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FlexProp: a complete programming system for P2 (and P1)

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  • RaymanRayman Posts: 14,033

    Think I found the problem using WinDiff...

    Seems it's been a year since I touched this and back then, I did a hack to make the code work with both PropTool and FlexProp.
    But, seems this fix didn't propagate to all my setups...

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  • RaymanRayman Posts: 14,033

    Seems the above hack no longer works...

    Fixed for the moment like this:

    PUB Read8(Dpin, Cpin): Value|Dpin2, CPin2, pValue 'read 8 bits
        'Note:  24Dec22:  Had to adapt code to work with both FlexProp and PropTool.
        '       FlexProp puts Value before Dpin in memory, but PropTool leaves Value after Cpin
        pValue:=Value:=@Value 'This way, the third variable will have @Value in both FlexProp and PropTool
        Dpin2:=Dpin
        Cpin2:=Cpin
        SendCommand(Read8_,@Dpin2)
        'wait for this command to finish
        repeat
        until command==0
        return Value
    
  • RaymanRayman Posts: 14,033

    Actually, seems like the hack still works, just didn't implement everywhere, what a mess...

  • ElectrodudeElectrodude Posts: 1,631
    edited 2023-11-04 05:10

    @Rayman said:
    Actually, seems like the hack still works, just didn't implement everywhere, what a mess...

    This is what Git is for... Whatever investment of time it may cost to learn is well worth always knowing exactly how all the copies on each of your computers differ from what you expect.

  • RaymanRayman Posts: 14,033

    It is actually there: https://github.com/GitRayman/Antares/blob/main/SPI.spin2

    Looks like didn't check in the fix though...

  • @ersmith said:

    @Rayman said:
    I'm a bit surprised that the compiler doesn't give a warning when initializing a static structure with index beyond what is declared...

    That's fairly common for C compilers (C actually lets you index wherever you want in an array, and it's up to you to make sure it's within bounds). That said, I will add a warning for this case (it'll be useful for BASIC, where you really shouldn't be trying to reference an array out of bounds).

    I'm not convinced about the warning for C. I've often implemented variable-sized arrays by having a structure with a length field and an array of size 1. Then I dynamically allocate enough memory to hold as many elements as I need and use the length field in the structure to bounds check an index at runtime. Something like this:
    typedef struct { int length; int data[1]; } DynamicIntArray;
    I would make the array zero length but that is usually not allowed by C compilers. Anyway, I would hate to get a warning every time I use this technique. I try to make sure my code compiles without any warnings and it's not clear how I would get around this one.

    On another note, how many people here are using C on the P2? From looking at the posts it seems most people are using Spin, PASM, or Basic.

  • @"David Betz" said:
    I would make the array zero length but that is usually not allowed by C compilers.

    The correct way is to actually leave the size field empty, like int data[]. The funny name for this is "flexible array member" and it's part of C99. I am not sure of flexC actually takes it.

  • @Wuerfel_21 said:

    @"David Betz" said:
    I would make the array zero length but that is usually not allowed by C compilers.

    The correct way is to actually leave the size field empty, like int data[]. The funny name for this is "flexible array member" and it's part of C99. I am not sure of flexC actually takes it.

    I don’t think the version of C I was using at the time supported that. I mostly use C++ these days.

  • evanhevanh Posts: 15,278

    @"David Betz" said:
    On another note, how many people here are using C on the P2? From looking at the posts it seems most people are using Spin, PASM, or Basic.

    I both prefer and use C myself. But since Flexspin has not problem integrating multiple languages in one build, I make many shareable utility functions in Spin2 so that they can be used with PNut as well.

  • @evanh said:

    @"David Betz" said:
    On another note, how many people here are using C on the P2? From looking at the posts it seems most people are using Spin, PASM, or Basic.

    I both prefer and use C myself. But since Flexspin has not problem integrating multiple languages in one build, I make many shareable utility functions in Spin2 so that they can be used with PNut as well.

