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/*****************************************************************************
* SEGGER Microcontroller GmbH & Co. KG *
* Solutions for real time microcontroller applications *
*****************************************************************************
* *
* (c) 2017 SEGGER Microcontroller GmbH & Co. KG *
* *
* Internet: www.segger.com Support: [email protected] *
* *
*****************************************************************************/
/*****************************************************************************
* Preprocessor Definitions *
* ------------------------ *
* NO_FPU_ENABLE *
* *
* If defined, FPU will not be enabled. *
* *
* NO_STACK_INIT *
* *
* If defined, the stack pointer will not be initialised. *
* *
* NO_SYSTEM_INIT *
* *
* If defined, the SystemInit() function will not be called. By default *
* SystemInit() is called after reset to enable the clocks and memories to *
* be initialised prior to any C startup initialisation. *
* *
* NO_VTOR_CONFIG *
* *
* If defined, the vector table offset register will not be configured. *
* *
* MEMORY_INIT *
* *
* If defined, the MemoryInit() function will be called. By default *
* MemoryInit() is called after SystemInit() to enable an external memory *
* controller. *
* *
* STACK_INIT_VAL *
* *
* If defined, specifies the initial stack pointer value. If undefined, *
* the stack pointer will be initialised to point to the end of the *
* RAM segment. *
* *
* VECTORS_IN_RAM *
* *
* If defined, the exception vectors will be copied from Flash to RAM. *
* *
*****************************************************************************/
.syntax unified
.global Reset_Handler
.extern _vectors
.section .init, "ax"
.thumb_func
.equ VTOR_REG, 0xE000ED08
.equ FPU_CPACR_REG, 0xE000ED88
#ifndef STACK_INIT_VAL
#define STACK_INIT_VAL __RAM_segment_end__
#endif
Reset_Handler:
#ifndef NO_STACK_INIT
/* Initialise main stack */
ldr r0, =STACK_INIT_VAL
ldr r1, =0x7
bics r0, r1
mov sp, r0
#endif
#ifndef NO_SYSTEM_INIT
/* Initialise system */
ldr r0, =SystemInit
blx r0
#endif
#ifdef MEMORY_INIT
ldr r0, =MemoryInit
blx r0
#endif
#ifdef VECTORS_IN_RAM
/* Copy exception vectors into RAM */
ldr r0, =__vectors_start__
ldr r1, =__vectors_end__
ldr r2, =__vectors_ram_start__
1:
cmp r0, r1
beq 2f
ldr r3, [r0]
str r3, [r2]
adds r0, r0, #4
adds r2, r2, #4
b 1b
2:
#endif
#ifndef NO_VTOR_CONFIG
/* Configure vector table offset register */
ldr r0, =VTOR_REG
#ifdef VECTORS_IN_RAM
ldr r1, =_vectors_ram
#else
ldr r1, =_vectors
#endif
str r1, [r0]
#endif
#if (defined(__ARM_ARCH_FPV4_SP_D16__) || defined(__ARM_ARCH_FPV5_D16__)) && !defined(NO_FPU_ENABLE)
/* Enable FPU */
ldr r0, =FPU_CPACR_REG
ldr r1, [r0]
orr r1, r1, #(0xF << 20)
str r1, [r0]
dsb
isb
#endif
/* Jump to program start */
b _start
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