# CPU Simulator — Develop & Run Assembly Code > Interactive CPU simulator for learning computer architecture and the fetch-decode-execute cycle. (iPhone/iPad app by Andrew Palombo.) - Source: https://appshunter.io/ios/app/cpu-simulator/id1544486809 (this page in markdown: same URL + `.md`) - Developer: [Andrew Palombo](https://appshunter.io/developer/1544486811) - Category: Education - Price: Free - Rating: 3.60/5 from 5 App Store ratings · 6 written reviews indexed - Age rating: 4+ - Requires: iOS 14.0 · 2 MB - Languages: English - Released: 2021-01-22 - Data updated: 2026-06-02 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/cpu-simulator/id1544486809/reviews.md ## What is CPU Simulator? CPU Simulator is intended for students studying A-Level AQA Computer Science, who need to understand certain information on how a computer’s CPU functions. Specifically, the fetch-decode-execute cycle and how components of the processor change at each stage – depending on the code being run. An interactive interface shows the components of the CPU, their contents, a description of what has changed in one clock cycle, an IDE to develop assembly code, an interface to view corresponding machine code, an interface to change preferences and more. Components you can track: • Address Bus • Data Bus • Clock • Program Counter (PC) • Current Instruction Register (CIR) • Memory Address Register (MAR) • Memory Buffer Register (MBR) • 128 General Purpose Registers • Arithmetic Logic Unit (ALU) • Status Register • 128 Data Memory Locations • Instruction Memory Options you can change: • Run Speed (including stepped mode) • Number Base This is a document-based application which means that you can create and run an unlimited number of unique simulations, save and share them. This app is primarily intended to help teach ‘4.7.3.2 The Fetch-Execute cycle and the role of registers within it’ of the AQA A-Level specification, using the Harvard Architecture. ## Key features - Fetch-decode-execute cycle visualization - Interactive CPU component tracking - Assembly code IDE - Machine code view - Adjustable run speed and number base - Document-based simulations - Save and share simulations ## Recent user reviews (6 of 6) All indexed reviews: https://appshunter.io/ios/app/cpu-simulator/id1544486809/reviews.md ### 5/5 — Cool app *2024-06-23* Please consider open sourcing!!! The community can help maintain and add new features ### 4/5 — Branching Operations don’t work *2023-08-16* Hope to see some updates, Please update! Nicely formatted app with pretty good visual appeal to it, but I’ve noticed that the app almost always crashes when using branching operations within the code. ### 2/5 — Everything breaks when you try to Branch *2023-06-05* Great app with a nice GUI, but when you try to use the Branch Operation, everything completely crashes and gets stuck -(whether conditional or not). Very unfortunate because it means you can’t create any loops :( sad because the app looks so nice, and seems like a really thoughtful design. Hoping for an update to fix this issue! Please update soon!?!? ### 3/5 — “Challenging to Use Without Clear Documentation: Three Stars” *2023-04-21* I found this simulator to be somewhat challenging to use, as I was unable to determine which assembly language was being used by the software. Despite my best efforts to locate documentation or reach out to the developer, I was unable to obtain this information. Without a clear understanding of the assembly language being simulated, I found it difficult to use the software to its full potential. Overall, I appreciate the concept behind this simulator, but I would have appreciated more transparency from the developer regarding the assembly language used. It’s possible that other users will have an easier time with this software if they are more familiar with the specific language used, but for me, the lack of clarity made it frustrating to use. ### 1/5 — Feels btec *2021-12-16* People that use this app definitely get their weekly shop in Poundland ### 5/5 — Good I guess *2021-09-10* It’s a good app but it needs more controls such as adding a screen and memory for it. The app also needs the ability to write the machine code without asm. ## Frequently asked questions about CPU Simulator ### What is CPU Simulator used for? CPU Simulator is designed to help students understand how a computer's CPU functions, specifically focusing on the fetch-decode-execute cycle and the role of various processor components and registers. ### What specific A-Level Computer Science topics does CPU Simulator cover? The app directly addresses section '4.7.3.2 The Fetch-Execute cycle and the role of registers within it' of the AQA A-Level specification, using the Harvard Architecture. ### Can I write and run my own code in CPU Simulator? Yes, CPU Simulator includes an Integrated Development Environment (IDE) where you can develop assembly code and view its corresponding machine code. ### What CPU components can I track in CPU Simulator? You can track numerous components including the Address Bus, Data Bus, Clock, Program Counter (PC), Current Instruction Register (CIR), Memory Address Register (MAR), Memory Buffer Register (MBR), 128 General Purpose Registers, ALU, Status Register, 128 Data Memory Locations, and Instruction Memory. ### Does CPU Simulator support offline use? The application is document-based, allowing for the creation and running of unlimited simulations. While not explicitly stated, its core functionality suggests it can be used offline for learning and practice. ### How does CPU Simulator handle progress tracking? CPU Simulator allows users to create, save, and share unlimited unique simulations. This document-based approach enables users to revisit and refine their understanding of different code executions and CPU states. ### Is CPU Simulator suitable for beginners? The app is primarily intended for students studying A-Level AQA Computer Science, suggesting it's tailored for those with some foundational knowledge. However, its interactive nature could also benefit motivated beginners interested in computer architecture. ### Does CPU Simulator have ads? No, CPU Simulator does not contain advertisements. It is a free application focused on providing an educational experience without interruptions. ## Version history (last 1 release) ### 0.1 — 2021-01-23 No release notes. ## Apps similar to CPU Simulator | App | Rating | Price | Category | | --- | --- | --- | --- | | [Neural Network](https://appshunter.io/ios/app/neural-network/id1529389288) | 4.7 (130) | Free | Education | | [Speak English:Learn Adjectives](https://appshunter.io/ios/app/speak-englishlearn-adjectives/id1514392922) | 4.0 (9) | Free | Education | | [Quick Protect](https://appshunter.io/ios/app/quick-protect/id1585862846) | 4.8 (6) | Free | Education | | [Insight Mr Bit Lite](https://appshunter.io/ios/app/insight-mr-bit-lite/id1447051619) | — | Free | Education | | [NetSupport Browser](https://appshunter.io/ios/app/netsupport-browser/id1448383679) | — | Free | Education | | [Learn C++ - OnePercent](https://appshunter.io/ios/app/learn-c-plus-plus-onepercent/id1539345030) | 4.0 (4) | Free | Education | ## Related topics [cpu simulator](https://appshunter.io/ios/topics/cpu-simulator) · [the motherboard](https://appshunter.io/ios/topics/the-motherboard) · [motherboard](https://appshunter.io/ios/topics/motherboard) · [simulador cpu neander mobile](https://appshunter.io/ios/topics/simulador-cpu-neander-mobile) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-02.*