    It is very useful that FlexSpin allows code from multiple languages to be linked together into a single program. Eric has given us an invaluable tool.

  • pik33pik33 Posts: 2,352

    It is very useful that FlexSpin allows code from multiple languages to be linked together into a single program. Eric has given us an invaluable tool.

    There is a lot of C code here and there. The example: while my player is written in Basic, the mp3 decoder is in C, as there was the Adafruit mp3 decoder and then several Eric's updates allowed it to run on P2 without need to rewrite several thousands lines of code to Spin or anything else.

  • I've made the warnings about array indices out of range be controlled by a flag (-Warray-index) which is on by default, but like all warnings may be disabled either globally on the command line or on a per-function basis via function attributes. Also, the warning does not happen if the array index is not an explicit constant, so something like:

       i=2; p->arr[i] = 0;
    

    will never generate a warning, even if the array is only declared with one element.

  • Greg LaPollaGreg LaPolla Posts: 319
    edited 2023-11-06 20:30

    @ersmith

    Just grabbed the latest git repo and I get

    too many files specified on command line

    This is using Compile & Run on a mac.

    This is happening on the loadp2 command

  • @"Greg LaPolla" said:
    @ersmith

    Just grabbed the latest git repo and I get

    too many files specified on command line

    This is using Compile & Run on a mac.

    This is happening on the loadp2 command

    I'm not able to reproduce this at all. When you say "the latest git repo" do you mean that you built from source, or that you downloaded the latest binary release? What does the loadp2 command line look like (it's printed in the Compiler Output pane at the bottom of the window). Does it happen with all programs you try to run, or just some of them? If you use the Commands > Configure Commands... menu item to switch back to P2 defaults, does it still happen?

  • I deleted ~/flexprop.config.2 and restarted the app and works now. I had reset the default settings and it still continued to give that error. but after removing the config file it seems ok.

  • RaymanRayman Posts: 14,033
    edited 2023-11-10 22:48

    Resurrecting some old C code with inline assembly...

    Seems asm{} blocks used to need an "end" at the end, but now gives error:
    i2c.h:250: error: conditional assembly endif without if

    Also, not sure if I can ignore this or not:
    i2c.h:230: warning: REP in inline assembly may interfere with optimization

  • evanhevanh Posts: 15,278
    edited 2023-11-11 00:51

    @Rayman said:
    Also, not sure if I can ignore this or not:
    i2c.h:230: warning: REP in inline assembly may interfere with optimization

    Multiple solutions for that:

    • declare it as non-optimising with either const or volatile modifier. eg:
        __asm const {    // non-optimised, inlined
            nop
        }
    
        __asm volatile {    // non-optimised, Fcached
            nop
        }
    
    • declare the container function as cogexec with __attribute__((cog)) or __attribute__((lut)) modifier. eg:
    void  funcname( void ) __attribute__((cog))
    {
        __asm {
            nop
        }
    }
    
    • or combinations of those.

    PS: Be aware that setting the function to cogexec permanently loads that function into the cog. Thereby reducing free cog space.

  • Wuerfel_21Wuerfel_21 Posts: 4,601
    edited 2023-11-11 01:38

    Loading it into cog or lut won't help with that one. The REP issue is because the optimizer can't see the loop properly when you manually write it out like that. When it generates REPs itself, it inserts a dummy instruction at the bottom so it can work with it.

  • evanhevanh Posts: 15,278

    Huh, I thought I'd already tested that. Must of had them combined at the time.

  • You can of course write a normal DJNZ loop and have the optimizer convert it to REP.

  • evanhevanh Posts: 15,278
    edited 2023-11-11 02:47

    I'm happy with those directives. Nearly all my Pasm is timing crafted. Though I did use SETQ+QDIV for quick 64-bit division the other day. I left that as a plain __asm {} for the optimiser to handle as it saw fit. It was tacked on after a tight loop that used two 32-bit registers to accumulate many samples into 64-bits.

  • @Rayman said:
    Resurrecting some old C code with inline assembly...

