Logical operators bugged? (*solved*)

[britlion]

Code:

dim i as uByte

FUNCTION CONTRAST (colour as uByte) as uByte
    IF colour <=3 then return 7: END IF
    return 0
END FUNCTION

FOR i = 0 to 7
PRINT "SENT ";i;" GOT ";CONTRAST(i)
NEXT i

This comes back with:

Code:

Sent 0 Got 0     Should be     Sent 0 got 7
Sent 1 Got 0     Should be     Sent 1 got 7
Sent 2 Got 0     Should be     Sent 2 got 7
Sent 3 Got 7     Should be     Sent 3 got 7
Sent 4 Got 7     Should be     Sent 4 got 0
Sent 5 Got 7     Should be     Sent 5 got 0
Sent 6 Got 7     Should be     Sent 6 got 0
Sent 7 Got 7     Should be     Sent 7 got 0

Okay... with "<=3" at least 3 should be the same as 2...yes? And why do 0,1,2 get a return of 0 when they should get a return of 7?

Things get weirder:

Assuming that it was some weird return issue, I decided to return a variable instead:

Code:

dim i as uByte

FUNCTION CONTRAST (colour as uByte) as uByte
    DIM rt as uByte
    IF colour <=3 then rt=7: END IF
    IF colour >=4 then rt=0: END IF    
    return rt
END FUNCTION

FOR i = 0 to 7
PRINT "SENT ";i;" GOT ";CONTRAST(i)
NEXT i

This gave me:

This comes back with:

Code:

Sent 0 Got 0
Sent 1 Got 0
Sent 2 Got 0
Sent 3 Got 7
Sent 4 Got 0
Sent 5 Got 0
Sent 6 Got 0
Sent 7 Got 0

I mean. SRSLY? My opinion of what that code does is clearly disagreeing with zxb's version..

Perhaps it's because we didn't initialise rt?

Code:

dim i as uByte

FUNCTION CONTRAST (colour as uByte) as uByte
    DIM rt as uByte
    rt=9
    IF colour <=3 then rt=7: END IF
    IF colour >=4 then rt=0: END IF    
    return rt
END FUNCTION

FOR i = 0 to 7
PRINT "SENT ";i;" GOT ";CONTRAST(i)
NEXT i

Gives us a little bit of a clearer picture:

Code:

Sent 0 Got 9
Sent 1 Got 9
Sent 2 Got 9
Sent 3 Got 7
Sent 4 Got 0
Sent 5 Got 0
Sent 6 Got 0
Sent 7 Got 0

So. We seem to have a complete logic failure.

0 <= 3 is FALSE and under certain circumstances 7<=3 is TRUE.

I am so going to bed. I've programmed myself into something psychedelic.

Incidentally:

Code:

FUNCTION CONTRAST (colour as uByte) as uByte
    DIM rt as uByte
    IF colour <4 then LET rt = 7: END IF
    IF colour >3 then let rt = 0: END IF
    return rt
END FUNCTION

Seems to be working.

I suppose just asking for PAPER 9 and INK 9 to work is out of the question?