Method CommReceive

source/SerialComms.cpp:654–709

//===========================================================================

BYTE __stdcall CSuperSerialCard::CommReceive(WORD, WORD, BYTE, BYTE, ULONG)
{
	if (!CheckComm())
		return 0;

	BYTE result = 0;

	if (!m_qTcpSerialBuffer.empty())
	{
		// NB. See CommTcpSerialReceive() above, for a note explaining why there's no need for a critical section here

		// If receiver is disabled then transmitting device should not send data
		// . For COM serial connection this is handled by DTR/DTS flow-control (which enables the receiver)
		if ((m_uCommandByte & CMD_DTR) == 0)	// Receiver disable, so prevent receiving data
			return 0;

		result = m_qTcpSerialBuffer.front();
		m_qTcpSerialBuffer.pop_front();

		if (m_bRxIrqEnabled && !m_qTcpSerialBuffer.empty())
		{
			CpuIrqAssert(IS_SSC);
			m_vbRxIrqPending = true;
		}
	}
	else if (m_hCommHandle != INVALID_HANDLE_VALUE)
	{
		EnterCriticalSection(&m_CriticalSection);
		{
			const UINT uCOMIdx = m_vuRxCurrBuffer;
			const UINT uSSCIdx = uCOMIdx ^ 1;
			if (!m_qComSerialBuffer[uSSCIdx].empty())
			{
				result = m_qComSerialBuffer[uSSCIdx].front();
				m_qComSerialBuffer[uSSCIdx].pop_front();

				UINT uNewSSCIdx = uSSCIdx;
				if ( m_qComSerialBuffer[uSSCIdx].empty() &&		// Current SSC buffer is empty
					!m_qComSerialBuffer[uCOMIdx].empty() )		// Current COM buffer has data
				{
					m_vuRxCurrBuffer = uSSCIdx;				// Flip buffers
					uNewSSCIdx = uCOMIdx;
				}

				if (m_bRxIrqEnabled && !m_qComSerialBuffer[uNewSSCIdx].empty())
				{
					CpuIrqAssert(IS_SSC);
					m_vbRxIrqPending = true;
				}
			}
		}
		LeaveCriticalSection(&m_CriticalSection);
	}

	return result;
}

//===========================================================================