Integrating Raspberry Baremetal build

[msx80]

Hi there, to continue discussion on #907 , i made some tests and updated the build of my baremetal port to the latest TIC80 sources.

In the end, modifications on the codebase is limited to the following:

• fs.c: this is the biggest change, most of the primitive functions in here need a different implementation.
• tic80_types.h: need changes to avoid a type conflict.
• CMakeList.txt: a block for Baremetal is added at the beginning as a preamble, to set all variables etc.

Everything else is new files that could go in any folder.
The strategy i used is to build tic80lib as usual (i haven't added a new target) with BAREMETAL switch, which is basically just crosscompiling it to ARM with some custom stuff for RPI. Then i made a separate program (the kernel), based on circle examples code, that link to the tic80lib.a. This is a separate Makefile that include stuff from circle and circle-stdlib, not sure it is possible to include it in the main CMake build file.

I think we could put the kernel on src/system/baremetalrpi and the Makefile on build/baremetalrpi, or some similar combination. In build/baremetalrpi i can put a readme with all steps to checkout circle and build everything.

If you're ok i can prepare a pull request (in a couple of weeks, i'm leaving for vacation soon :D ). Obviously everything can be changed later if we find a better fit.

I was able to build TIC80 with all languages except squirrel (for some reason it breaks crosscompilation, i think it has some dangling arm switch inside somewhere).

[nesbox]

Sounds awesome, as for fs.c I think we could make some kind of abstraction layer for the file system operations, will do after your PR...
Thank you.

[nesbox]

will setup CI scripts soon
thanks

[msx80]

Hi there, you may want to wait for my next pr (with some more hardware support) before setting up ci, as the building instructions have changed a little

[nesbox]

Hi,
I tried to setup CI for the bare-metal build but with no success, seems we are a bit outdated with the Circle repo now.
@msx80 could you pls look at?
Thank you.

[msx80]

Hi there, i'll take a look! With RPi4 and RPI400 it starts to get interesting.
But i'll take some time as i'm a bit busy lately..

[nesbox]

Hi, thank you 👍

[msx80]

I gave a try, i've updated some stuff and can compile some of the libs, but zip is giving me errors.

In file included from /home/nicola/TIC-80/vendor/zip/src/zip.c:47: /home/nicola/TIC-80/vendor/zip/src/miniz.h: In function 'mz_zip_set_file_times': /home/nicola/TIC-80/vendor/zip/src/miniz.h:4479:11: error: implicit declaration of function 'utime'; did you mean 'ctime'? [-Werror=implicit-function-declaration] 4479 | return !utime(pFilename, &t); | ^~~~~ | ctime cc1: all warnings being treated as errors

Seems some shenanigans with utime.h. In miniz.h there's a switch that seems to be added just for that (MINIZ_NO_TIME), but if i define it, some other things break:

In file included from /home/nicola/TIC-80/vendor/zip/src/zip.c:47: /home/nicola/TIC-80/vendor/zip/src/miniz.h: In function 'mz_zip_writer_add_file': /home/nicola/TIC-80/vendor/zip/src/miniz.h:6331:8: error: implicit declaration of function 'mz_zip_get_file_modified_time' [-Werror=implicit-function-declaration] 6331 | if (!mz_zip_get_file_modified_time(pSrc_filename, &file_modified_time)) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [...]

I'm not sure what to make of it, seems like it doesn't handle the switch correctly as it still uses some functions that are switched off. I've tried to update to the latest version of the library but the behaviour doesn't change.

I'll look deeper into it when i'll have some more time, in the meantime i report the progress, if anyone has some idea it's welcome :D