2021-01-29 14:17:59 -05:00
|
|
|
# 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
|
|
|
|
|
```
|
2021-01-29 14:35:59 -05:00
|
|
|
|
2021-01-29 20:49:10 -05:00
|
|
|
## Assembly Syntax
|
2021-01-29 14:35:59 -05:00
|
|
|
|
2021-02-04 15:22:08 -05:00
|
|
|
### Write
|
|
|
|
|
|
|
|
|
|
- `;variable`, set a name to address on the zero-page
|
|
|
|
|
- `:label`, set a name to an address
|
|
|
|
|
|
|
|
|
|
### Read
|
|
|
|
|
|
|
|
|
|
- `,literal`, get a literal pointer
|
|
|
|
|
- `.pointer`, get a raw pointer
|
|
|
|
|
|
|
|
|
|
### Special
|
|
|
|
|
|
|
|
|
|
- `@0010`, move to position in the program
|
|
|
|
|
- `( comment )`
|
2021-01-31 00:31:49 -05:00
|
|
|
|
2021-01-29 14:35:59 -05:00
|
|
|
```
|
2021-02-04 21:25:49 -05:00
|
|
|
;value ( alloc a zero-page variable )
|
2021-02-04 15:22:08 -05:00
|
|
|
|
2021-02-04 18:38:04 -05:00
|
|
|
@0010 ( start at page 1 )
|
2021-01-29 20:49:10 -05:00
|
|
|
|
2021-02-04 21:25:49 -05:00
|
|
|
,03 ,02 ADD ,05 EQU
|
|
|
|
|
,there ROT JMC
|
2021-01-30 17:25:48 -05:00
|
|
|
|
2021-02-01 17:49:09 -05:00
|
|
|
:here
|
2021-02-04 18:38:04 -05:00
|
|
|
( when not equal )
|
|
|
|
|
,ee
|
2021-02-01 23:21:27 -05:00
|
|
|
BRK
|
2021-01-30 17:25:48 -05:00
|
|
|
|
2021-02-01 17:49:09 -05:00
|
|
|
:there
|
2021-02-04 18:38:04 -05:00
|
|
|
( when is equal )
|
|
|
|
|
,ff
|
2021-02-01 23:21:27 -05:00
|
|
|
BRK
|
2021-01-29 14:35:59 -05:00
|
|
|
```
|
|
|
|
|
|
2021-02-01 14:58:47 -05:00
|
|
|
## Mission
|
|
|
|
|
|
2021-02-04 00:53:56 -05:00
|
|
|
### Assembler
|
|
|
|
|
|
2021-02-03 14:30:18 -05:00
|
|
|
- Catch overflow/underflow
|
2021-02-04 00:53:56 -05:00
|
|
|
- Constants
|
2021-02-03 14:30:18 -05:00
|
|
|
- Jumps should be relative
|
2021-02-04 00:53:56 -05:00
|
|
|
|
|
|
|
|
### CPU
|
|
|
|
|
|
2021-02-03 14:30:18 -05:00
|
|
|
- Pointers/Literals
|
2021-02-01 17:49:09 -05:00
|
|
|
- A Three-Way Decision Routine(http://www.6502.org/tutorials/compare_instructions.html)
|
2021-02-01 14:58:47 -05:00
|
|
|
- Print word to stdout
|
|
|
|
|
- Draw pixel to screen
|
|
|
|
|
- Detect mouse click
|
2021-01-31 00:31:49 -05:00
|
|
|
- SDL Layer Emulator
|
|
|
|
|
- Build PPU
|
2021-02-04 18:38:04 -05:00
|
|
|
- Add flags..
|
2021-02-01 23:21:27 -05:00
|
|
|
|
2021-01-30 17:25:48 -05:00
|
|
|
## 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/
|
