8 bit and 32 bit ALU

                 In Micro controller system when we compare these ALUs both can do the same function. ALUs can add, subtract, multiply act, two numbers. But the difference is the speed and efficiency of these ALUs.

                 An 8 bit ALU would have to execute four instructions to add 32 bit number but 32 bit ALU can do it in one instruction. It is four times faster than 8 bit ALU.

8 bit and 32 bit ALU

 

8-bit ALU architectures are those that are based on registers, address buses, or data buses of that size. 8-bit is also a term given to a generation of computers in which 8-bit processors were the norm.

Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their address space is limited to 64 Kb. This is not a "natural law", however, so there are exceptions.

The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295 or −2,147,483,648 through 2,147,483,647 using two's complement encoding. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory.

The external address and data buses are often wider than 32 bits but both of these are stored and manipulated internally in the processor as 32-bit quantities