switching a 0 to a 1 and so on...

Reach

In Spin

What is the simplest way to flip a bit 0 ot a 1 in a variable long without changing the other bits. As well as switch a 1 to a 0.

Example

Temp := 0000,0000,0000,0000,0000,0000,0000,0000

Now I want to turn bit 3 from a 0 to a 1

Temp := 0000,0000,0000,0000,0000,0000,0000,0100

Ron Czapala

http://forums.parallax.com/showthread.php/145995-Setting-a-single-bit-in-Spin?p=1163846&viewfull=1#post1163846

Reach

Can someone run this and tell me if element is 511

CON
  _clkmode   = xtal1 + pll16x                           
  _xinfreq   = 5_000_000


VAR


  long  element   
  long  numb[9]


Pub main | temp, v


            '%0000_0000_0000_0000_0000_0001_1111_1111
  numb[0] := %0000_0000_0000_0000_0000_0000_0000_0001 
  numb[1] := %0000_0000_0000_0000_0000_0001_0000_0000 
  numb[2] := %0000_0000_0000_0000_0000_0000_0000_0100
  numb[3] := %0000_0000_0000_0000_0000_0000_1000_0000
  numb[4] := %0000_0000_0000_0000_0000_0000_0000_1000
  numb[5] := %0000_0000_0000_0000_0000_0000_0000_0010
  numb[6] := %0000_0000_0000_0000_0000_0000_0001_0000 
  numb[7] := %0000_0000_0000_0000_0000_0000_0100_0000 
  numb[8] := %0000_0000_0000_0000_0000_0000_0010_0000 
  
  V:= 0
  element := %0000_0000_0000_0000_0000_0000_0000_0000
  
  Repeat 9  
    Case numb[v]
      1:  temp := %0000_0000_0000_0000_0000_0000_0000_0001
      2:  temp := %0000_0000_0000_0000_0000_0000_0000_0010
      3:  temp := %0000_0000_0000_0000_0000_0000_0000_0100
      4:  temp := %0000_0000_0000_0000_0000_0000_0000_1000
      5:  temp := %0000_0000_0000_0000_0000_0000_0001_0000
      6:  temp := %0000_0000_0000_0000_0000_0000_0010_0000
      7:  temp := %0000_0000_0000_0000_0000_0000_0100_0000
      8:  temp := %0000_0000_0000_0000_0000_0000_1000_0000
      9:  temp := %0000_0000_0000_0000_0000_0001_0000_0000
      0:  temp := %0000_0000_0000_0000_0000_0000_0000_0000
      
    v :=   v + 1
    element := element ^ temp

JonnyMac

There's an easier way:

pub flip_bit(value, bit)

  if ((bit => 0) and (bit =< 31))
    value ^= 1 << bit

  return value

Reach

Thanks JonnyMac and Ron I needed that. :thumb:

I dont have my propeller kits - power on the sail boat is low and so I am trying to do a little something with that code up there. I needed someone to run that code for me but I can wait for sun to charge my battery's. In fact my laptop is almost dead.