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55 lines
1.5 KiB
55 lines
1.5 KiB
/* 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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