Register Organization

Register Organization

Registers are temporary storage locations inside the CPU.

The registers in the processor can be put in two categories:

1. User-visible registers: Enables the machine to minimize main memory references by optimizing use of registers.
2. Control and status registers: Used by the control unit to control the operation of the processor.

User-Visible Registers:

User-visible registers includes,

1. General purpose registers: General-purpose register can contain the operand for any opcode. 
   General-purpose registers can be used for addressing functions  (e.g., register indirect, displacement).
2. Data registers: Data registers may be used only to hold data and cannot be employed in the calculation of an operand address.
3. Address registers: Address registers may themselves be somewhat general purpose, or they may be devoted to a particular addressing mode. Examples include the following:
1. Segment pointers: Segment register holds the address of the base of the segment.
2. Index registers: These are used for indexed addressing and may be autoindexed.
3. Stack pointer: This allows implicit addressing; that is, push, pop, and other stack instructions need not contain an explicit stack operand.

Control and Status Registers:

1. Program counter (PC): Contains the address of an instruction to be fetched.
2. Instruction rester (IR): Contains the instruction most recently fetched.
3. Memory address register (MAR): Contains the address of a location in memory.
4. Memory buffer register (MBR): Contains a word of data to be written to memory or the word most recently read.

More topics from Computer Organization to read

Computer Organization and Architecture:

EasyExamNotes.com covered following topics in these notes.

1. Structure of desktop computers
2. Logic gates
3. Register organization
4. Bus structure
5. Addressing modes
6. Register transfer language
7. Direct mapping numericals
8. Register in Assembly Language Programming
9. Arrays in Assembly Language Programming

References:

1. William stalling ,“Computer Architecture and Organization” PHI
2. Morris Mano , “Computer System Organization ”PHI