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56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
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/* sbrk.c -- allocate memory dynamically.
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*
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* Copyright (c) 1995,1996 Cygnus Support
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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 <errno.h>
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#include "glue.h"
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/* just in case, most boards have at least some memory */
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#ifndef RAMSIZE
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# define RAMSIZE (caddr_t)0x100000
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#endif
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char *heap_ptr;
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/*
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* sbrk -- changes heap size size. Get nbytes more
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* RAM. We just increment a pointer in what's
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* left of memory on the board.
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*/
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char *
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sbrk (nbytes)
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int nbytes;
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{
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char *base;
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if (!heap_ptr)
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heap_ptr = (char *)&_end;
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base = heap_ptr;
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heap_ptr += nbytes;
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return base;
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/* FIXME: We really want to make sure we don't run out of RAM, but this
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* isn't very portable.
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*/
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#if 0
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if ((RAMSIZE - heap_ptr - nbytes) >= 0) {
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base = heap_ptr;
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heap_ptr += nbytes;
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return (base);
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} else {
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errno = ENOMEM;
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return ((char *)-1);
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}
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#endif
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}
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