Re: [Tinycc-devel] Resources/questions for porting?

[KHMan]

On 9/26/2017 11:36 AM, Daniel Glöckner wrote:
> Forgive me the brevity of my reply, but I should be asleep right now.
>
> On Mon, Sep 25, 2017 at 09:16:12PM -0400, Charles Lohr wrote:
> > To do this, I need to port TCC to xtensa specifically lx6 with no floating
> > point.
>
> It won't be easy to support floating point without floating point
> registers. TinyCC is not prepared to keep floating point values in
> integer registers. And you will need a soft float library like libgcc
> that probably can't be built with TinyCC unless you also implement an
> assembler.

Not a problem, the aforementioned ESP8266 is a hobbyist IoT 
favourite. Standard toolchain is gcc and newlib.

For a C app in firmware, most things can be done without floating 
point. Most old skool embedded coders will be doing fixed-point 
calculations. However, there are a few scripting platforms for 
ESP8266 (and more coming up), and platforms want to offer the most 
convenient scripting environment for possibly first-time coders 
who just want to get down to writing their app. So floats can be 
desirable or critical, depending on your target app demographic.

For NodeMCU on ESP8266, they should switch to Lua 5.3 and so avoid 
floats by using integers as much as possible while possibly 
retaining convenient float capability with a library such as 
Berkeley SoftFloat. For MicroPython, last I checked they didn't 
seem to be in a hurry to implement floats.

One advantage of tcc on ESP8266 would be that even the current tcc 
code quality will be much faster than Python or Lua scripts 
running on a VM.

References for convenience:

https://en.wikipedia.org/wiki/ESP8266
https://github.com/esp8266/esp8266-wiki/wiki/Toolchain
https://github.com/pfalcon/esp-open-sdk

https://docs.micropython.org/en/latest/esp8266/esp8266/general.html
https://en.wikipedia.org/wiki/MicroPython

https://en.wikipedia.org/wiki/NodeMCU
https://github.com/nodemcu/nodemcu-firmware

--
Cheers,
Kein-Hong Man (esq.)
Selangor, Malaysia