Array of constant on BS2?

MCA · 2014-05-16 13:35

I would like to make an array of constants on my BS2. The reason is I wish to save ram - don't need a variable, but I do want to be able to loop the values of the array. Is it possible to declare an array of constants in Pbasic? From what I can tell it is not.

If not, is there another way to do this smoothly?

BR/ MCA

Sapphire · 2014-05-16 14:06

You could put them in a DATA statement and retrieve them with a READ statement

DATA 10,20,30,40,50,60,70,80

X VAR BYTE
Y VAR BYTE

FOR X = 0 TO 7
  READ X,Y
  DEBUG DEC X, TAB, DEC Y, CR
NEXT

The DEBUG is just to show you how the READ works.

You probably wouldn't read them in a loop in your program; instead just READ the one you want when you need it.

READ 5,Y

MCA · 2014-05-19 06:11

Thanks, that might be useful!

BR / MCA

Zoot · 2014-05-23 14:14

Here is a pseudo "constant" array that will take up code space but no ram.

' {$STAMP BS2}
' {$PBASIC 2.5}



const1 CON 1
const2 CON 2
const3 CON 3
const4 CON 4
' ... etc

tmpN1 VAR NIB ' work nib
tmpB1 VAR BYTE ' work variable; you should always have at least one!
tmpW1 VAR WORD ' ditto


' pass the index value of the constant you want (say, 0-3) and get the value back in tmpW1
Get_Const_By_Index:
    LOOKUP tmpN1, [ const1, const2, const2, const4 ], tmpW1
    RETURN

' get the constant whose value is just greater than the passed "test" value
' presumes constants are arranged in ascending order
Get_Const_By_LT_Val:
    LOOKDOWN tmpN1, <[ const1, const2, const2, const4 ], tmpN1
    GOSUB Get_Const_By_Index
    RETURN

' etc

Array of constant on BS2?

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