Why does DataLoc++ work one way but not another

dbpage

Why does

DataLoc := 0
repeat i from 0 to 10              
  long[VarData][DataLoc] := DataLoc++

Result in

0	0	1	2	3	4	5	6	7	8	9 ...

and

DataLoc := 0
repeat i from 0 to 10              
  long[VarData][DataLoc] := DataLoc
  DataLoc++                        

Result in

0	1	2	3	4	5	6	7	8	9     10 ...

Electrodude

I'm assuming you understand why your second snippet behaves how it does.

Your first snippet behaves how it does because the right hand side of an assignment operator in Spin is evaluated before the left hand side. The DataLoc in "long[VarData][DataLoc]" is already incremented by the time the address to store the value at is calculated.

In other words, "long[x] := y" expects x to be above y on the stack. Therefore, y has to be calculated first. The incrementation of DataLoc happens when the y in my example is evaluated, and it is used again after that when the x in my example is evaluated.

dbpage

That explains why

DataLoc := 0
repeat i from 0 to 10              
  long[VarData][DataLoc++] := DataLoc

works the same as the second snipet.

Thanks!