60 lines
1.5 KiB
C
60 lines
1.5 KiB
C
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/*
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* Copyright (c) 2003 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use, modify,
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* copy, or redistribute it subject to the terms and conditions of the BSD
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* License. This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY expressed or implied, including the implied
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* warranties of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. A copy
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* of this license is available at http://www.opensource.org/licenses. Any
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* Red Hat trademarks that are incorporated in the source code or documentation
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* are not subject to the BSD License and may only be used or replicated with
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* the express permission of Red Hat, Inc.
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*/
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#include <errno.h>
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extern int __heap __far; /* beginning of heap */
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extern int __heap_end __far; /* if at address 0, use stack pointer as limit */
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static char *the_break = (char *)(& __heap);
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int
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is_addr_0 (int address)
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{
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return address ? 0 : 1;
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}
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void *
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sbrk(int inc)
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{
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char *current_heap_limit = (char *) (& __heap_end);
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/* is_addr_0 avoids optimizing out this block. */
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if (is_addr_0 ((int) current_heap_limit))
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{
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int something;
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int margin = 4096;
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current_heap_limit = (char *) (& something) - margin;
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}
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if ((the_break + inc) < current_heap_limit)
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{
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void *rv = (void *) the_break;
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the_break += inc;
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return rv;
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}
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else
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{
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errno = ENOMEM;
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return (void *) -1;
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}
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}
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int
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brk (void *ptr)
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{
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the_break = ptr;
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return 0;
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}
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