2021-01-29 19:17:59 +00:00
|
|
|
# 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 19:35:59 +00:00
|
|
|
|
2021-01-30 01:49:10 +00:00
|
|
|
## Assembly Syntax
|
2021-01-29 19:35:59 +00:00
|
|
|
|
2021-02-04 20:22:08 +00:00
|
|
|
### Write
|
|
|
|
|
|
2021-02-05 18:51:45 +00:00
|
|
|
- `;variable`, set a label to an assigned address
|
|
|
|
|
- `:const`, set a label to a constant short
|
|
|
|
|
- `@label`, set a label to an address
|
2021-02-04 20:22:08 +00:00
|
|
|
|
|
|
|
|
### Read
|
|
|
|
|
|
2021-02-05 18:51:45 +00:00
|
|
|
- `,literal`, push label value to stack
|
|
|
|
|
- `.pointer`, read label value
|
2021-02-04 20:22:08 +00:00
|
|
|
|
|
|
|
|
### Special
|
|
|
|
|
|
2021-02-05 18:51:45 +00:00
|
|
|
- `( comment )`, toggle parsing on/off
|
|
|
|
|
- `|0010`, move to position in the program
|
2021-02-05 19:57:37 +00:00
|
|
|
- `"hello`, push literal bytes for word "hello"
|
2021-01-31 05:31:49 +00:00
|
|
|
|
2021-01-29 19:35:59 +00:00
|
|
|
```
|
2021-02-05 22:01:34 +00:00
|
|
|
( hello world )
|
2021-02-04 20:22:08 +00:00
|
|
|
|
2021-02-05 22:01:34 +00:00
|
|
|
;iterator
|
|
|
|
|
:dev1r FFF0
|
|
|
|
|
:dev1w FFF1
|
2021-01-30 01:49:10 +00:00
|
|
|
|
2021-02-05 22:01:34 +00:00
|
|
|
|0100 @RESET
|
2021-01-30 22:25:48 +00:00
|
|
|
|
2021-02-05 22:01:34 +00:00
|
|
|
"hello
|
|
|
|
|
|
|
|
|
|
@loop
|
|
|
|
|
,dev1w STR
|
|
|
|
|
,iterator LDR
|
|
|
|
|
,01 ADD
|
|
|
|
|
,iterator STR
|
|
|
|
|
,iterator LDR
|
|
|
|
|
,05 NEQ ,loop ROT JSC
|
|
|
|
|
|
|
|
|
|
BRK ( RESET )
|
|
|
|
|
|
|
|
|
|
|c000 @FRAME BRK
|
|
|
|
|
|d000 @ERROR BRK
|
|
|
|
|
|FFFA .RESET .FRAME .ERROR
|
2021-01-30 22:25:48 +00:00
|
|
|
|
2021-01-29 19:35:59 +00:00
|
|
|
```
|
|
|
|
|
|
2021-02-01 19:58:47 +00:00
|
|
|
## Mission
|
|
|
|
|
|
2021-02-04 05:53:56 +00:00
|
|
|
### Assembler
|
|
|
|
|
|
2021-02-03 19:30:18 +00:00
|
|
|
- Catch overflow/underflow
|
|
|
|
|
- Jumps should be relative
|
2021-02-04 05:53:56 +00:00
|
|
|
|
|
|
|
|
### CPU
|
|
|
|
|
|
2021-02-03 19:30:18 +00:00
|
|
|
- Pointers/Literals
|
2021-02-01 22:49:09 +00:00
|
|
|
- A Three-Way Decision Routine(http://www.6502.org/tutorials/compare_instructions.html)
|
2021-02-01 19:58:47 +00:00
|
|
|
- Print word to stdout
|
|
|
|
|
- Draw pixel to screen
|
|
|
|
|
- Detect mouse click
|
2021-01-31 05:31:49 +00:00
|
|
|
- SDL Layer Emulator
|
|
|
|
|
- Build PPU
|
2021-02-04 23:38:04 +00:00
|
|
|
- Add flags..
|
2021-02-02 04:21:27 +00:00
|
|
|
|
2021-02-05 18:51:45 +00:00
|
|
|
### Devices
|
|
|
|
|
|
|
|
|
|
- Devices each have an input byte, an output byte and two request bytes.
|
|
|
|
|
|
2021-01-30 22:25:48 +00:00
|
|
|
## 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/
|
