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Restarting program - Requires reload when running from RAM?

Vasili Galka
Expert 2690 points

Hi,

I'm debugging some code on AM335x using XDS100v2 JTAG emulator. I load the code to DDR RAM using the debugger and then run it.

As far as I understand, to restart the program I have to pause, reset and then reload the program, otherwise initialized static variables don't get their initial values. Is this the only right way or I miss something?

Regards,
Vasili

  • 0
    Guru 192875 points

    Hi,

    Static variables can be altered using the Watch window. You can load the variables onto the watch window and then alter them while debugging. 

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Expert 2690 points

    Hmm, I probably explained myself poorly... I'm not interested in changing static variables by hand. What I mean, when the program runs - it changes their values, but when I restart the program - I need their values to be restored to initial.

  • 0 in reply to Vasili Galka
    Guru 192875 points

    Hi,

    Oh, but when you restart the program the variables do get initialized to their initial values. I guess you're talking about the restart program during debugging session, right?

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Expert 2690 points

    Right. That's why I put it on the CCS forum :-)

  • 0
    Guru 92251 points

    Vasili Galka said:
    I'm debugging some code on AM335x using XDS100v2 JTAG emulator. I load the code to DDR RAM using the debugger and then run it.

    As far as I understand, to restart the program I have to pause, reset and then reload the program, otherwise initialized static variables don't get their initial values. Is this the only right way or I miss something?

    Assuming you are using the TI ARM linker, it depends on the Linker Initialization Model (selected under CCS Project Properties -> Build -> ARM Linker -> Advanced Options -> Runtime Environment).

    With "Link using RAM autoinitialization model" the static variables will only get their initial values when the program is re-loaded into memory by CCS.

    With "Link using ROM autoinitialization model" the linker inserts start-up code to initialize the static variables with their initial values. In this case restarting the program in the CCS debugger will re-run the start-up code to re-initialize the static variables with their initial values. The downside is an increase in memory usage.

  • 0 in reply to Chester Gillon
    Expert 2690 points

    Oh, that is interesting! But if I use "RAM autoinitialization model" I have to reload the image each time?
    Is there such linker option for GNU linker too? I'm using GCC toolchain and not TI's.

  • 0 in reply to Vasili Galka
    Guru 92251 points

    Vasili Galka said:
    Is there such linker option for GNU linker too? I'm using GCC toolchain and not TI's.

    Looking at the gcc-arm-none-eabi-4_7-2012q4 toolchain which comes with CCS 5.5 I can't see such a linker option.

    Think that with the GCC toolchain you have to modify the linker script .lds file and the initialization assembler to get the equivalent of the "ROM autoinitialization model" TI linker option.