The #pragma Switch Directive

Normally, the compiler encodes switch statements to produce the smallest possible code size. The #pragma switch directive can be used to force the compiler to use a different coding strategy.

The switch pragma affects all subsequent code and has the general form:

#pragma switch switchType

where switchType is one of the available selections that are listed in the Table 1 tables. The only switch type currently implemented for PIC18 devices is space.

Table 1. Switch Types
Switch Type	Description
`speed`	Use the fastest switch method.
`space`	Use the smallest code size method.
`time`	Use a fixed delay switch method.
`auto`	Use smallest code size method (default).
`direct` (deprecated)	Use a fixed delay switch method.
`simple` (deprecated)	Sequential xor method.

Specifying the time option to the #pragma switch directive forces the compiler to generate a table look-up style switch method. The time taken to execute each case is the same, so this is useful where timing is an issue, e.g., with state machines.

The auto option can be used to revert to the default behavior.

Information is printed in the assembly list file for each switch statement, showing the chosen strategy (see Switch Statement Information).