How a CPU Processes Intructions | Generated by AI
This image appears to be a page from a textbook or lecture notes on computer architecture, specifically focusing on the design of a CPU (Central Processing Unit) with a focus on the Memory Address Register (MAR) and its related operations. Here’s a detailed explanation of the content:
Text Description:
- Introduction:
- The text mentions a 16-bit CPU and discusses the role of the Memory Address Register (MAR) in the CPU’s operation.
- The MAR is described as a 16-bit register used to store memory addresses.
- Operations Involving MAR:
- Instruction 1: The text describes an operation where the content of register R2 is subtracted from the content of register R1, and the result is stored back in R1. Additionally, the content of MAR is moved into R1.
- Instruction 2: The text mentions another operation involving the MAR, but the specific details are not fully visible in the image.
Diagram Description:
The diagram illustrates the structure and flow of data within a CPU, highlighting the interaction between various registers and the Arithmetic Logic Unit (ALU). Here are the key components:
- Registers:
- IR (Instruction Register): Holds the current instruction being executed.
- PC (Program Counter): Keeps track of the address of the next instruction to be executed.
- MAR (Memory Address Register): Stores the address of the memory location being accessed.
- MDR (Memory Data Register): Holds the data being read from or written to memory.
- R1 and R2: General-purpose registers used for temporary storage and manipulation of data.
- Y: Another register involved in data processing.
- ALU (Arithmetic Logic Unit):
- Performs arithmetic and logical operations on the data held in registers.
- The ALU has inputs A and B, and outputs Z.
- Operations include addition (ADD), subtraction (SUB), and bitwise operations (1-Cx).
- Data Flow:
- The diagram shows the flow of data between the registers, the ALU, and memory.
- Arrows indicate the direction of data transfer, such as from MAR to the memory address bus and from the memory data bus to MDR.
Summary:
The image provides an overview of how a CPU processes instructions, focusing on the role of the MAR in addressing memory and the interaction between various registers and the ALU. The text and diagram together illustrate the fundamental operations of a CPU, including data transfer and arithmetic/logical operations.