1. What are program-visible registers?

1. What are program-visible registers?

The register which can be accessed directly by a program they are called visible registers.

 

2. What are program-invisible registers?

            The program invisible registers are used to access and specify the address tables of global and local descriptor tables. - Since these types of register cannot be accessed directly by a program they are called invisible registers.

 

2. The 80286 addresses registers that are 8 and 16 bits wide.

 

3. The extended registers are addressable by 80386 microprocessors.

 

4. The extended BX register is addressed as EBX.

 

5. ECX register holds a count for some instructions , it is general purpose register and in 80386 and above processors can hold offset address of memory data.

 

6. What is the purpose of the IP/EIP register?

The EIP register always contains the address of the next instruction to be executed. · You cannot directly access or change the instruction pointer.

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Intel microprocessors ,

8086/8088, 80186/80188, 80286, 80386, 80486, Pentium,

Pentium Pro Processor, Pentium II, Pentium III, Pentium 4,

and Core2 with 64-Bit Extensions

Architecture, Programming, and Interfacing

THE MICROPROCESSOR AND ITS ARCHITECTURE