4.5.4 Switch Statements

By default, jump tables are used to optimize switch() statements. This can be made explicit by using the -fjump-tables option. The -fno-jump-tables option prevents jump tables from being used and will use sequences of compare sequences instead. Jump tables are usually faster to execute, but for switch() statements where most of the jumps are destined for the default label, they might produce excessive amounts of code.

Jump tables use the limited-range lpm assembler instruction. Always use the -fno-jump-tables option when compiling a bootloader for devices with more than 64 KB of program memory.