Problem of ldr file without the use of the default kernel

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Problem of ldr file without the use of the default kernel

Post  lyh8 on Wed Apr 01, 2009 7:48 pm

In my SHARC application created in VisualDSP++ v5.0, I found a problem in my ldr file when "Use default kernel" option was unchecked in the Project Option window. The problem was the ldr image did not contain an Interrupt Vector Table at the end. Because of that, the ldr image failed to run after being loaded from flash to on-chip RAM. Can you please advise why? Thanks a lot.

lyh8

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Re: Problem of ldr file without the use of the default kernel

Post  lzmind on Mon Apr 06, 2009 10:37 am

Hi lyh8, the option "No default kernel" could be misleading. One might think that the option omits only the default kernel from the top of the ldr file. In fact, the IVT table was also omitted from the bottom of the ldr file. The reason of making the ldr file that way was that the option was intended to be used for the internal mode, in which mode, the processor starts executing the application stored in the internal boot kernel upon reset; the boot stream is not imported by a boot kernel executing from within the IVT space; no self-modifying FINAL_INIT code (which overwrites itself with the IVT) is needed. Thus, the loader utility does not give any special handling to the 256 instructions located in the IVT.

Thus, if your application is stored in external flash memory, it is recommended to check the option in your project load option. In case you don't need the default kernel located at the top of your ldr file when the boot stream is imported, skip the 256 48-bit words from the image in your flash memory.

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