source: rtems/cpukit/score/src/heap.c @ 7fa97181

Last change on this file since 7fa97181 was a6eef8b, checked in by Joel Sherrill <joel.sherrill@…>, on 09/04/03 at 18:52:48

2003-09-04 Joel Sherrill <joel@…>

  • apiext.c, chain.c, coremsg.c, coremsgbroadcast.c, coremsgclose.c, coremsgflush.c, coremsgflushsupp.c, coremsgflushwait.c, coremsginsert.c, coremsgseize.c, coremsgsubmit.c, coremutex.c, coremutexflush.c, coremutexseize.c, coremutexsurrender.c, coresem.c, coresemflush.c, coresemseize.c, coresemsurrender.c, coretod.c, coretodset.c, coretodtickle.c, coretodtoseconds.c, coretodvalidate.c, heap.c, heapallocate.c, heapextend.c, heapfree.c, heapgetinfo.c, heapsizeofuserarea.c, heapwalk.c, interr.c, isr.c, mpci.c, object.c, objectallocate.c, objectallocatebyindex.c, objectclearname.c, objectcomparenameraw.c, objectcomparenamestring.c, objectcopynameraw.c, objectcopynamestring.c, objectextendinformation.c, objectfree.c, objectget.c, objectgetbyindex.c, objectgetisr.c, objectgetnext.c, objectgetnoprotection.c, objectinitializeinformation.c, objectmp.c, objectnametoid.c, objectshrinkinformation.c, thread.c, threadchangepriority.c, threadclearstate.c, threadclose.c, threadcreateidle.c, threaddelayended.c, threaddispatch.c, threadevaluatemode.c, threadget.c, threadhandler.c, threadidlebody.c, threadinitialize.c, threadloadenv.c, threadmp.c, threadq.c, threadqdequeue.c, threadqdequeuefifo.c, threadqdequeuepriority.c, threadqenqueue.c, threadqenqueuefifo.c, threadqenqueuepriority.c, threadqextract.c, threadqextractfifo.c, threadqextractpriority.c, threadqextractwithproxy.c, threadqfirst.c, threadqfirstfifo.c, threadqfirstpriority.c, threadqflush.c, threadqtimeout.c, threadready.c, threadreset.c, threadresettimeslice.c, threadrestart.c, threadresume.c, threadrotatequeue.c, threadsetpriority.c, threadsetstate.c, threadsettransient.c, threadstackallocate.c, threadstackfree.c, threadstart.c, threadstartmultitasking.c, threadsuspend.c, threadtickletimeslice.c, threadyieldprocessor.c, userext.c, watchdog.c, watchdogadjust.c, watchdoginsert.c, watchdogremove.c, watchdogtickle.c, wkspace.c: URL for license changed.
  • Property mode set to 100644
File size: 2.8 KB
Line 
1/*
2 *  Heap Handler
3 *
4 *  COPYRIGHT (c) 1989-1999.
5 *  On-Line Applications Research Corporation (OAR).
6 *
7 *  The license and distribution terms for this file may be
8 *  found in the file LICENSE in this distribution or at
9 *  http://www.rtems.com/license/LICENSE.
10 *
11 *  $Id$
12 */
13
14
15#include <rtems/system.h>
16#include <rtems/score/sysstate.h>
17#include <rtems/score/heap.h>
18
19/*PAGE
20 *
21 *  _Heap_Initialize
22 *
23 *  This kernel routine initializes a heap.
24 *
25 *  Input parameters:
26 *    the_heap         - pointer to heap header
27 *    starting_address - starting address of heap
28 *    size             - size of heap
29 *    page_size        - allocatable unit of memory
30 *
31 *  Output parameters:
32 *    returns - maximum memory available if RTEMS_SUCCESSFUL
33 *    0       - otherwise
34 *
35 *    This is what a heap looks like in memory immediately
36 *    after initialization:
37 *
38 *            +--------------------------------+
39 *     0      |  size = 0      | status = used |  a.k.a.  dummy back flag
40 *            +--------------------------------+
41 *     4      |  size = size-8 | status = free |  a.k.a.  front flag
42 *            +--------------------------------+
43 *     8      |  next     = PERM HEAP_TAIL     |
44 *            +--------------------------------+
45 *    12      |  previous = PERM HEAP_HEAD     |
46 *            +--------------------------------+
47 *            |                                |
48 *            |      memory available          |
49 *            |       for allocation           |
50 *            |                                |
51 *            +--------------------------------+
52 *  size - 8  |  size = size-8 | status = free |  a.k.a.  back flag
53 *            +--------------------------------+
54 *  size - 4  |  size = 0      | status = used |  a.k.a.  dummy front flag
55 *            +--------------------------------+
56 */
57
58unsigned32 _Heap_Initialize(
59  Heap_Control        *the_heap,
60  void                *starting_address,
61  unsigned32           size,
62  unsigned32           page_size
63)
64{
65  Heap_Block        *the_block;
66  unsigned32         the_size;
67
68  if ( !_Heap_Is_page_size_valid( page_size ) ||
69       (size < HEAP_MINIMUM_SIZE) )
70    return 0;
71
72  the_heap->page_size = page_size;
73  the_size = size - HEAP_OVERHEAD;
74
75  the_block             = (Heap_Block *) starting_address;
76  the_block->back_flag  = HEAP_DUMMY_FLAG;
77  the_block->front_flag = the_size;
78  the_block->next       = _Heap_Tail( the_heap );
79  the_block->previous   = _Heap_Head( the_heap );
80
81  the_heap->start          = the_block;
82  the_heap->first          = the_block;
83  the_heap->permanent_null = NULL;
84  the_heap->last           = the_block;
85
86  the_block             = _Heap_Next_block( the_block );
87  the_block->back_flag  = the_size;
88  the_block->front_flag = HEAP_DUMMY_FLAG;
89  the_heap->final       = the_block;
90
91  return ( the_size - HEAP_BLOCK_USED_OVERHEAD );
92}
93
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