[openrisc] Debugging application

["Robert Cragie" <rcc@jennic.com>]

I have got GDB running with my target OK now - all I needed to do was put a
breakpoint() call in at cyg_start, thanks for that, Gary. I can single step
OK but I cannot inspect data properly for some reason.

The versions of the debugger and the compiler are as follows:

GNU gdb 5.0
Copyright 2000 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "--host=i686-pc-linux-gnu --target=or32-elf".

or32-elf-gcc (GCC) 3.2.3
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

The application was compiled with:

or32-elf-gcc -g -I../include hello.c -L../lib -o hello -Ttarget.ld -nostdlib

I get the following:

569         HAL_BREAKPOINT(_breakinst);
(gdb) step
Sending packet: $Hc0#db...Ack
Packet received:
Sending packet: $s#73...Ack
Packet received: T0540:000063ec;01:000093dc;
Sending packet: $s#73...Ack
Packet received: T0540:000013fc;01:000093e0;
Sending packet: $g#67...Ack
Packet received:
000093dc000093e0000000ff000000ff9100001400000002000083fc00000001000000010000
13fc000000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000013fc00008201
cyg_start () at hello.c:72
72              ulMask = 1;
(gdb) step
Sending packet: $s#73...Ack
Packet received: T0540:00001400;01:000093e0;
Sending packet: $s#73...Ack
Packet received: T0540:00001404;01:000093e0;
Sending packet: $g#67...Ack
Packet received:
000093dc000093e0000000ff000000019100001400000002000083fc00000001000000010000
13fc000000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000140400008201
73              for (ulOffset = 0; ulOffset <= 5; ulOffset++)
(gdb) print ulMask
Sending packet: $mcf,4#96...Ack
Packet received: 00000000
$1 = 0
(gdb) print my_data
Address of symbol "my_data" is unknown.
(gdb) print _my_data
Sending packet: $m835c,4#d0...Ack
Packet received: 00000002
$2 = 2
(gdb)

Code snippet:

int my_data = 2;
void cyg_start(void)
{
    unsigned long ulMask;

    breakpoint();

    for(;;)
    {
        ulMask = 1;
[snip]

So the data in the auto variable 'ulMask' should be 1 and is being reported
as '0', it cannot find the address of 'my_data' but correctly reports the
contents if I specify it as '_my_data' as it appears in the symbol table.

Is it possible that there is an incompatibility with GCC 3.2.3 and GDB 5.0?
GDB 5.0 is rather old now. If so, do I need to try to use a later version of
GDB with OpenRISC additions?

I'd appreciate any help on this matter.

Robert Cragie, Design Engineer
_______________________________________________________________
Jennic Ltd, Furnival Street, Sheffield, S1 4QT,  UK
http://www.jennic.com  Tel: +44 (0) 114 281 2655
_______________________________________________________________

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