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User forums => Using Code::Blocks => Topic started by: pooh on May 12, 2012, 07:47:50 pm

Title: CPU registers not shown in debug window
Post by: pooh on May 12, 2012, 07:47:50 pm

Hi,

I have manged to build a GNU-cross-toolchain for MIPS under MSYS.
And I am using GDB 7.4 for remote debugging.
But I think my problem is not related to any embedded target ...

I am facing this "simple" problem:
When activating the "CPU registers" debug window it doesn't contain anything.

I have already checked the debuggers log. GDB seems to transmit something useful to C::B
In the debugger log window I get:

> info registers
          zero       at       v0       v1       a0       a1       a2       a3
 R0   00000000 00000000 00000001 00000000 00000000 00000000 00000000 00000000
            t0       t1       t2       t3       t4       t5       t6       t7
 R8   00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
            s0       s1       s2       s3       s4       s5       s6       s7
 R16  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
            t8       t9       k0       k1       gp       sp       s8       ra
 R24  00000000 00000000 00000000 00000000 00007170 00017198 00017198 00000000
            sr       lo       hi      bad    cause       pc
      00000000 00000000 00000000 00000000 00000009 00000128
           fsr      fir
      00000001 00000001

BTW: Other debug windows work fine (e.g. Examine Memory or Disassembly)

Why doesn't C::B show a copy of the GDB output??? Any idea what's wrong here?
I appreciate any help!
Thanks, guys!

Title: Re: CPU registers not shown in debug window
Post by: pooh on May 13, 2012, 08:01:18 am

Solved:
After digging into the C::B source code, I tried to set the disassembly flavor (Settings->Compiler and Debugger->Debugger Settings) to custom flavor "or32"... And that's it! Now I the registers are shown in the debug window.

Title: Re: CPU registers not shown in debug window
Post by: oBFusCATed on May 14, 2012, 10:22:13 am

Patch?

Title: Re: CPU registers not shown in debug window
Post by: MortenMacFly on May 14, 2012, 02:06:04 pm

Quote from: oBFusCATed on May 14, 2012, 10:22:13 am

Patch?

What patch? It's an option IMHO...?!

Title: Re: CPU registers not shown in debug window
Post by: oBFusCATed on May 14, 2012, 02:39:05 pm

I though he had modified the code, but as you said there is an option to specify a string...

But if it is a common flavor it will be good to add it.

Title: Re: CPU registers not shown in debug window
Post by: pooh on May 16, 2012, 09:29:07 pm

Here is the full story:
1.
There is the option to select or32 (i.e. OpenRisc from opencores.org) in my C::B distribution which is the "normal" 10.05.
So, no need to patch C::B.
(Apparently, or32 has found it's way into the official C::B sources...)

2.
I was a bit too enthusiastic when posting that I solved the issue. Actually, selecting or32 was just a first step in the right direction...
It turned out the C::B was confused by "R0", "R8" etc in front of the register value columns. Moreover, mips-gdb puts out a space at the end of the register value row, which seems to be another cause for a mismatch in the displayed register values (e.g. R1 gets the value of R0 and so on)

I tried (just a quick hack) to patch the code for the debugger DLL of C::B. This failed because C::B wasn't able to load my newly created DLL (didn't dig into details here).

Finally, I decided to patch the gdb source for MIPS.

And now it works with the or32 selection in C::B AND the patched mips-gdb.

Perhaps not the most elegant solution - but it works ;-)