Wipforth

Building and Running

To run, first compile the WebAssembly module:

wat2wasm --enable-threads wipforth.wat

Then run the server:

python3 server.py

You should then be able to open http://localhost:8080 in a browser and use the system from there.

NOTE: The server is just a very simple instantiation of Python's built-in http.server that sets the cross-origin headers required for SharedMemoryBuffer use. You could use any HTTP server that sets these headers.

Peripherals

Serial

Name	Offset	Size / B	Access
TXBUF	0	32	write
RXBUF	32	32	read
TXHEAD	64	1	atomic read
TXTAIL	65	1	atomic write
RXHEAD	66	1	atomic write
RXTAIL	67	1	atomic read

For both sending (TX) and receiving (RX), there are three registers: xBUF, xHEAD and xTAIL:

• xBUF registers are 32-byte FIFO ring buffers used for data
• The xHEAD and xTAIL registers specify the start and end of data in the ring buffer, xHEAD being the offset of the first byte of data, and xTAIL being the offset of the first byte after the data.

In order to be distinguishable from the empty state, the ring buffers must never be completely full -- there must always be at least one unoccupied byte between the tail and the head.