scripting.md

Scripting

To program the computer, I created a basic language named MCASM (Minecraft Assembly).

If you wish to script, you can find the Sublime Text package enabling syntax highlighting and compiling.

The syntax is pretty straightforward. Each line contains a opcode (see the list below) followed by the necessary arguments.

Arguments may be integers or references to other lines (see named-lines).

There can be any number of blank lines and comments

For example:

LOAD R2 11  // Loads address 11 into register 2

To compile your MCASM script, run the converter script and place the resulting .mcfunction file in the programs folder.

Alternatively, if you are using the Sublime Text package, you can run the command "Build With: mcasm", then put the .mcfunction file the folder.

Comments

You can write one-line or multi-line comments using the standard // and /* */ syntax.

For example:

OUT R1  // This is a comment
/*
    This is also a comment
*/

Named lines

To simplify and avoid managing addresses, you can optionally named certain lines and reference them in other instructions.

To name a line, write #the-name# anywhere on the line (preferably at the beginning or end). Referencing it in an instruction is then as simple as writing the name for the argument.

For example:

#my-value# 42
LOAD R1 my-value  // Loads the value 42 into register 1

Instructions

Here is the complete list of available instructions with their arguments and what they do.

Opcode	Argument	Result
LOAD R1	Source address	Loads the value at the source address into register 1
STORE R1	Destination address	Stores the value of register 1 in the destination address
JUMP IF R1	Jump address	Jumps to the given address if register 1 equals 0
ADD R1	Value address	Adds the value at the given address to register 1
<< R1	-	Bitshifts register 1 once to the left (= multiplies by 2)
NOT R1	-	Inverts register 1 (= performs the bitwise NOT operation)
JUMP	Jump address	Jumps to the given address
STOP	-	Stops the execution of the script
LOAD R2	Source address	Loads the value at the source address into register 2
STORE R2	Destination address	Stores the value of register 2 in the destination address
JUMP IF R2	Jump address	Jumps to the given address if register 2 equals 0
ADD R2	Value address	Adds the value at the given address to register 2
<< R2	-	Bitshifts register 2 once to the left (= multiplies by 2)
NOT R2	-	Inverts register 2 (= performs the bitwise NOT operation)
OUT R1	-	Outputs the value of register 1
OUT R2	-	Outputs the value of register 2
LOAD R1 ADDR R2	-	Loads the value at the address stored in register 2 into register 1
STORE R1 ADDR R2	-	Stores the value of register 1 into the address stored in register 2
BEQ	Branch address	Branches to the given address if register 1 and 2 are equal
SUB R1	Value address	Subtracts the value at the given address from register 1
>> R1	-	Bitshifts register 1 once to the right (= divides by 2)
BGT	Branch address	Branches to the given address if register 1 is greater than register 2
BLT	Branch address	Branches to the given address if register 1 is less than register 2
BRANCH	Branch address	Branches to the given address
LOAD R2 ADDR R1	-	Loads the value at the address stored in register 1 into register 2
STORE R2 ADDR R1	-	Stores the value of register 2 into the address stored in register 1
JEQ	Jump address	Jumps to the given address if register 1 and 2 are equal
SUB R2	Value address	Subtracts the value at the given address from register 2
>> R2	-	Bitshifts register 2 once to the right (= divides by 2)
JGT	Jump address	Jumps to the given address if register 1 is greater than register 2
JLT	Jump address	Jumps to the given address if register 1 is less than register 2
RBR	-	Returns to the branch address (only the last branch address is stored, meaning only chained branches are not reversible)
MUL R1	Value address	Multiplies register 1 by the value at the given address
DIV R1	Value address	Divides register 1 by the value at the given address
MUL R2	Value address	Multiplies register 2 by the value at the given address
DIV R2	Value address	Divides register 2 by the value at the given address