From 93b4e6ef7ea97190a1d542191e78e287a3b540f4 Mon Sep 17 00:00:00 2001
From: Joel Sherrill <joel.sherrill@OARcorp.com>
Date: Tue, 2 Nov 1999 21:05:17 +0000
Subject: Split Heap and Time of Day Handlers.

---
 cpukit/score/src/heapextend.c | 113 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 cpukit/score/src/heapextend.c

(limited to 'cpukit/score/src/heapextend.c')

diff --git a/cpukit/score/src/heapextend.c b/cpukit/score/src/heapextend.c
new file mode 100644
index 0000000000..38b74e66e2
--- /dev/null
+++ b/cpukit/score/src/heapextend.c
@@ -0,0 +1,113 @@
+/*
+ *  Heap Handler
+ *
+ *  COPYRIGHT (c) 1989-1998.
+ *  On-Line Applications Research Corporation (OAR).
+ *  Copyright assigned to U.S. Government, 1994.
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.OARcorp.com/rtems/license.html.
+ *
+ *  $Id$
+ */
+
+
+#include <rtems/system.h>
+#include <rtems/score/sysstate.h>
+#include <rtems/score/heap.h>
+
+/*PAGE
+ *
+ *  _Heap_Extend
+ *
+ *  This routine grows the_heap memory area using the size bytes which
+ *  begin at starting_address.
+ *
+ *  Input parameters:
+ *    the_heap          - pointer to heap header.
+ *    starting_address  - pointer to the memory area.
+ *    size              - size in bytes of the memory block to allocate.
+ *
+ *  Output parameters:
+ *    *amount_extended  - amount of memory added to the_heap
+ */
+
+Heap_Extend_status _Heap_Extend(
+  Heap_Control        *the_heap,
+  void                *starting_address,
+  unsigned32           size,
+  unsigned32          *amount_extended
+)
+{
+  Heap_Block        *the_block;
+  unsigned32        *p;
+  
+  /*
+   *  The overhead was taken from the original heap memory.
+   */
+
+  Heap_Block  *old_final;
+  Heap_Block  *new_final;
+
+  /*
+   *  There are five possibilities for the location of starting
+   *  address:
+   *
+   *    1. non-contiguous lower address     (NOT SUPPORTED)
+   *    2. contiguous lower address         (NOT SUPPORTED)
+   *    3. in the heap                      (ERROR)
+   *    4. contiguous higher address        (SUPPORTED)
+   *    5. non-contiguous higher address    (NOT SUPPORTED)
+   *
+   *  As noted, this code only supports (4).
+   */
+
+  if ( starting_address >= (void *) the_heap->start &&        /* case 3 */
+       starting_address <= (void *) the_heap->final
+     )
+    return HEAP_EXTEND_ERROR;
+
+  if ( starting_address < (void *) the_heap->start ) {  /* cases 1 and 2 */
+
+      return HEAP_EXTEND_NOT_IMPLEMENTED;               /* cases 1 and 2 */
+
+  } else {                                              /* cases 4 and 5 */
+
+    the_block = (Heap_Block *)
+       _Addresses_Subtract_offset( starting_address, HEAP_OVERHEAD );
+    if ( the_block != the_heap->final )
+      return HEAP_EXTEND_NOT_IMPLEMENTED;                   /* case 5 */
+  }
+
+  /*
+   *  Currently only case 4 should make it to this point.
+   *  The basic trick is to make the extend area look like a used
+   *  block and free it.
+   */
+
+  *amount_extended = size;
+
+  old_final = the_heap->final;
+  new_final = _Addresses_Add_offset( old_final, size );
+  /* SAME AS: _Addresses_Add_offset( starting_address, size-HEAP_OVERHEAD ); */
+
+  the_heap->final = new_final;
+
+  old_final->front_flag = 
+  new_final->back_flag  = _Heap_Build_flag( size, HEAP_BLOCK_USED );
+  new_final->front_flag = HEAP_DUMMY_FLAG;
+
+  /*
+   *  Must pass in address of "user" area
+   *  So add in the offset field.
+   */
+
+  p = (unsigned32 *) &old_final->next;
+  *p = sizeof(unsigned32);
+  p++;
+  _Heap_Free( the_heap, p );
+  
+  return HEAP_EXTEND_SUCCESSFUL;
+}
+
-- 
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