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Mirror of https://git.sr.ht/~rabbits/uxn
etc | ||
examples | ||
.clang-format | ||
.gitignore | ||
assembler.c | ||
build.sh | ||
cli.c | ||
emulator.c | ||
LICENSE | ||
README.md | ||
uxn.c | ||
uxn.h |
Uxn
A stack-based VM, written in ANSI C.
Assembly Syntax
Write
;variable
, automatically assign an address to a label.:const FFCF
, manually assign an address to a label.@label
, assign the current address to a label.
Read
,literal
, push label value to stack, prefixed withLIT LEN
..pointer
, push label value to stack.
Special
( comment )
, toggle parsing on/off.|0010
, move to position in the program."hello
, push literal bytes for word "hello".#04
, a zero-page address, equivalent to,0004
.
Operator modes
,1234 ,0001 ADD^
, 16-bits operators have the short flag^
.,12 ,11 GTH JMP?
, conditional operators have the cond flag?
.
( hello world )
;iterator
|0100 @RESET
@word1 "hello_world ( len: 0x0b )
@loop
,00 IOW ( write to device#0 )
,incr JSR ( increment itr )
,word1 ,strlen JSR ( get strlen )
NEQ ,loop ROT JSR? ( loop != strlen )
BRK
@strlen
,0001 ADD^ LDR
RTS
@incr
,iterator LDR
,01 ADD
,iterator STR
,iterator LDR
RTS
|c000 @FRAME BRK
|d000 @ERROR BRK
|FFFA .RESET .FRAME .ERROR
TODOs
- Implement signed flag to operators.
- On-screen debugger.
- Auto-advance ldr?
- Getting rid of IOR/IOW would be nice..
- Sending from the wst to the rst, balance mode/flag?
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/