DIV32 Understanding

[Normnet]

Yes. The example is where I got the idea to use variables instead of constants. But my question is WHY can't constants be used.

You are asking the inner workings of the compiler probably in assembly.
Command DIV32 is unique as it is directly linked to its preceding line as part of the command.

Norm

[enauman]

Maybe it should be called out in the command description. It's a trivial point. I was just curious.

[Darrel Taylor]

DIV32 requires certain system variables to have a 32-bit value in them.
They are initialized by a multiplication operation with at least 1 word (the second value can be a constant).
Then a library routine can be executed to do the multiplication.

Part of the optimization of PBP is called "Constant Folding"
If both values in the multiplication are constants ... the compiler multiplies them at "Compile-Time" and uses a single value (a constant).
No multiplication is performed at run-time, and the system variables are never loaded with the 32-bit value.

I've talked about DIV32 and the System vars it uses a few years ago ... http://www.picbasic.co.uk/forum/showthread.php?t=1942

[enauman]

Thanks for the explanation Darrel. Exactly what I was looking for.

[Acetronics2]

Buuuuut ...

The most charming girl this forum ever saw ( of course Melanie ! ) gave us long time ago the way to load those registers with a macro ... if my memory still works fine. AND ... I might still have a print of that ...

Here's Darrel's edition : http://www.picbasic.co.uk/forum/showthread.php?t=1942 ...

Alain