Re: [edk2-devel] About EDK2 supports Self Modifying Code

["Pedro Falcato" <pedro.falcato@gmail.com>]

On Tue, Aug 15, 2023 at 4:05 PM Andrew Fish via groups.io
<afish=apple.com@groups.io> wrote:
>
> Chao,
>
> From a quick google it looks like CSR* is used to access banks of registers that relate to things like performance counters and debug infrastructure and the number of banks of these register sets is likely implementation defined. Seems like we could introduce some Fixed At Build PCD values that define the maximum number of elements in a given bank.
>
> If we are forced to use assembler it might be possible to write some macros that used the fixed at build values to only generate functions for banks that are needed for a given build. Then I think it becomes an exercise in dead code stripping the assembler. Most compilers generate assembler that contains functions that can be stripped as long as those functions follow certain rules.
>
> As a side note it would be good for us to have an FAQ/Wiki entry for the dead code stripping rules for the various flavors of assembler. I know the Apple assembler has a unique take on this.

FWIW, I'm almost positive there's no DCE in GNU as (or llvm-as as
well). Unless you use something ffunction-sections
-fdata-sections-like, but then you're relying on the linker +
gc-sections to take care of it, just like GCC/clang would.

-- 
Pedro


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