Invert byte / flip bits using single operation

[benoitstjean]

Hi guys,

Not sure what I'm doing wrong here but I cannot figure-out what the problem is.... let's say I have this byte:

unsigned int16 Data_ID = 0xFF02; (1111 1111 0000 0010)

I now want to invert the bits. I thought a simple Data_ID != Data_ID; would convert the value to 0x00FD (0000 0000 1111 1101). Didn't work.

Then I tried Data_ID ~= Data_ID and that also has no effect.

In both cases, the value is always 0.

Am I missing something here?

Thanks,

Ben

[PCM programmer]

Do this:

[benoitstjean]

Ah! I had tried it but I think I had screwed-up something else! Works now! Thanks!

Ben

[Ttelmah]

As a comment here, it is possibly worthwhile looking at what the operators
'do', as to why ! did not work.

! -> logical negate. Makes something that tests as true return a false, and
something that tests as false return true. So won't invert the bits, but the
logical 'result'.
~ -> bitwise not. Inverts every bit in the number. For a 16bit number, same as
^=0xFFFF
This "xor's" each bit with the corresponding bit in the second value. Since
each is 1, this does the same thing as the ~