[fpc-devel] Error building xtensa rtl

Sven Barth pascaldragon at googlemail.com
Wed Apr 1 00:06:06 CEST 2020

Christo Crause <christo.crause at gmail.com> schrieb am Di., 31. März 2020,

> On Tue, Mar 31, 2020 at 7:39 AM Sven Barth via fpc-devel <
> fpc-devel at lists.freepascal.org> wrote:
>> Am 30.03.2020 um 22:07 schrieb Christo Crause via fpc-devel:
>> I've noticed GCC uses the SLLI + SRAI instructions to perform sign
>> extension on ESP8266.
>> Since different CPUs can support different subsets of the Xtensa
>> instructions do you think a finalizecode type function can be used as a
>> post code generation step to map unsupported instructions to alternative
>> sequences?
>> These are simply different CPU types (-CpXXX or selected by the
>> controller type) which the code generator will handle accordingly. Just
>> like it's done with ARM, AVR and all other platforms.
> Attach please find a patch to rtl/embedded/MakeFile* to handle subarch
> similar to avr and others.

Did you manually edit the Makefile or regenerate it from the Makefile.fpc?
If the former then your changes at the top will be overwritten by the next
makefile regeneration.

Also attached a patch that checks whether the SEXT instruction is available
> for the current subarchitecture, else it generates SLLI + SRAI combination.

If SLLI and SRAI are supported by the other processors supported by FPC
then you don't need to check for the processor type, checking against the
capability for SEXT is enough. If some processor does not support SLLI or
SRAI either then this would need to be a capability as well.


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