SIMPOL Documentation

Bitwise operators are used for applying boolean operations at the individual bit level of a value. They are commonly used to set and test flag values where a single 32-bit integer may carry 32 different values in one integer. This is a very efficient way to pass a number of options in a single value. Bitwise operators are also commonly used in hashing, compression, and encryption algorithms, among others. Use of these operators is generally the province of advanced programmers and they should not be used in place of the Boolean equivalents, since although they may sometimes work, they could produce unexpected results. The bitwise operators are AND, OR, and XOR. These should not be confused with the lowercase operators of the same name in the case of AND and OR, which are the Boolean operators.

For those unfamiliar with bitwise operators, they operate on the individual bits where each bit contains only 0 or 1. The AND operator compares two values and only returns the value 1 if both bits contain a 1, otherwise it returns 0. The OR operator compares two values and returns 1 if either of the bits contain 1, otherwise it returns 0. The XOR operator compares two values and returns 1 if one of the two values has a bit set and the other does not. If both values are the same (both 1's or both 0's), then it returns 0. The following tables may help clarify things:

A common use for the AND operator is as a test to see if a bit is set in a value.

A common use for the OR operator is to set a bit in a value independent of its current state.

A common use for the XOR operator is to toggle a bit in a value. Using XOR twice with the same operands will return the value back to its starting point.