94 lines
4.0 KiB
C
94 lines
4.0 KiB
C
/****************************************************************************************
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| Description: Demo program C startup source file
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| File Name: cstart.c
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|----------------------------------------------------------------------------------------
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| C O P Y R I G H T
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|----------------------------------------------------------------------------------------
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| Copyright (c) 2011 by Feaser http://www.feaser.com All rights reserved
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|----------------------------------------------------------------------------------------
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| L I C E N S E
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|----------------------------------------------------------------------------------------
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| This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
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| modify it under the terms of the GNU General Public License as published by the Free
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| Software Foundation, either version 3 of the License, or (at your option) any later
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| version.
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| OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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| without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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| PURPOSE. See the GNU General Public License for more details.
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| You should have received a copy of the GNU General Public License along with OpenBLT.
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| If not, see <http://www.gnu.org/licenses/>.
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| A special exception to the GPL is included to allow you to distribute a combined work
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| that includes OpenBLT without being obliged to provide the source code for any
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| proprietary components. The exception text is included at the bottom of the license
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| file <license.html>.
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****************************************************************************************/
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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include "header.h" /* generic header */
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/****************************************************************************************
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* External function protoypes
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****************************************************************************************/
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extern int main(void);
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/****************************************************************************************
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* External data declarations
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****************************************************************************************/
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/* these externals are declared by the linker */
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extern unsigned long _etext;
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extern unsigned long _data;
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extern unsigned long _edata;
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extern unsigned long _bss;
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extern unsigned long _ebss;
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extern unsigned long _estack;
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/****************************************************************************************
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** NAME: reset_handler
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: Reset interrupt service routine. Configures the stack, initializes
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** RAM and jumps to function main.
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**
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****************************************************************************************/
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void reset_handler(void)
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{
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unsigned long *pSrc, *pDest;
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/* initialize stack pointer */
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__asm(" ldr r1, =_estack\n"
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" mov sp, r1");
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/* copy the data segment initializers from flash to SRAM */
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pSrc = &_etext;
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for(pDest = &_data; pDest < &_edata; )
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{
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*pDest++ = *pSrc++;
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}
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/* zero fill the bss segment. this is done with inline assembly since this will
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* clear the value of pDest if it is not kept in a register.
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*/
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__asm(" ldr r0, =_bss\n"
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" ldr r1, =_ebss\n"
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" mov r2, #0\n"
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" .thumb_func\n"
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"zero_loop:\n"
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" cmp r0, r1\n"
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" it lt\n"
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" strlt r2, [r0], #4\n"
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" blt zero_loop");
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/* start the software application by calling its entry point */
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main();
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} /*** end of reset_handler ***/
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/************************************ end of cstart.c **********************************/ |