1.1.1a: The Arithmetic and Logic Unit; ALU, Control Unit and Registers (Program Counter; PC, Accumulator;ACC, Memory Address Register; MAR, Memory Data Register; MDR, Current Instruction Register; CIR).Buses: data, address and control: how this relates to assembly language programs.
| Keyword | Definition |
|---|---|
| Accumulator | General purpose register within the ALU which stores the input and/or output of any calculations |
| Address Bus | Part of the system bus which transmits the memory location of data to be read from or written to. Links the CPU and immediate access store. |
| Arithmetic Logic Unit | Part of the CPU which processes data by performing logical and arithmetic operations. |
| Assembly language | low level code where each operation that the CPU will execute is represented by a separate instruction in code |
| Control Bus | Part of the system control bus which transmits signals which synchronise and trigger how different parts of the computer work together. |
| Control Unit | Part of the CPU which sends control signals to initiate and syncronise each part of the fetch, decode, execute process |
| Current Instruction Register | A register inside the control unit which stores the value of the instruction which has just been fetched. |
| Data Bus | Part of the system bus which carries data and instructions between the CPU and immediate access store |
| Immediate Access Store | Memory storage locations which can accessed in one clock tick (without any delay) |
| Memory Address Register | A register used to store the location of memory currently being being read from or written to |
| Memory Data Register | A register that works as a buffer between the CPU and the immediate access store which stores the data or instruction currently being transferred on the data bus. |
| Program Counter | Register which stores the address of the next instruction to be executed |
| Register | Very fast memory located inside a CPU with only enough capacity to store an individual value or instruction. |
| System Bus | A group of digital connections that work as a common pathway to send binary data between components of a computer |
