question on LSBs

[+atari2600land]

I've read the section in the help file about variables and for some reason I still can't use c{0}. For example, if I put

 

if c{0}=0 then...(more code)

 

a message will come up saying "Error: unknown keyword=0."

 

Sometimes I use a variable different for what the dim at the beginning says, but if I can get c{0} - c{7} to work, I can free up more variables! I used c because it's a constant all throughout my code (and it's always either 0 or 1.)

 

help!

gosub120806a.bas

[SeaGtGruff]

I've read the section in the help file about variables and for some reason I still can't use c{0}. For example, if I put

 

if c{0}=0 then...(more code)

 

a message will come up saying "Error: unknown keyword=0."

 

Sometimes I use a variable different for what the dim at the beginning says, but if I can get c{0} - c{7} to work, I can free up more variables! I used c because it's a constant all throughout my code (and it's always either 0 or 1.)

 

help!

The bit operations don't work that way in the if statement. To *check* a bit, you use

 

  if c{0} then ...

to see if the bit is on (i.e., equal to 1), and you use

 

  if !c{0} then ...

to see if the bit is off (i.e., equal to 0).

 

On the other hand, if you want to *set* a bit to 1 or 0, you use

 

  c{0} = 1 : rem * set the bit to 1
  c{0} = 0 : rem * set the bit to 0

Michael

[+atari2600land]

Thanks for clearing that up for me.

[SeaGtGruff]

Thanks for clearing that up for me.

You're welcome. I had the same problem when I tried to use the bit operations in if statements. In fact, don't some of the examples in the documentation/help guides show it being used that way (the wrong way)? I might be mistaken about that, though.

 

Michael