contrib/loaders/flash/msp432/startup_msp432e4.c

   1 // SPDX-License-Identifier: BSD-3-Clause
   2
   3 /******************************************************************************
   4 *
   5 * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/
   6 *
   7 ******************************************************************************/
   8
   9 #include <stdint.h>
  10
  11 /* Entry point for the application. */
  12 extern int main();
  13
  14 /* Reserve space for the system stack. */
  15 extern uint32_t __stack_top;
  16
  17 typedef void(*pFunc)(void);
  18
  19 /* Interrupt handler prototypes */
  20 void default_handler(void);
  21 void reset_handler(void);
  22
  23 /*
  24  * The vector table.  Note that the proper constructs must be placed on this to
  25  * ensure that it ends up at physical address 0x0000.0000 or at the start of
  26  * the program if located at a start address other than 0.
  27  */
  28 void (* const intr_vectors[])(void) __attribute__((section(".intvecs"))) = {
  29         (pFunc)&__stack_top, /* The initial stack pointer */
  30         reset_handler,       /* The reset handler         */
  31         default_handler,     /* The NMI handler           */
  32         default_handler,     /* The hard fault handler    */
  33         default_handler,     /* The MPU fault handler     */
  34         default_handler,     /* The bus fault handler     */
  35         default_handler,     /* The usage fault handler   */
  36         0,                   /* Reserved                  */
  37         0,                   /* Reserved                  */
  38         0,                   /* Reserved                  */
  39         0,                   /* Reserved                  */
  40         default_handler,     /* SVCall handler            */
  41         default_handler,     /* Debug monitor handler     */
  42         0,                   /* Reserved                  */
  43         default_handler,     /* The PendSV handler        */
  44         default_handler      /* The SysTick handler       */
  45 };
  46
  47 /*
  48  * The following are constructs created by the linker, indicating where
  49  * the "data" and "bss" segments reside in memory.  The initializers for
  50  * the "data" segment resides immediately following the "text" segment.
  51  */
  52 extern uint32_t __bss_start__;
  53 extern uint32_t __bss_end__;
  54
  55 /*
  56  * This is the code that gets called when the processor first starts execution
  57  * following a reset event.  Only the absolutely necessary set is performed,
  58  * after which the application supplied entry() routine is called.  Any fancy
  59  * actions (such as making decisions based on the reset cause register, and
  60  * resetting the bits in that register) are left solely in the hands of the
  61  * application.
  62  */
  63 __attribute__((section(".reset"))) __attribute__((naked))
  64 void reset_handler(void)
  65 {
  66         /* Set stack pointer */
  67         __asm("    MOVW.W  r0, #0x1700\n"
  68                   "    MOVT.W  r0, #0x2000\n"
  69                   "    mov     sp, r0\n");
  70
  71         /* Zero fill the bss segment. */
  72         __asm("    ldr     r0, =__bss_start__\n"
  73                   "    ldr     r1, =__bss_end__\n"
  74                   "    mov     r2, #0\n"
  75                   "    .thumb_func\n"
  76                   "zero_loop:\n"
  77                   "    cmp     r0, r1\n"
  78                   "    it      lt\n"
  79                   "    strlt   r2, [r0], #4\n"
  80                   "    blt     zero_loop");
  81
  82         /* Call the application's entry point. */
  83         main();
  84 }
  85
  86 /*
  87  * This is the code that gets called when the processor receives an unexpected
  88  * interrupt.  This simply enters an infinite loop, preserving the system state
  89  * for examination by a debugger.
  90  */
  91 void default_handler(void)
  92 {
  93         /* Enter an infinite loop. */
  94         while (1)
  95                 ;
  96 }