static int32_t Receive_Byte (uint8_t *c, uint32_t timeout)
{
u8 temp8;
while(timeout-- > 0)
{
if(GetUart(&temp8) == 1)
{
*c = temp8;
return 0;
}
}
return -1;
}
void InitPort (void)
{
int mcr;
int temp;
if(port_initted)
return;
//
// Reset the output queue
//
outque.head = outque.tail = 0;
//
// find the irq and io address of the port
//
GetUart ();
//
// init com port settings
//
regs.x.ax = 0xf3; //f3= 9600 n 8 1
regs.x.dx = comport - 1;
int86 (0x14, ®s, ®s);
//
// check for a 16550
//
OUTPUT(uart + FIFO_CONTROL_REGISTER, FCR_FIFO_ENABLE + FCR_TRIGGER_04);
temp = INPUT(uart + INTERRUPT_ID_REGISTER);
if ((temp & 0xf8) == 0xc0)
{
uart_type = UART_16550;
usermsg ("UART is a 16550");
}
else
{
uart_type = UART_8250;
OUTPUT(uart + FIFO_CONTROL_REGISTER, 0);
usermsg("UART is an 8250");
}
//
// prepare for interrupts
//
OUTPUT(uart + INTERRUPT_ENABLE_REGISTER, 0);
mcr = INPUT(uart + MODEM_CONTROL_REGISTER);
mcr |= MCR_OUT2;
mcr &= ~MCR_LOOPBACK;
OUTPUT(uart + MODEM_CONTROL_REGISTER, mcr);
INPUT(uart); // Clear any pending interrupts
INPUT(uart + INTERRUPT_ID_REGISTER);
//
// hook the irq vector
//
irqintnum = irq + 8;
asm("cli"); // disable interrupts
_go32_dpmi_get_protected_mode_interrupt_vector(irqintnum, &oldirqvect);
newirqvect.pm_offset = (int)isr_8250;
newirqvect.pm_selector = _go32_my_cs();
_go32_dpmi_allocate_iret_wrapper(&newirqvect);
_go32_dpmi_set_protected_mode_interrupt_vector(irqintnum, &newirqvect);
asm("sti"); // enable interrupts
OUTPUT(0x20 + 1, INPUT(0x20 + 1) & ~(1<<irq));
asm("cli"); // disable again
// enable RX and TX interrupts at the uart
OUTPUT(uart + INTERRUPT_ENABLE_REGISTER,
IER_RX_DATA_READY + IER_TX_HOLDING_REGISTER_EMPTY);
// enable interrupts through the interrupt controller
OUTPUT(0x20, 0xc2);
// set DTR
OUTPUT(uart + MODEM_CONTROL_REGISTER
, INPUT(uart + MODEM_CONTROL_REGISTER) | MCR_DTR);
asm("sti"); // re-enable
port_initted = true;
}
