ARM946E-S attempt (gdb patches / insight)

Smith, Gene SEA Gene.Smith at
Tue Aug 12 21:36:22 UTC 2008

How do you set the compile option to -O0 so it takes effect everywhere
(building rtems and your app)?  

-----Original Message-----
From: rtems-users-bounces at
[mailto:rtems-users-bounces at] On Behalf Of Joel Sherrill
Sent: Monday, March 24, 2008 4:24 PM
To: gds
Cc: rtems-users at
Subject: Re: ARM946E-S attempt (gdb patches / insight)

gds wrote:
> In my attempt to build an ARM946E-S bsp I hijacked the existing csb337
> bsp as a starting point. I have built an arm-rtems4.8-insight debugger
> in addition to the standard gdb. However, I never applied the rtems
> gdb6.6 patches to the insight 6.6 tree. Are they needed with insight?
> Anyhow, when running insight debugger I seems that, in "mixed mode", I
> don't always see the assembly instructions associated with the correct
> source line. The order seems somewhat random and jumps around when I
> step. In the attached example you can see that the instructions
> associated with a c source line are not always sequentially
> Would that be expected with arm architecture, which I have not worked
> with before? Would lack of rtems patches affect this?
It isn't an RTEMS issue.  With optimized code on RISC CPUs,
the assembly from multiple source lines might be intermixed
for performance reasons.  I know the PowerPC and SPARC are
pretty aggressive about this and it can be VERY frustrating.

Some people compile at -O0 when things to make this phase
of debugging easier.  But remember, your code may break
again at -O2 especially in the case of missing volatiles.
> The code shown in ex.txt is from bspstart.c.
> -gene

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