more than 15 parameters to pass to a cog?

Zap-o · 2009-08-25 18:51

I need to pass more than 15 parameters to a cog. Can this be done?

Cog.start (_ff, _Tf, _X0, _X1, _Y0, _Y1, _Vr2, _aR1, _aR2, _Pb1, _Pb2, _Pb3, _Ab1, _Ab2, _Ab3,_kb1, _kb2, _kb3, _max, _min, _all)

jazzed · 2009-08-25 18:57

Don't know if there's a constraint on th number of parameters, but you could try this.

pub start(_ff, _Tf, _X0, _X1, _Y0, _Y1, _Vr2, _aR1, _aR2, _Pb1, _Pb2, _Pb3, _Ab1, _Ab2, _Ab3,_kb1, _kb2, _kb3, _max, _min, _all)
  cognew(@pasm, @_ff)

dat
pasm org 0
' ...

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--Steve

Propeller Tools

Agent420 · 2009-08-25 18:59

I'm no Propeller wizard, but the first thing that comes to mind is to look at how the video examples pass their parameters.· They store the data in the DAT section and pass the address and count.

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Mike Green · 2009-08-25 19:18

Usually how this is done is that you have a series of long variables declared in order, then pass the address of the first variable like this:

VAR
   long _ff, _Tf, _X0, _X1, _Y0, _Y1, _Vr2, _aR1, _aR2, _Pb1, _Pb2, _Pb3, _Ab1, _Ab2, _Ab3, _kb1
   long _kb2, _kb3, _max, _min, _all

PUB mainMethod
   cog.start(@_ff)

PUB start(address)
   cognew(@pasm,address)

DAT
             org     0
pasm:    mov   temp,PAR          ' Hub address of parameters
             movd move,#table      ' Cog address of copy of parameters
             mov   count,#21         ' Number of parameters
move:    rdlong 0-0,temp          ' Read one parameter
             add    move,destIncr   ' Increment destination address
             add    temp,#4           ' Increment source address
             djnz   count,#move     ' Repeat for all parameters
' Here we continue with other code
...
destIncr long   $200                 ' Add one to destination field
count     res     1
temp      res    1
table      res    21

You can also copy the parameters in the Spin start method like:

PUB start(address)
   longmove(@table,address,21)
   cognew(@pasm,0)

DAT
             org    0
' Here we continue with other code
...
table      long   0[noparse][[/noparse]21]                ' Allocate space for a copy of all the parameters
' You can't use RES here because the table has to occupy hub space (so it can be copied)

Post Edited (Mike Green) : 8/25/2009 7:24:42 PM GMT

jazzed · 2009-08-25 19:25

Agent420 offers good advice.
Either way you go, it will be painful though ... unless your interface parameters lose weight [noparse]:)[/noparse]
You could use a generic buffer instead and provide methods to do get/set on the parameters.

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--Steve

Propeller Tools

Zap-o · 2009-08-25 19:29

Thanks I got it working.

BradC · 2009-08-26 01:23

jazzed said...
Don't know if there's a constraint on th number of parameters, but you could try this.
pub start(_ff, _Tf, _X0, _X1, _Y0, _Y1, _Vr2, _aR1, _aR2, _Pb1, _Pb2, _Pb3, _Ab1, _Ab2, _Ab3,_kb1, _kb2, _kb3, _max, _min, _all)
  cognew(@pasm, @_ff)

Bad, bad, bad, no, no, no!
You are passing the long address of a set of parameters on the stack. By the time the cog has loaded the spin routine will have returned and possibly damaged the stack contents. Don't do this.

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lt's not particularly silly, is it?

Phil Pilgrim (PhiPi) · 2009-08-26 01:35

Good catch, Brad! To eliminate this problem, one could either program a delay before returning or wait for the newly-started cog to change one of the parameters to indicate, "I got it!" In any event, the new cog needs to copy these values to its own cog memory posthaste, since they are transient.

But I'd be much more inclined just to do a longmove from @_ff to a parallel area in the DAT section before doing the cognew.

-Phil

Post Edited (Phil Pilgrim (PhiPi)) : 8/26/2009 1:40:15 AM GMT

jazzed · 2009-08-26 01:50

Oops you're right of course

I usually add a delay after cognew or poll for the cog to finish in my code to make sure the cog loads before i try to use it. For example, even doing the RightThing(tm) as in FullDuplexSerial and not waiting for it to load before calling fd.str(string("Hello")) pretty much guarantees output failure. Shrug shoulders [noparse]:)[/noparse]

So, Is Python really named after Monty Python?

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--Steve

Propeller Tools

more than 15 parameters to pass to a cog?

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