A register machine is a very fast, portable place on a personal computer where a user can input various events into the computer. Most registers tend to contain a limited amount of memory, which is what causes them to be called ‘affixed’ registers. Some registers can be read/write-only, while others have special hardware functions, and can only be read-write. An example of an attached register is the PC register, which is used by the Personal Computer (PC) to store application code and data. The PC register is an important part of the Windows operating system (OS) and is accessed during booting up and closing down.
The PC register saves the boot-up information, which includes settings for the operating system, access to hardware, and any stored session preferences. All memory that is accessed must be explicitly pushed into the I/O register before execution. Instructions that use more than one bit in the CPU registers are optimized to use the additional bits as they come into play during execution. Instructions that do not require any extra bits push all the memory into the I/O memory.
Another type of register hold is the memory buffer register, which has two types of data: one to hold a temporary assignment that is cleared when the instruction pointer is invalid, and another to hold an instruction that gets the CPU to carry out the instruction. The instruction pointer must be held in the I/O register for it to become valid, and then the memory buffer register is used to clear the register pointer and start execution. The PC register is the only register that may hold the PC instructions; any other registers that get pushed into the I/O memory buffer are ignored and can not hold PC instructions. All instructions that get pushed into the PC register get routed to this register first, before the memory buffer is emptied.
The other register that stores most of the instructions is the computer storage register. The index register has several purposes. First, the index register maps the PC to an address in memory address space. Then, whenever an instruction pointer comes into the system, the index register gets updated to point to where the computer will look for the instruction, and the PC is thus updated.
The other three types of registers are the instruction pointer, the target address, and the saved instruction pointer. They are used along with the memory buffer register for executing various types of computer instructions. When an instruction pointer is pushed onto the computer memory, a particular instruction will be executed. This happens whenever a programmer wants to pass an instruction to the PC. In addition, when an instruction is saved into the memory buffer register, this instruction will be reloaded whenever necessary.
Instruction sets and their various types have been a part of the microprocessor architecture since the beginning of the computer era. The instruction set is usually updated through a chip on the CPU or a ROM. However, these instructions need to be executed by the CPU before they become effective. In order to make the CPU execute instructions faster, many CPU instructions are pre-fetched from the RAM and executed on the CPU.