5.5.2 Rotation

Rotate operations can be performed in your code, despite the C language not including a rotate operator.

The compiler will detect expressions that implement rotate operations using shift and logical operators and compile them efficiently.

For the following code:

c = (c << 1) | (c >> 7);

if c is unsigned and non-volatile, the compiler will detect that the intended operation is a rotate left of 1 bit and will encode the output using the PIC MCU rotate instructions. A rotate left of 2 bits would be implemented with code like:

c = (c << 2) | (c >> 6);

This code optimization will also work for integral types larger than a char. If the optimization cannot be applied, or this code is ported to another compiler, the rotate will be implemented, but typically with shifts and a bitwise OR operation.