Tile

Tile is a two-dimensional non-textual language made by User:Dtp09. Tile programs consist of a rectangular grid of "tiles", with each tile being either completely white ("empty") or containing four smaller black or white squares, referred to as "subtiles", to represent four bits of data. The data in the tiles represent instructions and other data that can be executed as the program runs.

The program counter is represented as a position on the grid, which travels in a certain direction, executing any tile it lands on as an instruction. The program counter then turns to the left, right, or goes straight, depending on the circumstances, then executes the next instruction. Programs can be thought of as a sort of path that the PC traverses, executing instruction as it moves through the path.

Specifications

Tile uses unsigned 8-bit integers. It uses an unlimited length stack, 64kb memory, an ASCII input that can be read up to 2^16 characters, and an unlimited ASCII output.

Tiles

Below is a list of every combination that a tile on the grid could have. Stack values will be referred to as s1, s2, and s3, representing the top stack value, 2nd top stack value, and 3rd top stack value respectively. If there is no value in the given stack position, it will assume 0.

[s2][s1] represents a 16 bit value, with s2 as the high byte and s1 as the low byte.

Tile	Name	Description
	Empty	Negative space, the PC cannot enter or turn here without terminating the program.
`░░`	No-op	No operation. Mostly used for routing a path for the program counter.
`░▄`	Write	Writes s3 to memory location [s2][s1].
`▄░`	Subtract	Pops s1 and s2, pushes s2 - s1.
`▄▄`	Jump	The program counter will move twice in a straight line no matter what. Useful for entering loops, joining two paths, etc.
`░▀`	Read	Pops s1 and s2, pushes value from memory location [s2][s1] to the stack.
`░█`	Input	Pushes the ASCII code of an input character in an index determined by 16-bit value [s2][s1].
`▄▀`	Multiply	Pops s1 and s2, pushes s2 * s1.
`▄█`	Greater	If s2 > s1, turn PC right. Else, turn PC left.
`▀░`	Push	Push an 8-bit value to the stack, using the relative sides of the tile as binary data. (more below)
`▀▄`	Random	Program counter randomly chooses one of up to three possible directions to turn that isn't an empty tile.
`█░`	Add	Pops s1 and s2, pushes s2 + s1.
`█▄`	Less	If s2 < s1, turn PC right. Else, turn PC left.
`▀▀`	Output	Outputs s1 as an ASCII charater then pops it.
`▀█`	Equals	If s2 == s1, turn PC right. Else, turn PC left.
`█▀`	Divide	Pops s1 and s2, pushes quotient of s2 / s1, then pushes remainder.
`██`	Start/Debug	This is where the program counter will start. During execution, it will act as a debug, printing exection info to the JS console.

Additional info

Which Tile is the Start Tile?

You can have multiple start tiles (██) in a single program. As only one tile can be the PC's initial value, it is decided as the tile furthest to the left, then the tile furthest up.

Push

The Push instruction (▀░) reads a byte of binary data from the tiles to the sides relative to the direction the PC is moving in. Binary data is read with the uppermost/leftmost tile as the upper four bits, and the bottommost/rightmost tile as the lower four bits. If there is only one (non-empty) tile on the relative side of the Push tile, it will assume a byte with the upper four bits unset. A push command with only empty tiles to its relative side will push 0.

Push commands force the PC to move straight, and cannot turn left or right.

Execution End

Execution will end if any of the following happens:

Program counter has too many possible places it can go: for instance, if the PC is on a NOP tile and the path can lead it either left or right, it wont choose one and instead terminate the program. Some instruction (push, less/greater/equal, random) have special rules for where the PC will go after execution and aren't affected by this rule.
Division by 0
Attempt to move program counter out of bounds
Attempt to move program counter onto an empty tile

Why are your programs padded with empty tiles?

It looks nicer but its not required

Interpreter

An interpreter was written in HTML+Javascript also by User:Dtp09

Update Log

The interpreter update log is located at Tile/Update Log

Tile

Contents

Specifications

Tiles