contrib/loaders/flash/msp432/startup_msp432e4.c

   1 /******************************************************************************
   2 *
   3 * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/
   4 *
   5 * Redistribution and use in source and binary forms, with or without
   6 * modification, are permitted provided that the following conditions
   7 * are met:
   8 *
   9 *  Redistributions of source code must retain the above copyright
  10 *  notice, this list of conditions and the following disclaimer.
  11 *
  12 *  Redistributions in binary form must reproduce the above copyright
  13 *  notice, this list of conditions and the following disclaimer in the
  14 *  documentation and/or other materials provided with the
  15 *  distribution.
  16 *
  17 *  Neither the name of Texas Instruments Incorporated nor the names of
  18 *  its contributors may be used to endorse or promote products derived
  19 *  from this software without specific prior written permission.
  20 *
  21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32 *
  33 ******************************************************************************/
  34
  35 #include <stdint.h>
  36
  37 /* Entry point for the application. */
  38 extern int main();
  39
  40 /* Reserve space for the system stack. */
  41 extern uint32_t __stack_top;
  42
  43 typedef void(*pFunc)(void);
  44
  45 /* Interrupt handler prototypes */
  46 void default_handler(void);
  47 void reset_handler(void);
  48
  49 /*
  50  * The vector table.  Note that the proper constructs must be placed on this to
  51  * ensure that it ends up at physical address 0x0000.0000 or at the start of
  52  * the program if located at a start address other than 0.
  53  */
  54 void (* const intr_vectors[])(void) __attribute__((section(".intvecs"))) = {
  55         (pFunc)&__stack_top, /* The initial stack pointer */
  56         reset_handler,       /* The reset handler         */
  57         default_handler,     /* The NMI handler           */
  58         default_handler,     /* The hard fault handler    */
  59         default_handler,     /* The MPU fault handler     */
  60         default_handler,     /* The bus fault handler     */
  61         default_handler,     /* The usage fault handler   */
  62         0,                   /* Reserved                  */
  63         0,                   /* Reserved                  */
  64         0,                   /* Reserved                  */
  65         0,                   /* Reserved                  */
  66         default_handler,     /* SVCall handler            */
  67         default_handler,     /* Debug monitor handler     */
  68         0,                   /* Reserved                  */
  69         default_handler,     /* The PendSV handler        */
  70         default_handler      /* The SysTick handler       */
  71 };
  72
  73 /*
  74  * The following are constructs created by the linker, indicating where the
  75  * the "data" and "bss" segments reside in memory.  The initializers for the
  76  * for the "data" segment resides immediately following the "text" segment.
  77  */
  78 extern uint32_t __bss_start__;
  79 extern uint32_t __bss_end__;
  80
  81 /*
  82  * This is the code that gets called when the processor first starts execution
  83  * following a reset event.  Only the absolutely necessary set is performed,
  84  * after which the application supplied entry() routine is called.  Any fancy
  85  * actions (such as making decisions based on the reset cause register, and
  86  * resetting the bits in that register) are left solely in the hands of the
  87  * application.
  88  */
  89 __attribute__((section(".reset"))) __attribute__((naked))
  90 void reset_handler(void)
  91 {
  92         /* Set stack pointer */
  93         __asm("    MOVW.W  r0, #0x1700\n"
  94                   "    MOVT.W  r0, #0x2000\n"
  95                   "    mov     sp, r0\n");
  96
  97         /* Zero fill the bss segment. */
  98         __asm("    ldr     r0, =__bss_start__\n"
  99                   "    ldr     r1, =__bss_end__\n"
 100                   "    mov     r2, #0\n"
 101                   "    .thumb_func\n"
 102                   "zero_loop:\n"
 103                   "    cmp     r0, r1\n"
 104                   "    it      lt\n"
 105                   "    strlt   r2, [r0], #4\n"
 106                   "    blt     zero_loop");
 107
 108         /* Call the application's entry point. */
 109         main();
 110 }
 111
 112 /*
 113  * This is the code that gets called when the processor receives an unexpected
 114  * interrupt.  This simply enters an infinite loop, preserving the system state
 115  * for examination by a debugger.
 116  */
 117 void default_handler(void)
 118 {
 119         /* Enter an infinite loop. */
 120         while (1)
 121                 ;
 122 }