Porting/writing a Spin compiler to baremetal Raspberry Pi/Ultibo
pik33
Posts: 2,350
in Propeller 2
As I can understand, the only opensource Spin2 compiler available is Flexspin (or is there any else?)
What I want is to port a Spin(2) compiler to Ultibo environment on RPi. This will allow to connect P2 to RPi making a hardware independent from any other PCs and operating systems.
The Ultibo is a Free Pascal based environment for bare metal RPi programming. It allows to link static compiled C code as a library, if it doesn't depend on something other than libc/libm
As I can see, Flexspin is C (good...) but it is complex and have dependencies (Bison?) (bad...)
To make this work with Ultibo I have to (1) get a compiler source (2) simplify it to get rid of dependencies, if possible, (3) add a few functions to interface with Ultibo code.
The second way may be writing a Spin compiler for Ultibo from scratch in fpc.
At the moment I don't know which way can be simpler. Writing a compiler is a complex task but getting rid of dependencies in a big piece of foreign code can be even harder.
What I want is to port a Spin(2) compiler to Ultibo environment on RPi. This will allow to connect P2 to RPi making a hardware independent from any other PCs and operating systems.
The Ultibo is a Free Pascal based environment for bare metal RPi programming. It allows to link static compiled C code as a library, if it doesn't depend on something other than libc/libm
As I can see, Flexspin is C (good...) but it is complex and have dependencies (Bison?) (bad...)
To make this work with Ultibo I have to (1) get a compiler source (2) simplify it to get rid of dependencies, if possible, (3) add a few functions to interface with Ultibo code.
The second way may be writing a Spin compiler for Ultibo from scratch in fpc.
At the moment I don't know which way can be simpler. Writing a compiler is a complex task but getting rid of dependencies in a big piece of foreign code can be even harder.
Comments
This is freepascal/Lazarus based bare metal environment for RPi 0..3 called Ultibo ( www.ultibo.org). You can compile a source code on Linux or Windows machine including the Raspberry Pi. The result is kernel7.img file which you can put on a SD card with RPi firmware and it starts without any OS in less than 5 seconds. There is no OS, but there is filesystem and multitasking support in it.
Ultibo supports C compiled libraries if only they have no dependencies other than libc/libm. They can be compiled on Linux powered RPi. It doesn't support C++. I can then attach the compiled library, make the interface code and tell the linker to link it.
I ported. for example, mp3 decoder library libmad to Ultibo. The hardest thing to do with it was getting rid of all the stuff which outputs logs, error descriptions and all other stuff using and depending on several standard Linux libraries which I haven't in Ultibo and this stuff has nothing to do with the main task: get an mp3 frame and output decoded audio samples.
After stripping the library from all this stuff it worked (and I have a bare metal mp3 player on RPi which starts immediately and I can switch the Pi with the power switch at any time).
To port a command line compiler this way I need to rename its main(argc,argv) to a "non-main" function, for example int compile(arguments). Then get rid of all code not necessary for the compilation: verbose output, logging, error processing, etc) - if possible. Then compile it as a library and link it with the rest of my program.
To start this I need a Propeller board first (I am waiting for delivery of P2 development board and accessories set) and then some time to try to connect it to RPi and experiment with coding. The board was ordered 3 weeks ago, maybe a santa Postman will bring it before Christmas.
I've recently been considering integrating/building a car PC to play music using a RPi, but the lack of true sleep mode and slowish boot always turned me off. I'm interested, how fast does your custom system boot up from power on to begin playing?
You can also get fast booting with normal linux. Just don't use the default OS. Barebones distros like Arch boot very quickly. Still not as fast as bare metal firmware, obviously.
OpenSpin is a compiler for Bytecode for P1, written in C and open source. Does not support P2.
FlexSpin is the cmd line compiler used by FlexProp, the GUI needs TCL that might not work on bare bones, but the compiler itself could be doable.
Enjoy!
Mike
The (very messy) stuff is here: https://github.com/pik33/ultibo_retro_gui - it contains near all things I started and finished - or not finished and left as it it - for Ultibo - including 6502, SID and OpenGL testing stuff. I have to clean it up.
Of course if your program doesn't write on SD itself. The player only reads. You can even pull the SD out when system is up and insert another SD, it will be automounted and visible. There is no system - It is your RPi
If the source is avaliable, and it is Pascal, then porting this should be easy
Not sure if PropTool is using the x86 code tho.
Even the debug stuff contains a parser in assembly, but according to chip that might be able to be rewritten in pascal itself since it is just simple string parsing.
Mike
The assembly code has to be translated for ARM then...
I think pnut is totally x86 assembler - it's the P2 compiler. If not, then it's only the IDE that's not.
There was a lot of discussion about wanting Chip to write the P2 compiler in other than x86 but it never happened.
Don't expect to see OpenSpin2 from Roy. His work was almost wasted.
The x86 part is the same between pnut and proptool. The compilation process does a fair bit of back and forth between the delphi parts and the x86 parts of the code.
OTOH flexspin/spin2cpp is already written in C, is open source, and runs on multiple platforms including the Raspberry Pi. Porting it to Ultibo will surely be easier than porting a bunch of x86 assembly code.