//*****************************************************************************
// startup_gcc.c
//
// Startup code for use with GCC.
//
// Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com/ 
// 
// 
//  Redistribution and use in source and binary forms, with or without 
//  modification, are permitted provided that the following conditions 
//  are met:
//
//    Redistributions of source code must retain the above copyright 
//    notice, this list of conditions and the following disclaimer.
//
//    Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the 
//    documentation and/or other materials provided with the   
//    distribution.
//
//    Neither the name of Texas Instruments Incorporated nor the names of
//    its contributors may be used to endorse or promote products derived
//    from this software without specific prior written permission.
//
//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
//  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
//  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
//  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
//  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
//  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
//  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
//  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
//  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
//  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
//  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//*****************************************************************************

#include <stdint.h>
#include "hw_nvic.h"
#include "hw_types.h"

//*****************************************************************************
//
// Heap block pointers defined by linker script
//
//*****************************************************************************
static char *heap_end = 0;
extern unsigned long _heap;
extern unsigned long _eheap;

//*****************************************************************************
//
// Forward declaration of the default fault handlers.
//
//*****************************************************************************
void ResetISR(void);
static void NmiSR(void);
static void FaultISR(void);
static void IntDefaultHandler(void);
static void BusFaultHandler(void);

//*****************************************************************************
//
// External declaration for the reset handler that is to be called when the
// processor is started
//
//*****************************************************************************
extern void _c_int00(void);
extern void vPortSVCHandler(void);
extern void xPortPendSVHandler(void);
extern void xPortSysTickHandler(void);

//*****************************************************************************
//
// The entry point for the application.
//
//*****************************************************************************
extern int main(void);

//*****************************************************************************
//
// Reserve space for the system stack.
//
//*****************************************************************************
static uint32_t pui32Stack[1024];

//*****************************************************************************
//
// The vector table.  Note that the proper constructs must be placed on this to
// ensure that it ends up at physical address 0x0000.0000.
//
//*****************************************************************************
__attribute__ ((section(".intvecs")))
void (* const g_pfnVectors[256])(void) =
{
    (void (*)(void))((uint32_t)pui32Stack + sizeof(pui32Stack)),
                                            // The initial stack pointer
    ResetISR,                               // The reset handler
    NmiSR,                                  // The NMI handler
    FaultISR,                               // The hard fault handler
    IntDefaultHandler,                      // The MPU fault handler
    BusFaultHandler,                        // The bus fault handler
    IntDefaultHandler,                      // The usage fault handler
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
#ifdef USE_FREERTOS
    vPortSVCHandler,                        // SVCall handler
#else
    IntDefaultHandler,                      // SVCall handler
#endif
    IntDefaultHandler,                      // Debug monitor handler
    0,                                      // Reserved
#ifdef USE_FREERTOS
    xPortPendSVHandler,                     // The PendSV handler
    xPortSysTickHandler,                    // The SysTick handler
#else
    IntDefaultHandler,                      // The PendSV handler
    IntDefaultHandler,                      // The SysTick handler
#endif
    IntDefaultHandler,                      // GPIO Port A0
    IntDefaultHandler,                      // GPIO Port A1
    IntDefaultHandler,                      // GPIO Port A2
    IntDefaultHandler,                      // GPIO Port A3
    0,                                      // Reserved
    IntDefaultHandler,                      // UART0 Rx and Tx
    IntDefaultHandler,                      // UART1 Rx and Tx
    0,                                      // Reserved
    IntDefaultHandler,                      // I2C0 Master and Slave
    0,0,0,0,0,                              // Reserved
    IntDefaultHandler,                      // ADC Channel 0
    IntDefaultHandler,                      // ADC Channel 1
    IntDefaultHandler,                      // ADC Channel 2
    IntDefaultHandler,                      // ADC Channel 3
    IntDefaultHandler,                      // Watchdog Timer
    IntDefaultHandler,                      // Timer 0 subtimer A                      
    IntDefaultHandler,                      // Timer 0 subtimer B
    IntDefaultHandler,                      // Timer 1 subtimer A
    IntDefaultHandler,                      // Timer 1 subtimer B
    IntDefaultHandler,                      // Timer 2 subtimer A
    IntDefaultHandler,                      // Timer 2 subtimer B 
    0,0,0,0,                                // Reserved
    IntDefaultHandler,                      // Flash
    0,0,0,0,0,                              // Reserved
    IntDefaultHandler,                      // Timer 3 subtimer A
    IntDefaultHandler,                      // Timer 3 subtimer B
    0,0,0,0,0,0,0,0,0,                      // Reserved
    IntDefaultHandler,                      // uDMA Software Transfer
    IntDefaultHandler,                      // uDMA Error
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    IntDefaultHandler,                      // SHA
    0,0,                                    // Reserved
    IntDefaultHandler,                      // AES
    0,                                      // Reserved
    IntDefaultHandler,                      // DES
    0,0,0,0,0,                              // Reserved
    IntDefaultHandler,                      // SDHost
    0,                                      // Reserved
    IntDefaultHandler,                      // I2S
    0,                                      // Reserved
    IntDefaultHandler,                      // Camera
    0,0,0,0,0,0,0,                          // Reserved
    IntDefaultHandler,                      // NWP to APPS Interrupt
    IntDefaultHandler,                      // Power, Reset and Clock module
    0,0,                                    // Reserved
    IntDefaultHandler,                      // Shared SPI
    IntDefaultHandler,                      // Generic SPI
    IntDefaultHandler,                      // Link SPI
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0,0,0,0,0,0,0,0,0,                    // Reserved
    0,0                                     // Reserved
};

