# Uxn
A [stack-based VM](https://wiki.xxiivv.com/site/uxn.html), written in ANSI C.
## Build
To build the Uxn emulator, you must have [SDL2](https://wiki.libsdl.org/).
```sh
./build.sh
--debug # Add debug flags to compiler
--cli # Run rom without graphics
```
## Emulator Controls
- `ctrl+h` toggle debugger
- `alt+h` toggle zoom
## Uxambly
Read more in the [Uxambly Guide](https://wiki.xxiivv.com/site/uxambly.html).
```
%RTN { JMP2r }
( devices )
|0100 ;Console { pad 8 char 1 byte 1 short 2 }
|0200 ^RESET JMP
|0204 ,ERROR JMP2
|0208 ,FRAME JMP2
( program )
@RESET
,text1 ,print-label JSR2
,text2 ,print-label JSR2
#ab =Console.byte
#cdef =Console.short
BRK
@print-label ( text )
$loop
( send ) DUP2 PEK2 =Console.char
( incr ) #0001 ADD2
( loop ) DUP2 PEK2 #00 NEQ ^$loop JNZ
POP2
RTN
@text1 [ Welcome 20 to 20 UxnVM 0a00 ]
@text2 [ Hello 20 World 0a00 ]
@FRAME BRK
@ERROR BRK
```
## TODOs
- Shortcut to export/import disk state
- Implement Uxambly REPL
- Load disks at a different place than 0x0000.
## Palettes
- `[ 6a03 4a0d aa0c ]`, purple/cyan
- `[ a1f3 a14d a16c ]`, grey-pink/teal
## 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/