source: trunk/libs/newlib/src/libgloss/or1k/sbrk.c @ 546

Last change on this file since 546 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 1.7 KB
Line 
1/* sbrk.c -- allocate space on heap on OpenRISC 1000.
2 *
3 * Copyright (c) 2014 Authors
4 *
5 * Contributor Stefan Wallentowitz <stefan.wallentowitz@tum.de>
6 *
7 * The authors hereby grant permission to use, copy, modify, distribute,
8 * and license this software and its documentation for any purpose, provided
9 * that existing copyright notices are retained in all copies and that this
10 * notice is included verbatim in any distributions. No written agreement,
11 * license, or royalty fee is required for any of the authorized uses.
12 * Modifications to this software may be copyrighted by their authors
13 * and need not follow the licensing terms described here, provided that
14 * the new terms are clearly indicated on the first page of each file where
15 * they apply.
16 */
17
18#include <reent.h>
19
20#include "include/or1k-support.h"
21
22extern uint32_t end; /* Set by linker.  */
23uint32_t _or1k_heap_start = &end;
24uint32_t _or1k_heap_end;
25
26void *
27_sbrk_r (struct _reent * reent, ptrdiff_t incr)
28{
29        uint32_t        prev_heap_end;
30
31        // This needs to be atomic
32
33        // Disable interrupts on this core
34        uint32_t sr_iee = or1k_interrupts_disable();
35        uint32_t sr_tee = or1k_timer_disable();
36
37        // Initialize heap end to end if not initialized before
38        or1k_sync_cas((void*) &_or1k_heap_end, 0, (uint32_t) _or1k_heap_start);
39
40        do {
41                // Read previous heap end
42                prev_heap_end = _or1k_heap_end;
43                // and try to set it to the new value as long as it has changed
44        } while (or1k_sync_cas((void*) &_or1k_heap_end,
45                        (uint32_t) prev_heap_end,
46                        (uint32_t) (prev_heap_end + incr)) != (uint32_t) prev_heap_end);
47
48        // Restore interrupts on this core
49        or1k_timer_restore(sr_tee);
50        or1k_interrupts_restore(sr_iee);
51
52        return (void*) prev_heap_end;
53}
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