After a little creative thinking I think this may do the trick...

code:
BREAK ON
$VAR1=577
? $VAR1
$VAR2=$VAR1 - ($VAR1 & &40)
IF $VAR1 = $VAR2   ;The bit was off
     $VAR1 = $VAR1 + &40
ELSE               ;The bit was on
     $VAR1 = $VAR1 - &40
ENDIF
? $VAR1
Thanks for your input Howard. It put me on the road to binary bliss.

This could be setup as a UDF
code:
Function XOR($BinaryVal,$Bit)  ;&BinaryVal = Value of binary number // $Bit = Value of bit to swap
     Dim $TstBit
     $TstBit = $Bit
     WHILE $TstBit MOD 2 = 0 AND $TstBit <> 1
          $TstBit = $TstBit / 2
     LOOP
     IF $TstBit <> 1
          ? "The bit is not a power of 2!"
          RETURN
     ENDIF
     Dim $TmpVar
     $TmpVar=$BinaryVal - ($BinaryVal & $Bit)
     IF $TmpVar = $BinaryVal   ;The bit was off
          $XOR = $BinaryVal + $Bit
     ELSE                      ;The bit was on
          $XOR = $BinaryVal - $Bit
     ENDIF
EndFunction
Some method of checking $Bit to be sure it's a power of 2 would be good also.
*UPDATE* I went ahead and decided to be proactive and added a routine to check the $Bit value. It's inlcuded in the above UDF.

Thanks,
Ben

[ 13. September 2002, 15:49: Message edited by: Ben Dulaney ]