The description of how ALU interacts with the processor is given below. Every arithmetic logic unit includes the following configurations:
- Instruction Set Architecture
- Register to Register
- Register Stack
- Register Memory
The intermediate result of every operation is contained by the accumulator, which means Instruction Set Architecture (ISA) is not more complex because there is only required to hold one bit.
Generally, they are much fast and less complex but to make Accumulator more stable; the additional codes need to be written to fill it with proper values. Unluckily, with a single processor, it is very difficult to find Accumulators to execute parallelism. An example of an Accumulator is the desktop calculator.
Whenever the latest operations are performed, these are stored on the stack that holds programs in top-down order, which is a small register. When the new programs are added to execute, they push to put the old programs.
It includes a place for 1 destination instruction and 2 source instructions, also known as a 3-register operation machine. This Instruction Set Architecture must be more in length for storing three operands, 1 destination and 2 sources. After the end of the operations, writing the results back to the Registers would be difficult, and also the length of the word should be longer. However, it can be caused to more issues with synchronization if write back rule would be followed at this place.
The MIPS component is an example of the register-to-register Architecture. For input, it uses two operands, and for output, it uses a third distinct component. The storage space is hard to maintain as each needs a distinct memory; therefore, it has to be premium at all times. Moreover, there might be difficult to perform some operations.
Register – Stack Architecture
Generally, the combination of Register and Accumulator operations is known as for Register – Stack Architecture. The operations that need to be performed in the register-stack Architecture are pushed onto the top of the stack. And its results are held at the top of the stack. With the help of using the Reverse polish method, more complex mathematical operations can be broken down. Some programmers, to represent operands, use the concept of a binary tree. It means that the reverse polish methodology can be easy for these programmers, whereas it can be difficult for other programmers. To carry out Push and Pop operations, there is a need to be new hardware created.
Register and Memory
In this architecture, one operand comes from the register, and the other comes from the external memory as it is one of the most complicated architectures. The reason behind it is that every program might be very long as they require to be held in full memory space. Generally, this technology is integrated with Register-Register Register technology and practically cannot be used separately.