/**
 * Copyright (c) 2011-2025 Bill Greiman
 * This file is part of the SdFat library for SD memory cards.
 *
 * MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
#define FREE_STACK_CPP
#include "FreeStack.h"
#if defined(HAS_UNUSED_STACK) && HAS_UNUSED_STACK
//------------------------------------------------------------------------------
inline char *stackBegin()
{
#if defined(__AVR__)
    return __brkval ? __brkval : &__bss_end;
#elif defined(__IMXRT1062__)
    return reinterpret_cast<char *>(&_ebss);
#elif defined(__arm__)
    return reinterpret_cast<char *>(sbrk(0));
#else // defined(__AVR__)
#error "undefined stackBegin"
#endif // defined(__AVR__)
}
//------------------------------------------------------------------------------
inline char *stackPointer()
{
#if defined(__AVR__)
    return reinterpret_cast<char *>(SP);
#elif defined(__arm__)
    register uint32_t sp asm("sp");
    return reinterpret_cast<char *>(sp);
#else // defined(__AVR__)
#error "undefined stackPointer"
#endif // defined(__AVR__)
}
//------------------------------------------------------------------------------
/** Stack fill pattern. */
const char FILL = 0x55;
void FillStack()
{
    char *p = stackBegin();
    const char *top = stackPointer();
    while (p < top)
    {
        *p++ = FILL;
    }
}
//------------------------------------------------------------------------------
// May fail if malloc or new is used.
int UnusedStack()
{
    char *h = stackBegin();
    const char *top = stackPointer();
    int n;

    for (n = 0; (h + n) < top; n++)
    {
        if (h[n] != FILL)
        {
            if (n >= 16)
            {
                break;
            }
            // Attempt to skip used heap.
            h += n;
            n = 0;
        }
    }
    return n;
}
#endif // defined(HAS_UNUSED_STACK) && HAS_UNUSED_STACK
