/**
 * @file    heap.c
 * @brief   System level setup help
 */
 
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 * $Date: 2018-12-18 15:37:22 -0600 (Tue, 18 Dec 2018) $
 * $Revision: 40072 $
 *
 ******************************************************************************/
 
/* **** Includes **** */ 
#include <stdint.h>
#include <errno.h>
#include <unistd.h>

/**
 * @brief  sbrk
 * @detail Increase program data space
 * @detail Malloc and related functions depend on this
 */
 
/* **** declarations **** */
static char *heap_end = 0;
extern unsigned int __HeapBase;
extern unsigned int __HeapLimit;

/* **** functions **** */
caddr_t _sbrk(int incr)
{
    char *prev_heap_end;

    if (heap_end == 0) {
        heap_end = (caddr_t)&__HeapBase;
    }
    prev_heap_end = heap_end;

    if ((unsigned int)(heap_end + incr) > (unsigned int)&__HeapLimit) {
        errno = ENOMEM;
        return  (caddr_t) -1;
    }

    heap_end += incr;

    return (caddr_t) prev_heap_end;
}