Skip navigation
Up to Discussions in ToneCore Development Kit
1594 Views 4 Replies Latest reply: Feb 15, 2010 10:28 AM by RedPandaCurt RSS
audioartillery Just Startin'
audioartillery
80 posts since
Apr 18, 2008
Currently Being Moderated

Feb 14, 2010 9:17 PM

How to define a lookup table?

I've got this lookup table I'm generating.  I can't figure out how to put it in memory though.  I am trying something like this:

 

            org y:$000

 

    BUFFER  M,256
            dc #$000000 ; word 000
            dc #$00C90F ; word 001

            ...

    ENDBUF

 

But the assembler is unhappy ("ERROR --- Symbols must start with alphabetic character (Operand field)" on the dc lines).  What's the right way to define a block of memory?

 

Thanks.

  • clangen Just Startin'
    clangen
    25 posts since
    Jul 8, 2009
    Currently Being Moderated
    Feb 14, 2010 10:43 PM (in response to audioartillery)
    Re: How to define a lookup table?

    Hi audioatillery,

     

    a while ago we discussed the problem defining constand blocks in x: and y: memory spaces. Assembler directive DC (Define Constant) does not work, see:

     

    http://line6.com/community/thread/4643 .

     

    The problem is that during the bootload process only the program memory p: can be load. Please use the method I recommend here to fill the memory with constants during runtime.

     

    The assembler error was generated since you declared the constant after using a tap, not left aligned as it should be. Since that the dc assembly directive is interpreted as an unkown instruction.

     

    I know that filling the memory during runtime by using core instruction yields a lengthy program that doesn't fit into the p: memory space below $200 wery soon. For the moment I'm figuring out the problem described in thread http://line6.com/community/message/117946#117946 for that reason.

     

    Best regards

     

    Christian

  • RedPandaCurt Just Startin'
    RedPandaCurt
    23 posts since
    Oct 30, 2009
    Currently Being Moderated
    Feb 15, 2010 5:49 AM (in response to audioartillery)
    Re: How to define a lookup table?

    This is similar to the thread Christian pointed to above, but what I do is put the DC's in a new P data section, below the main (p:$4E) section.  I add a DS directive in the X or Y data sections and then use a loop to copy the constants over.  That uses less code space than coding individual moves with constants if the number of constants is large.

     

    X or Y data:

     

    Foo ds 4

     

    Initialization section:

     

         move #FOO_CONSTS_0,r0

         move #Foo,r1

         do #4,_init_foo_done

         move p:(r0)+,x0

         nop

         move x0,x:(r1)+

    _init_foo_done

     

    Constant P data section:

     

    section P_DATA_MEMORY global


    org p:


    FOO_CONSTS_0    dc      $056358

    FOO_CONSTS_1    dc      $352324

    FOO_CONSTS_2    dc      $fe83a3

    FOO_CONSTS_3    dc      $98bc23


    endsec

        
         -curt

    • audioartillery Just Startin'
      audioartillery
      80 posts since
      Apr 18, 2008
      Currently Being Moderated
      Feb 15, 2010 10:19 AM (in response to RedPandaCurt)
      Re: How to define a lookup table?

      Thanks guys.  My actual error was writing "dc #$abcdef" instead of "dc $abcdef" (the # sign).  But it was good you guys pointed out the inability to DC in data memory.  I wonder if you muck with the CPU loader if you could fix that.  It clearly is able to initialize the X memory (debug value writes, for example).

       

      RedPanda, why copy the data from program to data memory?  So you don't stall the CPU fetching both instructions and data from program memory?

More Like This

  • Retrieving data ...

Bookmarked By (0)

Legend

  • Correct Answers - 5 points
  • Helpful Answers - 3 points