KDP_STATUS NTAPI KdpReceivePacketLeader ( OUT PULONG PacketLeader )
Definition at line 75 of file kdserial.c.
{
    UCHAR Index = 0, Byte, Buffer[4];
    KDP_STATUS KdStatus;

    /* Set first character to 0 */
    Buffer[0] = 0;

    do
    {
        /* Receive a single byte */
        KdStatus = KdpReceiveByte(&Byte);

        /* Check for timeout */
        if (KdStatus == KDP_PACKET_TIMEOUT)
        {
            /* Check if we already got a breakin byte */
            if (Buffer[0] == BREAKIN_PACKET_BYTE)
            {
                return KDP_PACKET_RESEND;
            }

            /* Report timeout */
            return KDP_PACKET_TIMEOUT;
        }

        /* Check if we received a byte */
        if (KdStatus == KDP_PACKET_RECEIVED)
        {
            /* Check if this is a valid packet leader byte */
            if (Byte == PACKET_LEADER_BYTE ||
                Byte == CONTROL_PACKET_LEADER_BYTE)
            {
                /* Check if we match the first byte */
                if (Byte != Buffer[0])
                {
                    /* No, this is the new byte 0! */
                    Index = 0;
                }

                /* Store the byte in the buffer */
                Buffer[Index] = Byte;

                /* Continue with next byte */
                Index++;
                continue;
            }

            /* Check for breakin byte */
            if (Byte == BREAKIN_PACKET_BYTE)
            {
                KDDBGPRINT("BREAKIN_PACKET_BYTE\n");
                Index = 0;
                Buffer[0] = Byte;
                continue;
            }
        }

        /* Restart */
        Index = 0;
        Buffer[0] = 0;
    }
    while (Index < 4);

    /* Enable the debugger */
    KdDebuggerNotPresent = FALSE;
    SharedUserData->KdDebuggerEnabled |= 0x00000002;

    /* Return the received packet leader */
    *PacketLeader = *(PULONG)Buffer;

    return KDP_PACKET_RECEIVED;
}
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