Conversion of Byte to 8 Bits

John Ritz

What's the easiest and quickest way to convert from a byte variable to its 8 bits in a BS2?

For example, I have the following:

MyByte VAR BYTE
MyBit0 VAR BIT
MyBit1 VAR BIT
MyBit2 VAR BIT
MyBit3 VAR BIT
MyBit4 VAR BIT
MyBit5 VAR BIT
MyBit6 VAR BIT
MyBit7 VAR BIT

I want to be able to set MyBit0 through MyBit7 to equal bits 0 - 7 respectively of MyByte.

Thanks!

Newzed

You write"



thing· var· byte
thing0 var thing.bit0
thing1 var thing.bit1
thing2 var thing.bit2

and so

Now you have 8 variables corresponding to the 8 bits of thing byte.· You can now assign values to those bit variables.





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Sid Weaver
Do you have a Stamp Tester?

http://hometown.aol.com/newzed/index.html
·

Jon Williams

All variables, except bits, have bit modifiers. Sid showed how you can alias them above; you can also use them directly in code.

myByte = 0
myByte.BIT3 = 1 ' myByte now holds 8

You can also index through the bits of a variable.

FOR idx = 0 TO 7
· myByte.LOWBIT(idx) = 1
NEXT

(Silly example, I know, I simply wanted to demonstrate the use of the LOWBIT() modifier)

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

John Ritz

Thanks! That is nice!
So if I want to get bits 0 - 7 of a byte variable I can just do this:

myByte VAR BYTE
idx VAR BYTE
 
myByte = 85
 
for idx = 0 to 7
   if myByte.LOWBIT(idx) = 1 then
      'do something here...
   endif
next

Just to confirm, in a byte variable, you would always use LOWBIT, but in a word variable, you could use LOWBIT and HIGHBIT, correct?

I could also do this then per Newzed:

myByte VAR BYTE
idx VAR BYTE
 
myByte = 85
 
if myByte.bit0 = 1 then
   'do something here...
endif
 
if myByte.bit1 = 1 then
   'do something here...
end if

If I was concerned with the code overhead time of LOWBIT (which I am assuming is higher than .bitx)

If I am correct here, this should suit my program nicely!

Thanks...John

Jon Williams

No, you would always use LOWBIT (there is a HIGHBIT modifier, but it can be confusing) -- with a Word variable you would have an index value of 0 to 15.

Yes, using the LOWBIT modifier adds some overhead, but it also adds flexibility that you don't get with straight aliasing.

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA