VisUAL

VisUAL is a cross‑platform emulator that focuses on teaching the ARM Unified Assembly Language (UAL) instruction set. It runs a subset of ARM instructions while simultaneously displaying visual representations of concepts that are typically abstract in assembly programming, such as pointer behavior, shift operations, and memory accesses. The tool is used primarily in the Introduction to Computer Architecture course at Imperial College London, but it can serve any learner who wants an interactive way to explore ARM assembly.

The interface lets users step through code and browse the history of register values, making debugging more transparent. Visual panes show pointer details, animate shift instructions with real data, and highlight memory reads and writes, including base and offset addresses. Stack operations, branch decisions, and subroutine calls are illustrated with colour‑coded cues and arrows, while error messages explain the exact problem rather than offering vague compiler output. An infinite‑loop detector warns users before execution stalls.

VisUAL runs on macOS and is considered stable for educational use. Its emphasis on real‑time visual feedback and context‑aware error suggestions distinguishes it from generic emulators, providing a focused learning environment for ARM assembly language.