This is the fourth part in this series, and will cover flow control instructions. You can find the first post here , the second here , and the third here . Prerequisites None of the flow control operations use the data stack, and only two make use of the return address stack, so knowing about stacks is less important in this post than in the others. Knowledge of other assembly language variants would definitely be an asset, as these follow the same patterns found in other processors. Last Time The last post covered arithmetic and logic unit (ALU) instructions, which modify the condition code (CC) register. Many of the flow control instructions make use of the CC flags to determine whether or not to move execution flow elsewhere. Jumps Jump ( jmp , jsr , rts ) instructions change the program counter (PC) to an absolute address in memory. They are all unconditional, that is, the change in the PC happens regardless of the system's state. jmp changes the PC to an address specified as ...