👋 Welcome to MCAssembly!

This is a very small assembly language for operating scoreboards in Minecraft.

🪛 How to use

There are two ways to provide the source code:

Compiling an Existing File

You can pass a file path as an argument. The command will read, compile, and print the result.

mcasm <path_to_your_file>

Writing Code Interactively

mcasm

If you run mcasm without providing a path, it will:

• Automatically create a temporary file.
• Open this temporary file using your system's default terminal text editor (such as vim or nano).
• Wait for you to write your code.

Once you save and close the editor, it will compile the content of that temporary file and print the result to standard output.

📦 Supported Types

Name	Size	Remarks
byte	1byte
short	2byte
int	4byte	Literal's default.
long	8byte	Able to assign to scoreboards, but it may occurs a overflow.
float	4byte	Can't assign to scoreboards.
double	8byte	Can't assign to scoreboards.

✏️ Syntax

Comment

You can comment out a line adding // to the first of line.

Scoreboard

objective::selector

To reference a scoreboard, it must follow the format above.

Storage

NBTStorage Name

namespace:name

It's easy!

NBT Path

path.to.data[0]::<int>

You can use the same syntax as in Minecraft for the part before the ::.

You can optionally add a type specification, starting with :: and a type name in <>.

It's optional. If you don't add a type specification, it will be treated as int.

🏗️ Mnemonics

Mnemonic	Operands	Remarks
MOV	target: Scoreboard source: (Numeric | Scoreboard)	Copy the right operand's value to the left operand
ADD	target: Scoreboard source: (Numeric | Scoreboard)	Add the right operand's value to the left operand
SUB	target: Scoreboard source: (Numeric | Scoreboard)	Subtract the right operand's value to the left operand
MUL	target: Scoreboard source: (Numeric | Scoreboard)	Multiply the right operand's value to the left operand
DIV	target: Scoreboard source: (Numeric | Scoreboard)	Divide the right operand's value to the left operand
SUR	target: Scoreboard source: (Numeric | Scoreboard)	Modulo the right operand's value to the left operand
NTS	target: Scoreboard source: Storage reference_path: NBTPath magnification: Numeric	Reads a value from the reference_path within the source storage. This value is then multiplied by magnification and stored in the target scoreboard.
STN	target: Storage target_path: NBTPath source: Scoreboard magnification: Numeric	Copies the value from the source scoreboard, multiplies it by magnification, and stores the result in the target_path of the target storage.
REL	target: Scoreboard	Resets the score for the player specified in the target scoreboard. This removes that player's entry from the objective. (Equivalent to /scoreboard players reset)

📄 Sample Codes

1. Calcation between Scores

Setup:

scoreboard objective add mcasm dummy

MCAssembly:

// B, C = 5, 6
MOV mcasm::#B 5
MOV mcasm::#C 6

// A = (B + C) * 3
MOV mcasm::#A mcasm::#B
ADD mcasm::#A mcasm::#C
MUL mcasm::#A 3

Result:

scoreboard players set #B mcasm 5
scoreboard players set #C mcasm 6
scoreboard players operation #A mcasm = #B mcasm
scoreboard players operation #A mcasm += #C mcasm
scoreboard players set LITERAL_SCORE_CONVERSION MC_ASM 3
scoreboard players operation #A mcasm *= LITERAL_SCORE_CONVERSION MC_ASM

2. Multiply Storage

Setup:

scoreboard objective add mcasm dummy
data merge storage mcasm:foo {foo: {bar: {buz: 3.14}}}

MCAssembly:

// Move the value to a
// temp scoreboard for calcation
NTS mcasm::#temp mcasm:foo foo.bar.buz::<float> 1000
// Make value 2x
MUL mcasm::#temp 2
// Store result
STN mcasm:foo foo.bar.buz::<float> mcasm::#temp 0.001

Result:

execute store result score #temp mcasm run data get mcasm:foo foo.bar.buz 1000
scoreboard players set LITERAL_SCORE_CONVERSION MC_ASM 2
scoreboard players operation #temp mcasm *= LITERAL_SCORE_CONVERSION MC_ASM
execute store result storage mcasm:foo foo.bar.buz float 0.001 run scoreboard players get #temp mcasm