Question

Class: Assembly Language x 86 Processors

I need help reviewing the following topics:

1.) Define a bit, byte, and a nibble.

2.) Define a program, a register, Cache Memory.

3.) What is the meaning of backward compatibility?

4.) List & define x89 processor Modes

5.) What is the processor's operation (Instruction Execution) Cycle ( I am most confused on this topic)

6.) List the processor's Basic registers.

Answer 1

1) A bit (short for binary digit) is the smallest unit of data in a computer. A bit has a single binary value, either 0 or 1.

A nibble has 4 bits and a byte has 8 bits of storage.

2)

EAX used to be called the accumulator since it was used by a number of arithmetic operations, and ECX was known as the counter since it was used to hold a loop index.

Whereas most of the registers have lost their special purposes in the modern instruction set, by convention, two are reserved for special purposes — the stack pointer (ESP) and the base pointer (EBP).

For the EAX, EBX, ECX, and EDX registers, subsections may be used.

For example, the least significant 2 bytes of EAX can be treated as a 16-bit register called AX. The least significant byte of AX can be used as a single 8-bit register called AL, while the most significant byte of AX can be used as a single 8-bit register called AH.

When a two-byte quantity is placed into DX, the update affects the value of DH, DL, and EDX. , they are sometimes convenient when dealing with data that are smaller than 32-bits (e.g. 1-byte ASCII characters).

When referring to registers in assembly language, the names are not case-sensitive. For example, the names EAX and eax refer to the same register.

4) addressing modes

Immediate
• Direct
• Indirect
• Register
• Register Indirect
• Displacement (Indexed)
• Stack

3)backward compatible assembly languages, which provide some level of compatibility all the way back to the Intel 8008 introduced in April 1972.