Overview

This is just a silly tool to make it easier to write assembly for the microprocessors in SHENZHEN I/O, an awesome programming game released recently by Zachtronics.

WARNING: The source contains mild spoilers! :) You have been warned!

Now features unnecessarily pretty graphviz output using the new --dotfile argument!

Usage

> .\run_shenasm.py -h
usage: run_shenasm.py [-h] [-o OUTPUT] [-c {MC6000,MC4000,MC4000X}] [-v]
                      [--dotfile DOTFILE]
                      input

simple assembler/compiler for making it easier to write SHENZHEN.IO programs

positional arguments:
  input                 the input file to ingest

optional arguments:
  -h, --help            show this help message and exit
  -o OUTPUT, --output OUTPUT
                        the output file path
  -c {MC6000,MC4000,MC4000X}, --chip {MC6000,MC4000,MC4000X}
                        inform assembler of target chip for better diagnostics
  -v, --verbose         flag to cause more verbose output during execution
  --dotfile DOTFILE     write a graphviz compatible .dot file containing the
                        intermediate representation graph of the input

Example: Pulse Generator

# the pin we'll pulse the outputs on
alias output_pin p1

# the width of the pulses on period and off period
const on_duration 2
const off_duration 4

# the value we'll emit to the output pin during the on and off phases
const on_value 100
const off_value 0

# the actual code:
  mov on_value output_pin   # write the on value to the output pin
  slp on_duration           # sleep for the on duration
  mov off_value output_pin  # write the off value to the output pin
  slp off_duration          # sleep for the off duration
  # the microprocessors in the game automatically loop to the beginning
  # so this will run forever now

Which compiles to:

  mov 100 p1
  slp 2
  mov 0 p1
  slp 4

Assembly Syntax

The assembly used is almost entirely identical to that in SHENZHEN.IO, the only differences are:

Preprocessor Directives

There is currently only one supported directive:

• !include "some/filepath/here.asm" - textually includes the specified file in-place

'Macro' Instructions

To do

• [ ] Verify types of instruction arguments
• [ ] Verify register references exist on selected chip
• [x] Warn about exceeding memory space limitations of selected chip
• [x] Generate intermediate representation (IR) graph of input program
  • [x] Detect unused code (possibly not?)
  • [ ] Tidy up IR graph by merging consecutive conditional nodes
  • [ ] Maybe replace jump instructions with edges in IR graph?
  • [ ] Make assembler generate output FROM IR graph instead?
  • [ ] Add compiler flag to automatically remove unused code
• [ ] Detect and remove redundant labels?
• [ ] Basic optimisation (probably not?)
• [ ] Detect unused aliases/constants?
• [x] Compress label names
• [x] Error on redefinitions of alias/const names
• [x] Add support for including other files textually (preprocessor style)
• [x] Improve error reporting to use source file and source line
• [x] Make errors accumulate and prevent output, rather than immediate abort?
• [ ] Make constants evaluate simple expressions?