54 lines
985 B
Markdown
54 lines
985 B
Markdown
# 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 offset
|
|
- `+literal`, a numeric value
|
|
- `.pointer`, pointer to a label
|
|
|
|
```
|
|
< comment >
|
|
|
|
+01 < literal >
|
|
|
|
[ 01 02 03 04 ] < block of literals >
|
|
|
|
$01 < pointer8 >
|
|
|
|
{ 01 02 03 04 } < block of pointer8 >
|
|
|
|
~ff0f < pointer16 >
|
|
|
|
( ff00 ff01 ff02 ff03 ) < block of pointer16 >
|
|
|
|
=const +ff
|
|
|
|
:label ADD RTS
|
|
```
|
|
|
|
## TODOs
|
|
|
|
- Implement addressing
|
|
- Implement 16 bits operations
|
|
- Jumps should be relative
|
|
- Catch overflow/underflow
|
|
- Implement literals like `[2]`, and `[ 2 3 ]`.
|
|
- Audo-detect literals length.
|
|
- SDL Layer Emulator
|
|
- Build PPU
|
|
|
|
## 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/ |