newtons-apple

A simple serial driven implementation of physics via an external computer and the apple ii.

This project contains multiple parts:

• A physics-server in the server folder written in golang using chipmunk 2D.
• An assembly language API contained in apple2\physics.s
• Some examples in applesoft contained in the applesoft folder.
• blocks.bas - a falling boxes physics demo.
• thrust.bas - a simple space ship flying demo.
• batgame.bas - a simple pong style bat and ball game.

building the server

With go installed:

cd server
go build .

There is a Makefile to build a totally static executable with musl-gcc.

cd server
make build

Using the server

Usage of ./physics-server:
  -baud-rate int
        Baud rate (default 19200)
  -data-bits int
        Data bits (5,6,7 or 8). (default 8)
  -list-ports
        List serial ports and exit.
  -max-delta int
        Max memory delta size (bytes) (default 64)
  -parity string
        Parity (E=even,O=odd,M=mark,S=space,N=none). (default "N")
  -serial
        Run on serial.
  -serial-port string
        Serial port to run service on. (default "/dev/ttyS0")
  -stop-bits string
        Stop bits (1,1.5,2) (default "1")
  -telnet-port string
        TCP Port to run service on. (default "5555")

It will run on telnet by default, which allows bootstrapping it with emulators with telnet serial emulation.

On some OSes, you may need to use sudo to get access to the serial hardware.

The service has been validated on an Apple //c with 19200 as the baud rate. (This was because our serial card has the crystal bug and isn't stable at 115200).

You can change CONTROLVAL in the assembly to set a different baud rate.

building the assembly

Using merlin32:

cd apple2
merlin32 physics.s

The code will by default assemble to $2000. This engine proof of concept uses lo-res for brevity, so this memory is free.