79 lines
2.3 KiB
ArmAsm
79 lines
2.3 KiB
ArmAsm
/********************************************************************************
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* \file startup.s
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* \brief Startup file for Kinetis L (KL25Z).
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* This module performs:
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* - Set the initial SP
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* - Set the initial PC == __thumb_startup,
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* - Branches to main in the C library (which eventually
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* calls main()).
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******************************************************************************/
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.syntax unified
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.cpu cortex-m4
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.thumb
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.global g_pfnVectors
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.global Default_Handler
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/* start address for the initialization values of the .data section. defined in linker script */
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.word ___ROM_AT
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/* start address for the .data section. defined in linker script */
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.word _sdata
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/* end address for the .data section. defined in linker script */
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.word _edata
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/* start address for the .bss section. defined in linker script */
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.word __START_BSS
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/* end address for the .bss section. defined in linker script */
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.word __END_BSS
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/**
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* \brief This is the code that gets called when the processor first
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* starts execution following a reset event. Only the absolutely
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* necessary set is performed, after which the application
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* supplied main() routine is called.
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* \param None
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* \retval : None
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*/
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.section .text.__thumb_startup
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.weak __thumb_startup
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.type __thumb_startup, %function
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__thumb_startup:
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/* Call the C hardware init function (which also has to switch off the watchdog) */
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bl __init_hardware
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/* Copy the data segment initializers from flash to SRAM: */
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movs r1, #0
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b LoopCopyDataInit
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CopyDataInit:
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ldr r3, =___ROM_AT
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ldr r3, [r3, r1]
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str r3, [r0, r1]
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adds r1, r1, #4
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LoopCopyDataInit:
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ldr r0, =_sdata
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ldr r3, =_edata
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adds r2, r0, r1
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cmp r2, r3
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bcc CopyDataInit
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ldr r2, =__START_BSS
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b LoopFillZerobss
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/* Zero fill the bss segment: */
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FillZerobss:
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movs r3, #0
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str r3, [r2]
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adds r2, r2, #4
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LoopFillZerobss:
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ldr r3, = __END_BSS
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cmp r2, r3
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bcc FillZerobss
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/* Call the application's entry point: */
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bl main
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blx r0 /*Call the startup code of the application (address returned by the main() function of the boot loader)*/
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bx lr
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.size __thumb_startup, .-__thumb_startup
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/****END OF FILE****/
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