The Fetch / Execute /. Decode Cycle. This animation will show the process. Registers. Memory. of the fetch / execute / decode cycle. of the CPU. Some of steps. Back. Registers and the Fetch-Decode-Execute cycle. Registers A Von Neumann CPU (the type of CPU you get in nearly all personal computers) has a number. Fetch decode-execute presentation. 1. Fetch-Decode-Execute Cycle; 2. THE FETCH – EXECUTE CYCLE Both the data and the program that.

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These are very fast memory circuits.

You can think of each register as a box which holds a piece of data useful to the CPU. These pieces of data allow the CPU to quickly ‘fetch’ and then ‘decode’ and then ‘execute’ the instuctions held in RAM that are part of a program, fdtch instruction at a time.


Instruction cycle

Using registers to execute an instruction in a program. Consider the following situation: Note in the above that we have not used binary either for the RAM address or the contents, to make things easier to ftech

This is because that is all the CPU actually does. It fetches instructions, decodes them and then executes them.

It does this very quickly indeed, but that is all it does. It is why you sometimes read that computers aren’t very clever! The registers you should know about include: Index register – this is a very fast counter, that is used e. How are the registers used to read an instruction in a program?

Registers and the Fetch-Decode-Execute cycle

In our case As soon as it is read, the PC increments. The contents of this address are moved to the MDR.

The MDR now holds the instruction that must be executed. Part of the instruction might be an operation like ADD and part of the instruction might be data, or in our case, an address where data can be found, like The operand exexute put back on the MAR.


Arithmetic and logical instructions are carried out using the Accumulator s in a CPU.

CICLO FETCH DECODE EXECUTE by Princess Molecula on Prezi

In our example, this will result in adding to whatever is in the Accumulator, and then over-writing the contents of the Accumulator with the result of the addition. Organisation of data 7. The operating system 9. Algorithms and programs Principles of programming Edecute of software systems Data security and integrity Economic, moral, legal, ethical and cultural issues.