Example
A simple example of branch table use in the 8-bit Microchip PIC assembly language is:
movf INDEX,W ; move the index value into the W (working) register from the INDEX memory location addwf PCL,F ; add it onto the program counter register (PCL). each PIC instruction is one byte ; so there is no need to perform any multiplication. most architectures will transform ; the index in some way before adding it to the program counter table ; the branch table begins here with this label goto index_zero ; each of these goto instructions is an unconditional branch to a different section goto index_one ; of code goto index_two goto index_three index_zero ; code is added here to perform whatever action is required when INDEX was equal to zero return index_one ...Note: this code will work only if PCL < (table + index_last). To ensure this condition we may use "org" directive. And if GOTO (PIC18F for example) is 2 bytes, this limits table entries to less than 128.
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