### Unary/Bitwise NOT (!) As we discussed in the previous section *NextBASIC* provides one additional unary operator, which is an operator that requires one number alone. This is: | | | |---|---| | ! | bitwise NOT | *Bitwise NOT* inverts the bits of said number from **0** to **1** and vice-versa. | | | | |---|---|---| | `PRINT %!15` | returns **65520** as **15** gets inverted
to become **65520** | **(0000 0000 0000 1111)**
**(1111 1111 1111 0000)** | | `PRINT %!43690` | returns **21845** as **43690** gets inverted
to become **21845** | **(1010 1010 1010 1010)**
**(0101 0101 0101 0101)** | this seems pretty straightforward correct? Wrong because look at what happens once you omit the **%** symbol and the expression is no longer an integer one: | | | | |---|---|---| | `PRINT !43690` | returns -**43691** as **43690** gets inverted **together** with its *sign bit*
to become -**43691** | **(1010 1010 1010 1010)**
**(0101 0101 0101 0101)** | what happened can be found in a simple phrase: *two's complement* which we'll examine further below. Until then however run the following examples: ``` 10 PRINT !32767 20 PRINT %! 32767 30 PRINT % SGN{!32767} ``` if you feel a bit overwhelmed, not to worry; soon all will be very clear! ### Bitwise operators <<, >>, &, |, ↑, ↑| *NextBASIC*, can also perform 5 *bitwise operations* (that is operations on the individual binary digits that make up a number) on variables and expressions. These are: | | | |---|---| | *x* << *y* | Shift each bit of *x*, *y* places left | | *x* >> *y* | Shift each bit of *x*, *y* places right | | *x* **&** *y* | Bitwise AND between *x* and *y* | | *x* \| *y* | Bitwise OR between *x* and *y* | | *x* ↑ *y* | Bitwise XOR between *x* and *y* *(Deprecated, use the next one)* | | *x* ↑\| *y* | Bitwise XOR between *x* and *y* (Synonym with the previous) | More information on Bitwise operations together with examples (as binary examples are much easier to understand) can be found in *Integer Expressions* below. The operators however work on both (except for the deprecated one) Integer and Floating Point expressions ### Logical operators Standard logical operators can be used within integer expressions if prefixed by a **%**. These are used in the same manner as their floating point counterparts. | | | |---|---| | *x* **AND** *y* | Logical *AND* (gives 0 if *y* is zero, *x* if *y* is non-zero) | | *x* **OR** *y* | Logical *OR* (gives *x* if *y* is zero, 1 if *y* is non-zero) | | **NOT** *n* | Logical *NOT* (zero -> 1, non-zero -> 0) |