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