Type Casting/Conversion

[Dizzy]

Hello again,

I'm modifying some code where I need to store the value from a byte into a long. I suppose I could do this with shifts and the like but is there a simpler way? I've tried for instance: LONG[v126] := BYTE[packet1]

I can't tell if that works or not.. according to my test program it doesn't haha. Is there an easier cast or a simple trick that anyone knows who has run into this?

Thanks,
D.

[Mike Green]

If "v126" is a LONG and "packet1" is a BYTE, you just need to write "v126 := packet1". When the Spin interpreter fetches a value, it's converted to a 32-bit value (to store on the stack). What you wrote, "LONG[v126] := BYTE[packet1]", means take the byte value at the address contained in "packet1", extend it to 32 bits and store it in the long variable at the address contained in "v126".

[Paul Baker]

If you are using signed numbers (-128 to 127) then be sure to sign extend by using ~BYTE[packet1].

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Paul Baker (mailto:pbaker@parallax.com)
Propeller Applications Engineer
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Parallax, Inc. (http://www.parallax.com)