The Registers in the CPU
What does the register do?
Registers receive the information from memory or from the CPU, hold it temporarily and pass it on as directed by the control unit. Registers are tied to a clock, where an instruction in the register is executed in one clock cycle. The number of registers varies from computer to computer; each one is designed to perform a specific function. Registers have a specific storage capacity depending on the number of bits they are designed with. Normally 14 registers are present in a microcomputer.
1]The accumulator register is a special data register and it stores the result of the last processing step of the ALU.
2]User visible registers are divided into to data registers and address registers.
3]Address registers are used to hold memory registers and the next piece of data.
4]Data registers store data.
5]Condition registers are used to determine whether the instruction should execute or not.
6]Constant registers are used to store read only values.
7]Floating point registers store floating point numbers.
8]General purpose registers hold the data and addresses.
9]Special purpose registers are used to store the status of the program and it consists of program counter,
10]stack pointer and
12]The program counter holds the address of the next instruction to executed.
13]The instruction register holds the instruction while it is being executed.
14]The index register stores an index of memory addresses.
You can read about A Visual Interpretation of How a CPU Works and learn additional information about registers.