54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
/* sbrk.c -- allocate space on heap on OpenRISC 1000.
|
|
*
|
|
* Copyright (c) 2014 Authors
|
|
*
|
|
* Contributor Stefan Wallentowitz <stefan.wallentowitz@tum.de>
|
|
*
|
|
* The authors hereby grant permission to use, copy, modify, distribute,
|
|
* and license this software and its documentation for any purpose, provided
|
|
* that existing copyright notices are retained in all copies and that this
|
|
* notice is included verbatim in any distributions. No written agreement,
|
|
* license, or royalty fee is required for any of the authorized uses.
|
|
* Modifications to this software may be copyrighted by their authors
|
|
* and need not follow the licensing terms described here, provided that
|
|
* the new terms are clearly indicated on the first page of each file where
|
|
* they apply.
|
|
*/
|
|
|
|
#include <reent.h>
|
|
|
|
#include "include/or1k-support.h"
|
|
|
|
extern uint32_t end; /* Set by linker. */
|
|
uint32_t _or1k_heap_start = &end;
|
|
static uint32_t _or1k_heap_end;
|
|
|
|
void *
|
|
_sbrk_r (struct _reent * reent, ptrdiff_t incr)
|
|
{
|
|
uint32_t prev_heap_end;
|
|
|
|
// This needs to be atomic
|
|
|
|
// Disable interrupts on this core
|
|
uint32_t sr_iee = or1k_interrupts_disable();
|
|
uint32_t sr_tee = or1k_timer_disable();
|
|
|
|
// Initialize heap end to end if not initialized before
|
|
or1k_sync_cas((void*) &_or1k_heap_end, 0, (uint32_t) _or1k_heap_start);
|
|
|
|
do {
|
|
// Read previous heap end
|
|
prev_heap_end = _or1k_heap_end;
|
|
// and try to set it to the new value as long as it has changed
|
|
} while (or1k_sync_cas((void*) &_or1k_heap_end,
|
|
(uint32_t) prev_heap_end,
|
|
(uint32_t) (prev_heap_end + incr)) != (uint32_t) prev_heap_end);
|
|
|
|
// Restore interrupts on this core
|
|
or1k_timer_restore(sr_tee);
|
|
or1k_interrupts_restore(sr_iee);
|
|
|
|
return (void*) prev_heap_end;
|
|
}
|