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README.md

Uxn

A stack-based VM, written in ANSI C.

Build

cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn

Assembly Syntax

  • :label, a named address
  • +literal, a numeric value
  • .pointer, pointer to a label
< conditionals >

0302	ADD 
05		EQU

.there	JMZ

:here
	< when not equal >
	ee
	BRK

:there
	< when is equal >
	ff
	BRK

Mission

  • constants
  • variables
  • A Three-Way Decision Routine(http://www.6502.org/tutorials/compare_instructions.html)
  • Carry flag?
  • Loop
  • Pointers/Literals
  • Print word to stdout
  • Draw pixel to screen
  • Detect mouse click
  • Jumps should be relative
  • Catch overflow/underflow
  • Audo-detect literals length.
  • SDL Layer Emulator
  • Build PPU
  • Interrupts

16 Bit Missions

  • 16 bits addressing
  • jumping to subroutine should be relative
  • Implement addressing
  • Implement 16 bits operations

Refs

https://code.9front.org/hg/plan9front/file/a7f9946e238f/sys/src/games/nes/cpu.c http://www.w3group.de/stable_glossar.html http://www.emulator101.com/6502-addressing-modes.html http://forth.works/8f0c04f616b6c34496eb2141785b4454 https://justinmeiners.github.io/lc3-vm/