Function xs_serial_read

modules/io/serial/pico/serial.c:272–316

}

void xs_serial_read(xsMachine *the)
{
	Serial serial = xsmcGetHostDataValidate(xsThis, (void *)&xsSerialHooks);
	int available = fifo_length(&serial->rx_fifo);

	if (kIOFormatNumber == serial->format) {
		uint8_t byte;

		if (0 != fifo_get(&serial->rx_fifo, &byte))
			xsUnknownError("no data");

		xsmcSetInteger(xsResult, byte);
	}
	else {
		uint8_t *buffer;
		int requested;
		xsUnsignedValue byteLength;
		uint8_t allocate = 1;
		
		if (0 == xsmcArgc)
			requested = available;
		else if (xsReferenceType == xsmcTypeOf(xsArg(0))) {
			xsResult = xsArg(0);
			xsmcGetBufferWritable(xsResult, (void **)&buffer, &byteLength);
			requested = (int)byteLength;
			allocate = 0;
		}
		else
			requested = xsmcToInteger(xsArg(0));

		if ((requested <= 0) || (requested > available)) 
			xsUnknownError("invalid");

		if (allocate)
			buffer = xsmcSetArrayBuffer(xsResult, NULL, requested);

		while (requested--) {
			if (0 != fifo_get(&serial->rx_fifo, buffer++))
				xsUnknownError("no data");
		}
	}

	serial->rxInterruptEnabled = (NULL != serial->onReadable);
	uart_irq();
}

void xs_serial_write(xsMachine *the)
{