what is the meaning of Instruction dispatch

Question

Can any-one tell me what is the exact meaning of instruction dispatch and how Register based architecture avoid instruction dispatch ?

Answer 1

Instruction dispatch involves fetching/reading an instruction from memory, and jumping to the corresponding segment of code that implements the instruction.

In a stack based architecture an addition would look like:

I1: LOAD C
I2: LOAD B
I3: ADD
I4: STORE A

You fetch the values from the stack and push the result back on it (hence the name stack based architecture).

In a register based architecture:

I1 "ADD, a, b, c"

a,b,c being registers.

A register based architecture does not completely avoid fetching instructions but it reduces the number of them.