Modifying Dat in program.

Clock Loop

Can a dat entry, like such.

DAT

FourBytes                byte    $00, $FF, $00, $0F  

Be modified in a running program?

Say I wanted to modify the first byte in FourBytes.

From value $00 to value $FF. How would I do this?

I tried looking at the prop manual, and didn't see anything there. I tried a forum search...

Rayman

There are many ways to do it... One is:

byte[noparse][[/noparse]@FourBytes]:=$FF

You can also just do (since you just want the first byte):

FourBytes:=$FF

If you want to get at·the nth byte (n=0..3), you can do:

FourBytes[noparse][[/noparse]n]:=$FF

or,

byte[noparse][[/noparse]@FourBytes][noparse][[/noparse]n]:=$FF

or,

byte[noparse][[/noparse]@FourBytes+n]:=$FF

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My Prop Info&Apps: ·http://www.rayslogic.com/propeller/propeller.htm

Clock Loop

So DAT is just a different way of declaring a variable?

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Meh. Nothing here, move along.

heater

Yes and no.

If you create many instances of an object in your program they will all have their own private VAR space in memory but they will all share the same DAT space.

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For me, the past is not over yet.

Clock Loop

I get it now.

If I ran 2 copys of the same object(different names), their DAT statements would be accessable to eachother, but their variables stay local to that object?

Thats why one doesn't need to be careful with variable names, but im assuming with DAT you must be careful with names because if two objects have a Dat with the same name problems happen?

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Meh. Nothing here, move along.

BradC

BPM said...
I get it now.

If I ran 2 copys of the same object(different names), their DAT statements would be accessable to eachother, but their variables stay local to that object?

Thats why one doesn't need to be careful with variable names, but im assuming with DAT you must be careful with names because if two objects have a Dat with the same name problems happen?

No all symbol names (DAT/VAR/PUB/PRI) are local to the object. There are no collisions between names across different objects.

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"VOOM"?!? Mate, this bird wouldn't "voom" if you put four million volts through it! 'E's bleedin' demised!

Clock Loop

I have another question along the same lines.

Lets say I launched an object to read a value and told it to store that value at the address of INFO.

CON

  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

OBJ
  modinfo: "modinfo"
  serial : "fullDuplexSerialPlus"

PUB start

modinfo.start(@info)

serial.start(03, 02, 0, 57600)
serial.hex(info[noparse][[/noparse]0],2)
serial.str(string(9)) 'TAB
serial.hex(info,2)
serial.str(string(9)) 'TAB
waitcnt(400_000 + cnt)  ' let serial finish printing before stopping.
serial.stop

DAT

info                byte    $00, $FF

Now the modinfo.spin code.

CON
  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000


PUB start (infopointer) | moreinfo

moreinfo := $FF

infopointer[noparse][[/noparse]0]:= moreinfo   

This part
infopointer[noparse][[/noparse]0]:= moreinfo
is not working.
Or something.
Because when i run the program, it still prints

$00              $FF

Phil Pilgrim (PhiPi)

You're passing an address via infopointer. So instead of

infopointer[noparse][[/noparse]0]:= moreinfo 

use

byte[noparse][[/noparse]infopointer] := moreinfo

infopointer is just a local variable that receives the value @info. Changing a local variable by assigning to it has no effect outside the method to which it's local.

-Phil

Post Edited (Phil Pilgrim (PhiPi)) : 6/6/2009 10:45:15 PM GMT

Clock Loop

so not only do I have to tell it where, I have to tell it how much info to pass?

well what if I wanted to pass the n'th byte?

byte[noparse][[/noparse]infopointer [noparse][[/noparse]n] ] := moreinfo    '?

Well this doesn't work, ...


I just read the prop manual on

BYTE

That answered my questions.

Thank you all.

byte[noparse][[/noparse]infopointer][noparse][[/noparse]n] := moreinfo   

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** P O O F **

Post Edited (BPM) : 6/6/2009 11:17:48 PM GMT

mpark

That manual is just chock full of useful information.