source: rtems/doc/FAQ/debug.t @ 70b8f3ed

4.104.114.84.95
Last change on this file since 70b8f3ed was 70b8f3ed, checked in by Joel Sherrill <joel.sherrill@…>, on Jul 15, 1999 at 3:52:22 PM

Added information on hardware to aid in debugging. Primarily this is
information on gdb and bdm for the MPC8xx, MC683xx, and ColdFire?.

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1@c
2@c  COPYRIGHT (c) 1988-1998.
3@c  On-Line Applications Research Corporation (OAR).
4@c  All rights reserved.
5@c
6@c  $Id$
7@c
8
9@chapter Debugging Hints
10
11The questions in this category are hints that can ease debugging.
12
13@section How do I determine how much memory is left?
14
15First there are two types of memory: RTEMS Workspace and Program Heap.
16The RTEMS Workspace is the memory used by RTEMS to allocate control
17structures for system objects like tasks and semaphores, task
18stacks, and some system data structures like the ready chains.
19The Program Heap is where "malloc'ed" memory comes from.
20
21Both are essentially managed as heaps based on the Heap Manager
22in the RTEMS SuperCore.  The RTEMS Workspace uses the Heap Manager
23directly while the Program Heap is actually based on an RTEMS Region
24from the Classic API.  RTEMS Regions are in turn based on the Heap
25Manager in the SuperCore.
26
27@subsection How much memory is left in the RTEMS Workspace?
28
29An executive workspace overage can be fairly easily spotted with a
30debugger.  Look at _Workspace_Area.  If first == last, then there is only
31one free block of memory in the workspace (very likely if no task
32deletions).  Then do this:
33
34(gdb) p *(Heap_Block *)_Workspace_Area->first
35$3 = @{back_flag = 1, front_flag = 68552, next = 0x1e260, previous = 0x1e25c@}
36
37In this case, I had 68552 bytes left in the workspace.
38
39@subsection How much memory is left in the Heap?
40
41The C heap is a region so this should work:
42
43(gdb) p *((Region_Control *)_Region_Information->local_table[1])->Memory->first
44$9 = @{back_flag = 1, front_flag = 8058280, next = 0x7ea5b4,
45  previous = 0x7ea5b0@}
46
47In this case, the first block on the C Heap has 8,058,280 bytes left.
48
49
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