text: /****************************************************************************
   * arch/arm/src/nuc1xx/nuc_start.c
   *
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.  The
   * ASF licenses this file to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance with the
   * License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations
   * under the License.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <stdint.h>
  #include <assert.h>
  #include <debug.h>
  
  #include <nuttx/init.h>
  
  #include "arm_arch.h"
  #include "arm_internal.h"
  
  #include "nuc_config.h"
  #include "nuc_lowputc.h"
  #include "nuc_clockconfig.h"
  #include "nuc_userspace.h"
  #include "nuc_start.h"
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  /* Memory Map:
   *
   * 0x0000:0000 - Beginning of FLASH. Address of exception vectors.
   * 0x0001:ffff - End of flash (assuming 128KB of FLASH)
   * 0x2000:0000 - Start of SRAM and start of .data (_sdata)
   *             - End of .data (_edata) abd start of .bss (_sbss)
   *             - End of .bss (_ebss) and bottom of idle stack
   *             - _ebss + CONFIG_IDLETHREAD_STACKSIZE = end of idle stack,
   *               start of heap
   * 0x2000:3fff - End of SRAM and end of heap (assuming 16KB of SRAM)
   */
  
  #define IDLE_STACK ((uint32_t)&_ebss+CONFIG_IDLETHREAD_STACKSIZE-4)
  #define HEAP_BASE  ((uint32_t)&_ebss+CONFIG_IDLETHREAD_STACKSIZE)
  
  /****************************************************************************
   * Public Data
   ****************************************************************************/
  
  const uintptr_t g_idle_topstack = IDLE_STACK;
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: showprogress
   *
   * Description:
   *   Print a character on the UART to show boot status.
   *
   ****************************************************************************/
  
  #if defined(CONFIG_DEBUG_FEATURES) && defined(HAVE_SERIAL_CONSOLE)
  #  define showprogress(c) nuc_lowputc((uint32_t)c)
  #else
  #  define showprogress(c)
  #endif
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: _start
   *
   * Description:
   *   This is the reset entry point.
   *
   ****************************************************************************/
  
  void __start(void)
  {
    const uint32_t *src;
    uint32_t *dest;
  
    /* Configure the uart so that we can get debug output as soon as possible */
  
    nuc_clockconfig();
    nuc_lowsetup();
    showprogress('A');
  
    /* Clear .bss.  We'll do this inline (vs. calling memset) just to be
     * certain that there are no issues with the state of global variables.
     */
  
    for (dest = &_sbss; dest < &_ebss; )
      {
        *dest++ = 0;
      }
  
    showprogress('B');
  
    /* Move the initialized data section from his temporary holding spot in
     * FLASH into the correct place in SRAM.  The correct place in SRAM is
     * give by _sdata and _edata.  The temporary location is in FLASH at the
     * end of all of the other read-only data (.text, .rodata) at _eronly.
     */
  
    for (src = &_eronly, dest = &_sdata; dest < &_edata; )
      {
        *dest++ = *src++;
      }
  
    showprogress('C');
  
    /* Perform early serial initialization */
  
  #ifdef USE_EARLYSERIALINIT
    arm_earlyserialinit();
  #endif
    showprogress('D');
  
    /* For the case of the separate user-/kernel-space build, perform whatever
     * platform specific initialization of the user memory is required.
     * Normally this just means initializing the user space .data and .bss
     * segments.
     */
  
  #ifdef CONFIG_BUILD_PROTECTED
    nuc_userspace();
    showprogress('E');
  #endif
  
    /* Initialize onboard resources */
  
    nuc_boardinitialize();
    showprogress('F');
  
    /* Then start NuttX */
  
    showprogress('\r');
    showprogress('\n');
    nx_start();
  
    /* Shouldn't get here */
  
    for (; ; );
  }
  