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WebAssembly or Wasm standard developed by W3C Community Group defines a bytecode
format for executable programs, as well as its text representation. The goal of the bytecode is to
enable efficient interpretation and keep the size of the binary small. Although it has been created
mainly for use on web pages, it is suited for other environments as well, including embedded
targets. Programming languages, even those with manual memory management and pointer
arithmetics, can be compiled to Wasm bytecode. Hence, a standard-conforming WebAssembly
interpreter is capable of running code written in any of the languages, for which a compiler
exists. This currently includes C, C++, C#, Rust and others. Wasm bytecode runs on a virtual
stack machine. Most existing environments either interpret it directly or use JIT compilation.
The goal of this thesis is to create a laboratory station for execution of WebAssembly on a
programmable logic device. The client is a person responsible for the equipment of a laboratory.
Project’s codename is WMC - WebAssembly Machine in Circuitry.
WebAsm interpretation could possibly be made faster with hardware designed specifically for
this task 1. Such hardware would also benefit from already existing tools for generating and
working with the bytecode. The entire range of languages, that can be compiled to the bytecode,
would be immediately available for use on such platform.
Although a WebAssembly processor would be unique in some sense, it could still be used in a
fashion similar to other soft processors for programmable logic, enabling sequential execution.
The processor could be integrated with hardware modules. Such a combination would allow for
implementing peripheral devices operated by Wasm software. If such WebAssembly processor
proves speed-efficient, it can be implemented in application-specific integrated circuit.
In terms of this thesis a laboratory station for execution of WebAssembly in a programmable
logic device is going to be created. It will consist of a selected FPGA board with a dedicated
programmer. Means of communication with the device, for example a VGA display or wired
connection to a computer, are also going to be ensured.
Wasm machine is going to be implemented in a hardware description language. Included will
be: the code, tools to generate bitstream and load it to the board, a test program in WebAssembly binary format, means of transfering it to the device and documentation for the product.
The client will be a person responsible for equipment of a research laboratory. Aside from
allowing researchers to evaluate Wasm bytecode execution on the FPGA board, the resulting
product should allow modification of the logic design, for example to add a peripheral module
or a custom instruction to the processor and perform experiments with it.
The designed Wasm machine is going to be a stack machine. Its distinguishable parts will be
control unit, arithmetic logic unit and peripheral interfaces. An in-circuit stack (as opposed to
stack fully contained in RAM) and floating-point unit might also be added. The machine shall
make use of memory module residing on the development board. It shall communicate with
devices external to FPGA chip through peripherals (e.g. VGA module, serial interface module).
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