How to do absolute value in integer math for BS1

tact1cal

Hi all,

Is there a simple round-about way to subtract (2)· 16-bit numbers and get the absolute value difference? I need this for the·BS1.

Appreciate any simple solutions...

Thanks,

-Guy

Jon Williams

Since there's no ABS function in PBASIC 1 you'll have to do a bit more work:

Get_Abs:
· IF aVal < bVal THEN B_Bigger
· result = aVal - bVal
· GOTO Abs_Done

B_Bigger:
· result = bVal - aVal

Abs_Done:


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Jon Williams
Applications Engineer, Parallax

tact1cal

Thanks, Jon

I had thought about this solution....thanks for simplifying it!

R/

-Guy

foobert

or do the subtraction, test the high order bit of the result and, if it's set, negate the result.

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"i want to lead a disipate existence play scratchy records and enjoy my declinw" - iggy pop, i need more

Jon Williams

That would work, but to keep things simple you'd have to force the result into W0 as that's the only BS1 word that allows direct bit access.

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Jon Williams
Applications Engineer, Parallax