The Ember CPU — Initial Design Part 6: Jumps and Conditional Branches

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Now that we have Load-Store and common ALU instructions, we can add branching and jump instructions to the Ember CPU design.

Branch Instructions

Branches are useful when you want a CPU to repeat some operations multiple times, skip over other operations, or temporarily go to a subroutine nearby in the same program or library. They can also be used to call code in a library provided by the system, or code linked together with the program at compile time.

The definitions of Jump and Branch are a bit loose, but for our case, the simplest definition is that a Branch instruction may or may not be taken, depending on various condition flags in the CC status register, where a Jump instruction will always be taken.

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