22. Realization of message processing task

\qquad Here is HD-GR GNSS Message processing task implementation code of navigation software ：

// main_message.c -- Navigation message processing task.

/* * Copyright (C) 2005 Andrew Greenberg * Distributed under the GNU GENERAL PUBLIC LICENSE (GPL) Version 2 (June 1991). * See the "COPYING" file distributed with this software for more information. */

/* Namuru GPS receiver project * Original : message.c * Mods : driving LED part has commented/replaced for Namuru HW * version : V1.1 * date : 8/7/2008 */

/* * HD-GR GNSS receiver project * Modes : Inherited the code of message.c in the Namuru GPS receiver project * V1.0 and made necessary adjustments to adapt to the new RTOS and * functions. * version : V1.0 * date : xx/xx/2015 */

#include <io.h>
#include <stdio.h>
#include <math.h>
#include "includes.h"
#include "system.h"
#include "altera_avalon_pio_regs.h"
#include "alt_types.h"
#include "sys/alt_irq.h"
#include "gps_message.h"
#include "b1i_message.h"
#include "main_ephemeris.h"
#include "main_position.h"

/****************************************************************************** * Defines ******************************************************************************/

/****************************************************************************** * Globals ******************************************************************************/

OS_FLAG_GRP *m_MessageFlag __attribute__ ((section(".isrdata.rwdata")));
OS_FLAGS channels_with_subframes __attribute__ ((section(".isrdata.rwdata")));

/****************************************************************************** * Statics ******************************************************************************/

/****************************************************************************** * Stuff incoming bits from the accum_task into words and subframes in * the messages structure. ******************************************************************************/
void message_task(void* pdata) // input 'pdata' not used
{
    
	INT8U err;
	OS_FLAGS channels_with_bits, channel_bits;

	// There's no way that we're going to get a bit before this thread
	// is first executed, so it's ok to run the flag init here.
	m_MessageFlag = OSFlagCreate((OS_FLAGS)0, &err);

	while (1) {
    
		// Block if there are no channels with bits ready. Wake up if any bits
		// from the 20 channels (0xFFFFF) are set. Clear the flag on wakeup,
		// with the bits saved in channels_with_bits.
		channels_with_bits = OSFlagPend(m_MessageFlag,
			(1 << TOT_MAX_CHANNELS) - 1,
			OS_FLAG_WAIT_SET_ANY + OS_FLAG_CONSUME, 
			0, &err);

		// OK we're awake, process the messages
		GNSS_ENTER_CRITICAL();
		channel_bits = g_channel_bits;
		GNSS_EXIT_CRITICAL();

		// led_turnon(LED3);

		// Clear the flag IPC shadow (see below)
		channels_with_subframes = 0;
		if (m_sys_posconst & POS_CONSTELL_BDS) {
    
			b1i_process_message(channels_with_bits >> GPS_MAX_CHANNELS, 
				channel_bits >> GPS_MAX_CHANNELS);
			channels_with_subframes <<= GPS_MAX_CHANNELS;
		}
		if (m_sys_posconst & POS_CONSTELL_GPS) {
    
			gps_process_message(channels_with_bits, channel_bits);
		}

        // Wake up the ephemeris thread if there are subframes ready
        if (channels_with_subframes) {
    
			OSFlagPost(m_EphemerisChannelFlag, channels_with_subframes, OS_FLAG_SET, &err);
		}
        
		// led_turnoff(LED3);
    }
}