[ECOS] Running application from RAM without Redboot

[Jerome Souquieres]

  Hi,

  I would like to have some advice about how to fit my specific need 
within the eCos structure.

  I have written a package derived from hal\mips\idt79s334a for my own 
CPU board (IDT32334 MIPS-based microprocessor). So far, so good. 
However, the way my application is launched is a bit peculiar: I have a 
ROM monitor (which is NOT Redboot and which I cannot change) that simply 
loads an hex file at a fixed address in RAM (0x80200000, should that 
matter). However, to build my application under eCos, I'm in trouble to 
choose the startup option:
- CYG_HAL_STARTUP_ROM: is not available for my target. No more discussion.
- CYG_HAL_STARTUP_ROMRAM: not suitable. I don't need all code to be 
copied from RAM to ROM, I don't want the SDRAM controller to be 
configured (because it is obsviously already configured at this point 
since I'm running from RAM), I don't want the exception vectors to be 
located in ROM, etc...
- CYG_HAL_STARTUP_RAM: almost suitable,but this configuration relies on 
Redboot to provide exception vectors.

  For now, what I've done is tweaking the CYG_HAL_STARTUP_RAM 
configuration so that it takes control of exception vectors. This works, 
but is a bit rough because I've somewhat changed the semantics of 
CYG_HAL_STARTUP_RAM.

  Could an eCos architect give me a hint for a proper implementation ? 
Should I create my own CYG_HAL_STARTUP_xxx ? Should I add a sub-option ? 
Another idea ?

  Thanks in advance,

  Jerome Souquieres


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss