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On Sun, 2001-12-23 at 02:13, Bob Koninckx wrote: > Hi guys, > > I'd like to introduce an extra configuration option into the powerPC > HAL. > The powerpc architecture allows the vectorbase to be located at > 0x00000000 > or fff00000. Not every board however has memory at 0xfff00000. Depending > on > the platform, 0x00000000 can be RAM or FLASH or ... > > Therefore I think that it makes sense to rewrite the CDL option for the > vector > base as follows. > > cdl_option CYGHWR_HAL_POWERPC_VECTOR_BASE { > display "Exception vectors location" > description " > PowerPC exception vectors can reside either at 0x00000000 or > 0xfff00000. The startup type and platform HAL controls which > is used." > flavor data > calculated { (! CYGHWR_HAL_POWERPC_FORCE_VECTOR_BASE_LOW && > (CYGHWR_HAL_POWERPC_FORCE_VECTOR_BASE_HIGH || > (CYG_HAL_STARTUP != "RAM" && > ! CYGSEM_HAL_POWERPC_COPY_VECTORS))) > ? 0xfff00000 : 0x00000000 } > } > > If the platform HAL does not define > CYGHWR_HAL_POWERPC_FORCE_VECTOR_BASE_LOW, > nothing changes, so there is no risk of breaking existing code. It > leaves however > the option to force the vector base at zero with copying (for RAM at > 0x0000) or > WITHOUT copying the vectors. (FLASH 0x0000000) > > This would be good to have for e.g. MPC555. Copying the vectors is than > usefull for > platforms that disable the internal flash and dual map it to a RAM > region. Not copying > allows for using the Internal flash. (an attempt to write to that one > will result in > an illegal instruction exception) > > Any comments, suggestions ?? This is a fine idea, as long as care is taken to not break anything :-) Do it, test it, send the patch & the [copyright] assignments and we'll integrate it into the source tree.
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