Fixed vs Variable Length Instructions

Computer CPU's may use instruction sets that have either a fixed or variable length of instructions. Variable-length instructions require multi-step fetch and decode, but allow for a much more flexible and compact instruction set. Fixed-length instructions allow easy fetch and decode, and simplify pipelining and parallelism. They do however require more memory as some instructions will be larger than required (Halt or Break for example may require no operands, but would have to occupy the same memory as instructions that do). In addition, this video explorer which types of processors commonly use fixed and variable length instructions. Please like this video and subscribe and would like to see more like it! https://www.youtube.com/channel/UC8fdekVhEilBTuBK322WjVw?sub_confirmation=1 It is part of my Computer Organization and Architecture course which you can find here: https://www.youtube.com/playlist?list=PL0_aoTs5sGaTt4IuF7jJxqVm4uE-TgsJR If you have not seen the Little Man Computer (LMC) series of videos, they are highly recommended before this one you can find them here: * A recommended introduction to Little Man computer video here: https://youtu.be/4T60r42o9Wo * A "Hello LMC" video where we do a smaller program and talk more in-depth about the instruction cycle and basic instructions: https://youtu.be/QneVgKf2eVg * And an intermediate step where we introduce branching and explore recreating conditional statements with LMC: https://youtu.be/fXMCnzdNemc * Finally we explore iteration, labels and advanced LMC: https://youtu.be/hFg1etP_sFM Here are presentation slides that can be used as a supplement to follow along and as a future reference for this content: https://drive.google.com/file/d/150yd7RGaBvlvCoqACdUn9jUYeZEL6hin/view?usp=sharing