5
   6 /* Stores keys from the keyboard and serial port. */
   7 static struct intq buffer;
   8
   9 /* Initializes the input buffer. */
  10 void
  11 input_init (void)
  12 {
  13   intq_init (&buffer);
  14 }
  15
  16 /* Adds a key to the input buffer.
  17    Interrupts must be off and the buffer must not be full. */
  18 void
  19 input_putc (uint8_t key)
  20 {
  21   ASSERT (intr_get_level () == INTR_OFF);
  22   ASSERT (!intq_full (&buffer));
  23
  24   intq_putc (&buffer, key);
  25   serial_notify ();
  26 }
  27
  28 /* Retrieves a key from the input buffer.
  29    If the buffer is empty, waits for a key to be pressed. */
  30 uint8_t
  31 input_getc (void)
  32 {
  33   enum intr_level old_level;
  34   uint8_t key;
  35
  36   old_level = intr_disable ();
  37   key = intq_getc (&buffer);
  38   serial_notify ();
  39   intr_set_level (old_level);
  40
  41   return key;
  42 }
  43
  44 /* Returns true if the input buffer is full,
  45    false otherwise.
  46    Interrupts must be off. */
  47 bool
  48 input_full (void)
  49 {
  50   ASSERT (intr_get_level () == INTR_OFF);
  51   return intq_full (&buffer);
  52 }