    Seems asm{} blocks used to need an "end" at the end, but now gives error:
    i2c.h:250: error: conditional assembly endif without if

    I don't think end was ever needed in C asm blocks (they are delimited with { and }). I guess that end was tolerated and/or ignored in such blocks at one time, but it is used now as the marker for the end of conditional assembly, so that's no longer possible.

    Also, not sure if I can ignore this or not:
    i2c.h:230: warning: REP in inline assembly may interfere with optimization

    It depends on what you're trying to do. In general it's probably better to write the loops in C with the inline assembly inside the loop: the less inline assembly, the better. If you need exact timing for something, you should mark the code as asm const to tell the optimizer to leave it alone.

  • @Rayman said:

    >

    Also, not sure if I can ignore this or not:
    i2c.h:230: warning: REP in inline assembly may interfere with optimization

    @Rayman Can you tell me what I2C library you're using? I'm currently trying to get an INA219 IMU sensor to work with Arduino code, and getting I2C to work has been much harder than I thought it would be.

  • RaymanRayman Posts: 14,033
    edited 2023-11-17 20:39

    I think this is the latest (attached).

    If you want to automatically generate code to use an earlier version you can try P2C:
    https://forums.parallax.com/discussion/173312/

    This does remind me that I want to, one day, create a "Wire" named version that can be a P2 drop in for Arduino code...

    h
    h
    15K
    I2C.h 14.9K
  • Thanks @Rayman

  • @ersmith

    It looks like that aligning code is not working at least since version 6.0.x. Tried 6.0.5 to actual version.
    The words alignl and alignw are treated as a symbol instead of a keyword. This comes only to your attention if one used these instructions multiple times in the same file. Then you get the following error message from second occurrence on.

    Changing hub value for symbol alignl

    At least the last working version I use is 5.0.4.

  • @Kaio said:
    @ersmith

    It looks like that aligning code is not working at least since version 6.0.x. Tried 6.0.5 to actual version.
    The words alignl and alignw are treated as a symbol instead of a keyword. This comes only to your attention if one used these instructions multiple times in the same file. Then you get the following error message from second occurrence on.

    Changing hub value for symbol alignl

    At least the last working version I use is 5.0.4.

    alignl is a Spin2 keyword and is not recognized in Spin1. Make sure the file you're using has a .spin2 extension if you want to use Spin2 features (whether on P1 or P2).

    Really old versions of the compiler used to treat both languages almost the same and probably accepted alignl in Spin1 code, but as the Spin2 language developed and diverged from Spin1 this became impossible, and so the compiler is stricter now about the file extension.

  • @ersmith said:
    alignl is a Spin2 keyword and is not recognized in Spin1. Make sure the file you're using has a .spin2 extension if you want to use Spin2 features (whether on P1 or P2).

    Thanks, you are right with .spin2 extension. But I wondering why this problem occurs if one use the -2 option on flexspin. I would expect that it compiles using P2 specification regardless of the file extension.

  • @Kaio said:

    @ersmith said:
    alignl is a Spin2 keyword and is not recognized in Spin1. Make sure the file you're using has a .spin2 extension if you want to use Spin2 features (whether on P1 or P2).

    Thanks, you are right with .spin2 extension. But I wondering why this problem occurs if one use the -2 option on flexspin. I would expect that it compiles using P2 specification regardless of the file extension.

    Spin1 and Spin2 are different (but related) languages, much like C and C++. From FlexProp's perspective this has nothing to do with which processor you are compiling for. You can use FlexProp to compile Spin1 for P2 or Spin2 for P1 (as long as the programs do not use any hardware specific features, of course).

  • RaymanRayman Posts: 14,033

    That is a cool feature of FlexProp where you can do Spin1 on P2 and Spin2 on P1, if you want.

    Chip really listened to Spin2 feature requests and delivered on a language that is much better, IMHO.
    So, if I were to do something on P1 again, I might be very tempted to do it with FlexProp and Spin2.
    OTOH, there is a lot of existing Spin1 code for P1, so might not work the best....

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