startup.c

/*
 * Copyright (c) 2013 - 2014, Freescale Semiconductor, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * o Redistributions of source code must retain the above copyright notice, this list
 *   of conditions and the following disclaimer.
 *
 * o Redistributions in binary form must reproduce the above copyright notice, this
 *   list of conditions and the following disclaimer in the documentation and/or
 *   other materials provided with the distribution.
 *
 * o Neither the name of Freescale Semiconductor, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "startup.h"
#include "derivative.h"

#if (defined(__ICCARM__))
    #pragma section = ".data"
    #pragma section = ".data_init"
    #pragma section = ".bss"
#endif

/*******************************************************************************
 * Code
 ******************************************************************************/

/*FUNCTION**********************************************************************
 *
 * Function Name : init_data_bss
 * Description   : Make necessary initializations for RAM.
 * - Copy initialized data from ROM to RAM.
 * - Clear the zero-initialized data section.
 * - Copy the vector table from ROM to RAM. This could be an option.  
 *
 * Tool Chians:
 *   __GNUC__   : GCC
 *   __CC_ARM   : KEIL
 *   __ICCARM__ : IAR
 *
 *END**************************************************************************/
void init_data_bss(void)
{
    uint32_t n; 
    
    /* Addresses for VECTOR_TABLE and VECTOR_RAM come from the linker file */
#if defined(__CC_ARM)
    extern uint32_t Image$$VECTOR_ROM$$Base[];
    extern uint32_t Image$$VECTOR_RAM$$Base[];
    extern uint32_t Image$$RW_m_data$$Base[];

    #define __VECTOR_TABLE Image$$VECTOR_ROM$$Base  
    #define __VECTOR_RAM Image$$VECTOR_RAM$$Base  
    #define __RAM_VECTOR_TABLE_SIZE (((uint32_t)Image$$RW_m_data$$Base - (uint32_t)Image$$VECTOR_RAM$$Base))
#elif defined(__ICCARM__)
    extern uint32_t __RAM_VECTOR_TABLE_SIZE[];
    extern uint32_t __VECTOR_TABLE[];  
    extern uint32_t __VECTOR_RAM[];  
#elif defined(__GNUC__)
    extern uint32_t __VECTOR_TABLE[];
    extern uint32_t __VECTOR_RAM[];
    extern uint32_t __RAM_VECTOR_TABLE_SIZE_BYTES[];
    uint32_t __RAM_VECTOR_TABLE_SIZE = (uint32_t)(__RAM_VECTOR_TABLE_SIZE_BYTES);
#endif

    if (__VECTOR_RAM != __VECTOR_TABLE)
    {   
        /* Copy the vector table from ROM to RAM */
        for (n = 0; n < ((uint32_t)__RAM_VECTOR_TABLE_SIZE)/sizeof(uint32_t); n++)
        {
            __VECTOR_RAM[n] = __VECTOR_TABLE[n];
        }
        /* Point the VTOR to the position of vector table */
        SCB->VTOR = (uint32_t)__VECTOR_RAM;
    }
    else
    {
        /* Point the VTOR to the position of vector table */
        SCB->VTOR = (uint32_t)__VECTOR_TABLE;
    }

#if !defined(__CC_ARM) && !defined(__ICCARM__)
    
    /* Declare pointers for various data sections. These pointers
     * are initialized using values pulled in from the linker file */
    uint8_t * data_ram, * data_rom, * data_rom_end;
    uint8_t * bss_start, * bss_end;

    /* Get the addresses for the .data section (initialized data section) */
#if defined(__GNUC__)
    extern uint32_t __DATA_ROM[];
    extern uint32_t __DATA_RAM[];
    extern char __DATA_END[];
    data_ram = (uint8_t *)__DATA_RAM;
    data_rom = (uint8_t *)__DATA_ROM;
    data_rom_end  = (uint8_t *)__DATA_END;
    n = data_rom_end - data_rom;
#endif

    /* Copy initialized data from ROM to RAM */
    while (n--)
    {
        *data_ram++ = *data_rom++;
    }   
    
    /* Get the addresses for the .bss section (zero-initialized data) */
#if defined(__GNUC__)
    extern char __START_BSS[];
    extern char __END_BSS[];
    bss_start = (uint8_t *)__START_BSS;
    bss_end = (uint8_t *)__END_BSS;
#endif
                
    /* Clear the zero-initialized data section */
    n = bss_end - bss_start;
    while(n--)
    {
        *bss_start++ = 0;
    }
#endif /* !__CC_ARM && !__ICCARM__*/
}

/*******************************************************************************
 * EOF
 ******************************************************************************/