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C55x large memory model

I'd like to confirm my understanding of the C55x large memory model.

SPRU281F says that large model data sections must fit in one 64K word page. So for the .bss say, there can be no more than 64K words of uninitialized statically allocated objects, unless you start using #pragma DATA_SECTION to put some of them in other sections.

In SPRU281G this restriction is not mentioned. Can I take this to mean that:

1. there is a change for tools version 4.4,

2. data sections can exceed a page in size,

3. the linker will automatically allocate objects to different pages, preventing them from crossing page boundaries unless compiled for CPU 3,

4. there is no longer a need to use #pragma DATA_SECTION to exceed 64K words of statically allocated objects and

5. the .sysmem malloc arena total size can exceed a page?

 

  • It is still true that large model data sections must fit in one 64K word page.  It is a mistake in the new book (SPRU281G) that this is not mentioned.  This doesn't answer all of your questions.  I'll continue to ping the experts on the rest.

    Thanks and regards,

    -George

  • George is correct that it is a mistake that the current Compiler Users Guide (SPRU281G) no longer explicitly metnions that data sections must fit in one 64K word page.  I think you probably correctly inferred the answers to all of your questions, but just to be sure...

    The answers to the rest of your questions all are  "No".