Processor Architecture

Compare the architectural features of 32 bit and 64 bit architectures.

The 32 bit and 64 bit architectures explains

• The no. of bites it can handle.
• The size of the data it can store. A 32 bit processor have upto 4GB of RAM, a 64 bit processor is recommended if more than 4GB is needed.

The comparison between the two is explained in the table

Sr. No.	32-bit	64-bit
1.	They are not backward compatible, that is a 32-bit processor cannot work on a 64-bit processor.	They are backward compatible. Any 64-bit processor can work on a 32-bit processor.
2.	Can address to maximum upto 4GB of memory.	Can address nearly 4 billion times the memory locations as provided by a 32-bit.
3.	Less efficiency and less RAM.	Highly efficient and have comparatively wider RAM.
4.	Compatible with addresses that are 4 octet wide.	Compatible with addresses that are 8 octets wide.
5.	Available on windows 8, windows 7, windows XP.	Available on windows 8, windows 7, XP professional as well as on Mac OS X.
6.	Applications with fewer memory needs are advisable.	Applications with higher memory needs like video games etc are advisable.
7.	Less secured as the encryption and decryption tasks takes time.	Highly secured as the security operations are carried out quickly and effectively.

Write a short note on functional units of Pentium processor.

• Pentium processor is the personal computing microprocessor by Intel.
• Its basic functional units are as follows:

1. BUS UNIT: It provides a connection for the interaction between processor and the system. It performs its function by bringing the code and the data together in the pipeline separates them in it to get executed and then recombines it and sends back. This is called as ”bus cycle”.

2. PREFETCHER: It requests for the instructions from the code memory, if the instruction is not available in cache, a bus cycle is performed in the external memory to fetch it.

3. INSTRUCTION DECODER: The instructions that has been fetched from the code cache by the PREFETCHER has to be decoded into signals. This is done at two levels:

• Decode1: To check if the instructions can be paired.
• Decode2: If they can be paired they are put together in second decode.

4. CONTROL UNIT: The instructions after decode are provided to the control unit which then handles them for any errors or breakpoints.

5. ARITHEMATIC AND LOGIC UNIT: This unit performs the arithmetic and logic operations.

6. FLOATING POINT UNIT: It carries out the non-integer type of calculations.