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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Source/] [portable/] [GCC/] [NiosII/] [port.c] - Blame information for rev 572

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1 572 jeremybenn
/*
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    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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    ***************************************************************************
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    *                                                                         *
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    * If you are:                                                             *
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    *                                                                         *
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    *    + New to FreeRTOS,                                                   *
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    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
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    *    + Looking for basic training,                                        *
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    *    + Wanting to improve your FreeRTOS skills and productivity           *
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    *                                                                         *
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    * then take a look at the FreeRTOS books - available as PDF or paperback  *
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    *                                                                         *
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    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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    *                  http://www.FreeRTOS.org/Documentation                  *
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    *                                                                         *
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    * A pdf reference manual is also available.  Both are usually delivered   *
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    * to your inbox within 20 minutes to two hours when purchased between 8am *
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    * and 8pm GMT (although please allow up to 24 hours in case of            *
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    * exceptional circumstances).  Thank you for your support!                *
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    *                                                                         *
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    ***************************************************************************
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    This file is part of the FreeRTOS distribution.
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    FreeRTOS is free software; you can redistribute it and/or modify it under
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    the terms of the GNU General Public License (version 2) as published by the
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    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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    ***NOTE*** The exception to the GPL is included to allow you to distribute
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    a combined work that includes FreeRTOS without being obliged to provide the
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    source code for proprietary components outside of the FreeRTOS kernel.
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    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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    more details. You should have received a copy of the GNU General Public
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    License and the FreeRTOS license exception along with FreeRTOS; if not it
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    can be viewed here: http://www.freertos.org/a00114.html and also obtained
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    by writing to Richard Barry, contact details for whom are available on the
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    FreeRTOS WEB site.
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    1 tab == 4 spaces!
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    http://www.FreeRTOS.org - Documentation, latest information, license and
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    contact details.
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    http://www.SafeRTOS.com - A version that is certified for use in safety
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    critical systems.
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    http://www.OpenRTOS.com - Commercial support, development, porting,
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    licensing and training services.
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*/
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/*-----------------------------------------------------------
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 * Implementation of functions defined in portable.h for the NIOS2 port.
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 *----------------------------------------------------------*/
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/* Standard Includes. */
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#include <string.h>
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#include <errno.h>
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/* Altera includes. */
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#include "sys/alt_irq.h"
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#include "altera_avalon_timer_regs.h"
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#include "priv/alt_irq_table.h"
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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/* Interrupts are enabled. */
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#define portINITIAL_ESTATUS     ( portSTACK_TYPE ) 0x01 
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/*-----------------------------------------------------------*/
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/*
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 * Setup the timer to generate the tick interrupts.
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 */
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static void prvSetupTimerInterrupt( void );
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/*
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 * Call back for the alarm function.
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 */
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void vPortSysTickHandler( void * context, alt_u32 id );
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/*-----------------------------------------------------------*/
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void prvReadGp( unsigned long *ulValue )
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{
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        asm( "stw gp, (r4) " );
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};
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/*-----------------------------------------------------------*/
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/*
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 * See header file for description.
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 */
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portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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{
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portSTACK_TYPE *pxFramePointer = pxTopOfStack - 1;
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portSTACK_TYPE xGlobalPointer;
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    prvReadGp( &xGlobalPointer );
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    /* End of stack marker. */
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    *pxTopOfStack = 0xdeadbeef;
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    pxTopOfStack--;
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    *pxTopOfStack = ( portSTACK_TYPE ) pxFramePointer;
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    pxTopOfStack--;
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    *pxTopOfStack = xGlobalPointer;
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    /* Space for R23 to R16. */
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    pxTopOfStack -= 9;
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    *pxTopOfStack = ( portSTACK_TYPE ) pxCode;
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    pxTopOfStack--;
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    *pxTopOfStack = portINITIAL_ESTATUS;
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    /* Space for R15 to R5. */
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    pxTopOfStack -= 12;
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    *pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
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    /* Space for R3 to R1, muldiv and RA. */
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    pxTopOfStack -= 5;
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    return pxTopOfStack;
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}
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/*-----------------------------------------------------------*/
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/*
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 * See header file for description.
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 */
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portBASE_TYPE xPortStartScheduler( void )
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{
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        /* Start the timer that generates the tick ISR.  Interrupts are disabled
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        here already. */
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        prvSetupTimerInterrupt();
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        /* Start the first task. */
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    asm volatile (  " movia r2, restore_sp_from_pxCurrentTCB        \n"
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                    " jmp r2                                          " );
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        /* Should not get here! */
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        return 0;
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler( void )
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{
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        /* It is unlikely that the NIOS2 port will require this function as there
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        is nothing to return to.  */
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}
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/*-----------------------------------------------------------*/
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/*
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 * Setup the systick timer to generate the tick interrupts at the required
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 * frequency.
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 */
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void prvSetupTimerInterrupt( void )
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{
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        /* Try to register the interrupt handler. */
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        if ( -EINVAL == alt_irq_register( SYS_CLK_IRQ, 0x0, vPortSysTickHandler ) )
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        {
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                /* Failed to install the Interrupt Handler. */
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                asm( "break" );
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        }
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        else
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        {
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                /* Configure SysTick to interrupt at the requested rate. */
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                IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_STOP_MSK );
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                IOWR_ALTERA_AVALON_TIMER_PERIODL( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) & 0xFFFF );
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                IOWR_ALTERA_AVALON_TIMER_PERIODH( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) >> 16 );
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                IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_CONT_MSK | ALTERA_AVALON_TIMER_CONTROL_START_MSK | ALTERA_AVALON_TIMER_CONTROL_ITO_MSK );
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        }
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        /* Clear any already pending interrupts generated by the Timer. */
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        IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
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}
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/*-----------------------------------------------------------*/
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void vPortSysTickHandler( void * context, alt_u32 id )
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{
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        /* Increment the Kernel Tick. */
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        vTaskIncrementTick();
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        /* If using preemption, also force a context switch. */
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        #if configUSE_PREEMPTION == 1
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        vTaskSwitchContext();
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        #endif
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        /* Clear the interrupt. */
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        IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK );
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}
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/*-----------------------------------------------------------*/
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/** This function is a re-implementation of the Altera provided function.
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 * The function is re-implemented to prevent it from enabling an interrupt
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 * when it is registered. Interrupts should only be enabled after the FreeRTOS.org
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 * kernel has its scheduler started so that contexts are saved and switched
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 * correctly.
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 */
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int alt_irq_register( alt_u32 id, void* context, void (*handler)(void*, alt_u32) )
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{
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        int rc = -EINVAL;
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        alt_irq_context status;
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        if (id < ALT_NIRQ)
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        {
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                /*
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                 * interrupts are disabled while the handler tables are updated to ensure
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                 * that an interrupt doesn't occur while the tables are in an inconsistent
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                 * state.
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                 */
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                status = alt_irq_disable_all ();
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                alt_irq[id].handler = handler;
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                alt_irq[id].context = context;
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                rc = (handler) ? alt_irq_enable (id): alt_irq_disable (id);
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                /* alt_irq_enable_all(status); This line is removed to prevent the interrupt from being immediately enabled. */
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        }
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        return rc;
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}
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/*-----------------------------------------------------------*/
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