[fpc-devel] Xtensa build for ESP32 - Error: unknown opcode or format name 'dpfr'

[info-freepascal at iopen.net]

We followed the instructions on this ...

> https://wiki.freepascal.org/Xtensa

... and on the referred-to page ...

> https://docs.espressif.com/projects/esp-idf/en/stable/esp32/get-started/index.html

A considerable way through the resulting FPC build this happened ...

> Compiling ./chm/src/htmlutil.pas
> Assembling htmlutil
> Assembling chmsitemap
> chm/units/xtensa-freertos/chmsitemap.s: Assembler messages:
> chm/units/xtensa-freertos/chmsitemap.s:927: Error: unknown opcode or format name 'dpfr'
> chm/units/xtensa-freertos/chmsitemap.s:5575: Error: unknown opcode or format name 'dpfr'
> chm/units/xtensa-freertos/chmsitemap.s:9957: Error: unknown opcode or format name 'dpfr'
> chmsitemap.pas(866) Error: Error while assembling exitcode 1
> chmsitemap.pas(866) Fatal: There were 2 errors compiling module, stopping
> Fatal: Compilation aborted
> 
> The installer encountered the following error:
> Compilation of "units/xtensa-freertos/BuildUnit_chm.pp" failed
>   $0000000000539999
>   $00000000005449FB
>   $0000000000543891
>   $0000000000544D31
>   $000000000054843A
>   $0000000000538112
>   $0000000000538824
>   $0000000000487426

FPC source used was downloaded at UTC 19:05 2026-02-13, and the ESP IDF
is v5.5.2

Get the same behaviour with ESP IDF v5.0.9.

Platform is AlmaLinux 10 x86.

*****

Not related to the above, but possibly relevant when compiling for
ESP32. On the FP Xtensa page are mentioned files esp32_out.ld and
esp32.project.ld, but neither exists on the development machine.

*****

We're aware of the FP Xtensa page saying "Warning: The Xtensa support is
highly experimental and prone to be broken. This description is work in
progress."

Being able to use FP for producing ESP32 apps will make a huge
productivity difference, compared with the alternatives. With the Xtensa
build there's too many unknowns for us to handle in the forseeable future.

A possible alternative is to run a Z80 emulator plus an I/O layer on the
ESP32, and either configure FP to generate Z80 code or revive TP3/80.

Cheers
IOPEN Devels