A register is a processor-oriented device that a computer can use to store multiple values, instructions, or strings of information. Many register files are used within a computer to store such information. The most basic register file stores a single value such as the number 1, which is commonly known as the program counter. Other types of register files hold values that refer to instructions, or data that is stored on the CPU. A register file can also hold instructions for the computer to follow when executing a certain set of instructions.
Instructions are instructions that instruct the computer how to do something. These instructions are stored in memory, which is then controlled by the various instructions that are executed from pc to pc inside the CPU. PC’s typically contain many different instructions that are stored in various registers. In most cases, every instruction that the computer executes results in one or more PC registers being hit. A register can only be hit multiple times before it becomes unusable.
PC’s instructions can be divided into two different categories: 32-bit instructions and 64-bit instructions. A typical instruction that a programmer uses will be a constant instruction, which means that it will not change any of the registers, but instead remains constant throughout the execution of the instruction. Constant instructions will save the register from getting corrupted, so that they will remain available for use after the instruction has been completely performed. Another type of instruction will be a variable or index register, which will be stored for each instruction that is executed and will not change no matter how the instruction is used.
A memory buffer register stores the execution history of an instruction, which saves it in the memory buffer register and will become invalid once the instruction is complete. Memory buffer registers also make up the difference memory of PC’s that are on the lower half of the CPU. The lower half of the CPU contains internal registers that get saved only when we execute a particular instruction.
When we execute a specific instruction, the PC will then search through all of its PC registers to find the corresponding PC register that corresponds to the executed instruction. The PC register that gets searched for will be either loaded with default contents, or zero if it was never saved, making it an active microcoded read only register. In other words, when we execute a specific instruction, the instruction pointer will be moved into the region of memory where the PC register will be located, making the PC register into an active microcoded read only register. We then execute the instruction. Once this happens, the execution ends, and control moves to the next instruction in the program.
A microcoded read/write register is used mainly within the x86 instruction set. This type of register is divided up into two sections: the machine code section and the memory address unit, also known as the RAM. The machine code sections contain machine code that is executed directly by the x86 processor; the memory address unit holds the data that is accessed by the software. There are two types of microcoded read/write registers: virtual and static. The virtual register allows instructions that are not dependent on any other registers to be stored and executed; the static register stores instructions that are dependent on the current instruction and is only influenced by the previous instructions stored in the memory address unit.