//*****************************************************************************
//
// The following are constructs created by the linker, indicating where the
// the "data" and "bss" segments reside in memory.  The initializers for the
// for the "data" segment resides immediately following the "text" segment.
//
//*****************************************************************************
extern uint32_t _etext;
extern uint32_t _data;
extern uint32_t _edata;
extern uint32_t _bss;
extern uint32_t _ebss;
extern uint32_t __init_data;

//*****************************************************************************
//
// This is the code that gets called when the processor first starts execution
// following a reset event.  Only the absolutely necessary set is performed,
// after which the application supplied entry() routine is called.  Any fancy
// actions (such as making decisions based on the reset cause register, and
// resetting the bits in that register) are left solely in the hands of the
// application.
//
//*****************************************************************************
void
ResetISR(void)
{
    uint32_t *pui32Src, *pui32Dest;

    //
    // Copy the data segment initializers
    //
    pui32Src = &__init_data;
    for(pui32Dest = &_data; pui32Dest < &_edata; )
    {
        *pui32Dest++ = *pui32Src++;
    }

    //
    // Zero fill the bss segment.
    //
    __asm("    ldr     r0, =_bss\n"
          "    ldr     r1, =_ebss\n"
          "    mov     r2, #0\n"
          "    .thumb_func\n"
          "zero_loop:\n"
          "        cmp     r0, r1\n"
          "        it      lt\n"
          "        strlt   r2, [r0], #4\n"
          "        blt     zero_loop");

    //
    // Call the application's entry point.
    //
    main();
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a NMI.  This
// simply enters an infinite loop, preserving the system state for examination
// by a debugger.
//
//*****************************************************************************
static void
NmiSR(void)
{
    //
    // Enter an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a fault
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
FaultISR(void)
{
    //
    // Enter an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives an unexpected
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************

static void
BusFaultHandler(void)
{
    //
    // Go into an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives an unexpected
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
IntDefaultHandler(void)
{
    //
    // Go into an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This function is used by dynamic memory allocation API(s) in newlib 
// library
//
//*****************************************************************************
void * _sbrk(unsigned int incr)
{

    char *prev_heap_end;

    //
    // Check if this function is calld for the
    // first time and the heap end pointer
    //
    if (heap_end == 0)
    {
        heap_end = (char *)&_heap; 
    }

    //
    // Check if we have enough heap memory available
    //
    prev_heap_end = heap_end;
    if (heap_end + incr > (char *)&_eheap)
    {
    //
    // Return error
    //
        return 0;
    }

    //
    // Set the new heap end pointer
    //
    heap_end += incr;
    
    //
    // Return the pointer to the newly allocated memory
    //
    return prev_heap_end;

}