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Forum Index : Microcontroller and PC projects : Address a Bit in a Byte

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atmega8

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Joined: 19/11/2013
Location: Germany
Posts: 724

Posted: 10:03am 08 Sep 2016

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Hi,

Is this possible in mmbasic?

DIM A as Byte

Bit1 = Byte.1
Bit2 = Byte.2

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.
.
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Edited by atmega8 2016-09-09

JohnS
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Joined: 18/11/2011
Location: United Kingdom
Posts: 4036

Posted: 10:40am 08 Sep 2016

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Not like that, but you can do things like
bitN = value AND (1 << N)

The parens aren't needed but I would say more readable.

(not tested, sorry)

Or simply
bit0 (bit1 if you prefer that terminology) = value AND 1
bit1 (bit2 if you prefer that terminology) = value AND 2
bit2 (bit3 if you prefer that terminology) = value AND 4

hmm, if you want them each to be 0 or 1 then you need more like
bitN = (value >> N) AND 1

JohnEdited by JohnS 2016-09-09

CaptainBoing

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Joined: 07/09/2016
Location: United Kingdom
Posts: 2170

Posted: 12:53am 22 Sep 2016

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Some code I use a lot... any use?

FUNCTION BitSet(value,bit)
BitSet=value or (2^bit)
end function

FUNCTION BitRes(value,bit)
BitRes=(value or (2^bit)) xor (2^bit)
end function

FUNCTION BitTest(value,bit)
BitTest=sgn(value and (2^bit))
end function

you then use it like:
flags=BitSet(flags,0) to set a bit in a variable
...
flags=BitRes(flags,0) to clear a bit in a variable
...
x=BitTest(flags,0) to test a bit in a variable

etc...

all the best

h

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