Chapter 1: Instructions Flashcards
Why do we use an assembly language?
This is because it is hard to remember all of the specific binary codes for different operations.
What is a complex Instruction set (CISC)
Occurs when there is a large number of instructions, all of these instructions need to be retained in order to allow old programmes to still work.
What is a Reduced Instruction set (RISC)
Normally faster hardware that has been adapted to use a small instruction set using a limited number of basic functions.
Disadvantages of RISC?
The danger with RISC architectures is that as they evolve, they transform into a CISC architecture. For example, the ARM RISC architecture initially had 46 instructions. More recently the latest processor has more like several hundred.
Disadvantages of CISC?
- The hardware required for lots of instructions (often consisting of variable numbers of bits) is harder to design and optimize for low power operation.
- Furthermore, some of these instructions took longer to carry out than others, making it more difficult to optimize the speed.