Uxn is a 8-bit virtual stack machine with 32 instructions.
Uxn is a portable 8-bit virtual computer inspired by forth-machines, capable of running simple tools and games programmable in its own esoteric assembly language.
It was designed with an implementation-first mindset with the goal of targeting salvaged computers, the distribution of Uxn projects is akin to sharing game roms for any classic console emulator.
Memory
| Stacks | Working Stack | Pointer | 1 byte |
|---|---|---|---|
| Data | 256 bytes | ||
| Return Stack | Pointer | 1 byte | |
| Data | 256 bytes | ||
| Memory | RAM | Pointer | 1 short |
| Data | 64kb |
The CPU can tunnel through 128 subroutines and find its way back with the return stack, the JSR opcode jumps while pushing a return address to the return-stack, the opcode to return from a subroutine is JMPr. An item on the work stack can be sent to the return stack with STH(stash) and returned with STHr. To learn more, see the Uxntal documentation.
uxntal
Uxntal is the programming language for the Uxn stack-machine.
The programming language for creating Uxn-compatible applications is called Uxntal or simply Tal, it is a unique flavor of assembly designed for this unique stack-machine. The program that tranforms Tal files, into Uxn-compatible roms, is the Uxn Assembler(uxnasm).
Stack machine programming might look at bit odd, as it uses a postfix notation, which means that operators are always found at the end of an operation. For instance, one would write 3 4 + instead of 3 + 4. The expression written (5 + 10) * 3 in conventional notation would be written 3 10 5 + * in reverse Polish notation.
uxnemu
Uxnemu is a Uxn emulator written in ANSI C, and SDL2.
The thin layer that is the Uxn emulator is the only part of this project needing to be ported to make the system available on a new platform. For that reason, Uxn was designed with a focus on portability and simplicity such that it welcomes anyone to try their hand at building their own implementation. The current emulator is 400 lines of C89, with SDL2 as its only dependecy.
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Last update on 15K02, edited 23 times. +84/139fh ----||