[fpc-devel] Error building xtensa rtl

Florian Klämpfl florian at freepascal.org
Sun Mar 29 23:00:11 CEST 2020

Am 29.03.20 um 22:46 schrieb Christo Crause via fpc-devel:
> According to the Xtensa ISA 4.3.8 the SEXT instruction is optional (and 
> some others too) and apparently not implemented for ESP8266 according to 
> core-isa.h in ESP8266_RTOS_SDK 
> (https://github.com/espressif/ESP8266_RTOS_SDK/blob/master/components/esp8266/include/xtensa/config/core-isa.h).  
> This explains why xtensa-lx106-elf-as does not recognise the SEXT 
> instruction.
> It seems that a different instruction sequence should be used for sign 
> extension for the lx106 subarch.

Ok, I see. Let me first integrate everything done so far in trunk, then 
we can continue with the details :)

> Also core-isa.h indicates XCHAL_HAVE_WINDOWED = 0, which I take to mean 
> that the LX106 toolchain doesn't know/implement the windowed ABI, which 
> explains why setting the FPC ABI to windowed caused as to flag retw as 
> unknown.

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