/*
* Initializes the system's clock.
*/
PUBLIC void clock_init(unsigned freq)
{
uint16_t freq_divisor;
kprintf("dev: initializing clock device driver");
set_hwint(INT_CLOCK, &do_clock);
freq_divisor = PIT_FREQUENCY/freq;
/* Send control byte: adjust frequency divisor. */
outputb(PIT_CTRL, 0x36);
/* Send data byte: divisor_low and divisor_high. */
outputb(PIT_DATA, (byte_t)(freq_divisor & 0xff));
outputb(PIT_DATA, (byte_t)((freq_divisor >> 8)));
}
/*
* Parses key hit and decodes it to a scan code.
*/
PRIVATE uint8_t parse_key_hit(void)
{
uint8_t scancode;
uint8_t port_value;
scancode = inputb(0x60);
port_value = inputb(0x61);
outputb(0x61, port_value | 0x80);
outputb(0x61, port_value & ~0x80);
/* A key was released. */
if(scancode & 0x80)
{
scancode &= 0x7F;
/* Parse scan code. */
switch (scancode)
{
/* Shift. */
case KRLEFT_SHIFT:
case KRRIGHT_SHIFT:
mode &= ~SHIFT;
break;
/* CTRL. */
case KRLEFT_CTRL:
mode &= ~CTRL;
break;
/* Any other. */
default:
mode &= ~ANY;
break;
}
}
/* A key was pressed. */
else
{
/* Parse scan code. */
switch (scancode)
{
/* Shift. */
case KRLEFT_SHIFT:
case KRRIGHT_SHIFT:
mode |= SHIFT;
break;
/* CTRL. */
case KRLEFT_CTRL:
mode |= CTRL;
break;
/* Any other. */
default:
mode |= ANY;
break;
}
}
return (scancode);
}