Instruction dispatch involves fetching/reading an instruction from
memory, and jumping to the corresponding segment of code that implements
In a stack based architecture an addition would look like:
I1: LOAD C
I2: LOAD B
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.