1 /*
2  * Copyright (c) 2015, Freescale Semiconductor, Inc.
3  * Copyright 2016-2019, 2022, 2024 NXP
4  * All rights reserved.
5  *
6  * SPDX-License-Identifier: BSD-3-Clause
7  */
8 #if defined(__GNUC__)
9 #include <errno.h>
10 #include <stdint.h>
11 #include <stddef.h>
12 #endif
13 
14 #if defined(__GNUC__)
15 /*!
16  * @brief Function to override ARMGCC default function _sbrk
17  *
18  * _sbrk is called by malloc. ARMGCC default _sbrk compares "SP" register and
19  * heap end, if heap end is larger than "SP", then _sbrk returns error and
20  * memory allocation failed. This function changes to compare __HeapLimit with
21  * heap end.
22  */
23 void * _sbrk(ptrdiff_t incr);
_sbrk(ptrdiff_t incr)24 void * _sbrk(ptrdiff_t incr)
25 {
26     extern char end __asm("end");
27     extern char heap_limit __asm("__HeapLimit");
28     static char *heap_end;
29     char *prev_heap_end;
30     void *ret;
31 
32     if (heap_end == NULL)
33     {
34         heap_end = &end;
35     }
36 
37     prev_heap_end = heap_end;
38 
39     if ((uintptr_t)heap_end + (uintptr_t)incr > (uintptr_t)(&heap_limit))
40     {
41         errno = ENOMEM;
42 
43         ret = (void *)-1;
44     }
45     else
46     {
47         heap_end = (char *)((uintptr_t)heap_end + (uintptr_t)incr);
48 
49         ret = (void *)prev_heap_end;
50     }
51 
52     return ret;
53 }
54 #endif
55