1. An apparatus comprising: a processor; and a memory that stores an instruction of an application, the instruction including an opcode and an operand, wherein the operand specifies: an immediate value; or a register indicator of a register storing the immediate value, wherein the immediate value identifies a function call address that is selectable from a table that includes a plurality of function call addresses corresponding to a set of functions of the application, the set of functions including frequently used functions of the application as determined by a compiler or by a linker, the table excluding a function call address of a function of the application that is less frequently used than any of the frequently used functions, and wherein the processor is configured to dynamically update the table.