How to set / reset bit in the variable? (Spin)

Alarus

How to set / reset any bit in the variable?
And how to test a bit in a variable?

Regards Alarus

kuroneko

v |=  |< bit                  ' set
  v ^=  |< bit                  ' toggle
  v &= !|< bit                  ' reset

  if v & |< bit                 ' test
    ' do something

Alarus

kuroneko wrote: »

v |=  |< bit                  ' set
  v ^=  |< bit                  ' toggle
  v &= !|< bit                  ' reset

  if v & |< bit                 ' test
    ' do something

Thank you!
I wanted to use such construction:

v |=  $00000001 <- bit                      ' set
v ^=  $00000001 <- bit                      ' toggle
v &= $FFFFFFFE <- bit                       ' reset

but your beautiful.

JonnyMac

I have these methods in my standard template:

pub rd_bit(target, pos)

'' returns bit value (0..1) of target.pos

  if ((pos => 0) and (pos =< 31))
    return (target >> pos) & 1
  else
    return 0


pub wr_bit(target, pos, value)

'' writes value.0 to target.pos

  if (value & 1)
    return target | (1 << pos)
  else
    return target & !(1 << pos)

JLocke

What's the chances of getting you to post your standard template somewhere? I try to collect the pieces as I see you post these handy routines, but it would be great to get them all in a collection.
<voice of Roger Rabbit> Pleeeease, Jonny? </Rabbit off>

JonnyMac

I'm not sure how useful this will be to you or anyone else, but you're certainly welcome to it.

Rayman

This gets asked a lot...

My personal favorite way is to use the normally unused DIRB, INB, or OUTB registers...
Just like with INA, you can test and set bits in any of these...

Alarus

Which of these methods is the fastest?

Thanks for the idea Rayman.

JonnyMac

The good news is that you can use the Propeller to determine how long a snippet of code runs. I do timing tests frequently enough that I made a template just for that purpose.