不是很明白?求解惑!!
static int parport_read(void)
{
int data = 0;
#if PARPORT_USE_PPDEV == 1
ioctl(device_handle, PPRSTATUS, & data);
#else
data = inb(statusport);
#endif
if ((data ^ cable->INPUT_INVERT) & cable->TDO_MASK)
return 1;
else
return 0;
}
static void parport_write(int tck, int tms, int tdi)
{
int i = wait_states + 1;
if (tck)
dataport_value |= cable->TCK_MASK;
else
dataport_value &= ~cable->TCK_MASK;
if (tms)
dataport_value |= cable->TMS_MASK;
else
dataport_value &= ~cable->TMS_MASK;
if (tdi)
dataport_value |= cable->TDI_MASK;
else
dataport_value &= ~cable->TDI_MASK;
while (i-- > 0)
parport_write_data();
}