Intel has unveiled an extensive test suite designed for the 80286 microprocessor.
A groundbreaking test suite for the Intel 80286 chip has been released, offering a detailed collection of tests designed to verify the CPU's behaviour and instruction execution accurately. The suite, developed by Daniel Balsom, focuses primarily on the real mode operation of the 80286.
Purpose and Applications
This test suite serves multiple purposes:
- Validation and Debugging of Physical CPUs: The suite can be used as a chip-tester by feeding instructions into a physical 80286 CPU and validating its outputs and behaviour cycle-accurately.
- Emulator Development and Verification: The test suite is instrumental for emulator authors to develop cycle-accurate emulators for the 80286, such as the MartyPC emulator, ensuring the software mimics the real hardware precisely.
- Hardware Research: It helps in rediscovering and documenting obscure or lost details about the 80286’s internal operation, like interrupt handling and prefetch queue behaviour.
Platforms and Usage
The test suite can be used in conjunction with two platforms:
- ArduinoX86: This microcontroller-based platform controls and tests vintage CPUs like the 80286. The ArduinoX86 runs the comprehensive tests and collects detailed CPU state information by single-stepping through instructions. It acts as an interface between the test software and the physical 80286 hardware, enabling cycle-accurate validation.
- MartyPC: MartyPC is Daniel Balsom’s cycle-accurate emulator for vintage Intel-compatible CPUs, including the 286. The test suite aids MartyPC’s development by providing a rigorous benchmark against the real CPU’s behaviour. Passing the test suite ensures the emulator's correctness and timing accuracy.
Key Features
The real mode test suite contains 326 instruction forms and over 32 million cycle states, capturing the behaviour of the 80286 chip from 1986. It is available publicly on GitHub under an MIT license, including repositories for the test generation code, the ArduinoX86 CPU controller, and the MartyPC emulator itself.
It's important to note that the tests currently cover only real mode operations of the 80286, excluding protected mode or “unreal mode” tests, with plans to extend coverage in the future.
Daniel Balsom encourages readers to share any new findings about Intel's old processors, or any other processors, with the tipsline. The creation of this test suite is a significant step towards understanding and preserving the history of vintage CPUs.
The test suite created by Daniel Balsom, focusing on the real mode operation of the 80286, can be utilized with the ArduinoX86 platform, a microcontroller-based tool that controls and tests vintage CPUs like the 80286, collecting data and cloud computing information. Additionally, the MartyPC emulator, another platform instrumental in developing cycle-accurate emulators, benefits from the rigorous benchmark provided by the suite, paving the way for data-and-cloud-computing research and applications involving the 80286 chip.
