MARIE Instruction Set (with Opcodes)

In MARIE, each instruction is 16 bits long with the first 4 bits representing the opcode and the remaining 12 bits are being used to represent the address.

For example the instruction CLEAR, the Opcode is A in HEX and 1010 in binary so the instruction will look something like `1010............`

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Code Table

Type	Instruction	Hex Opcode	Summary
Arithmetic	Add X	3	Adds value in AC at address X into AC, AC ← AC + M[X]
	Subt X	4	Subtracts value in AC at address X into AC, AC ← AC - M[X]
	AddI X	B	Add Indirect: Use the value at X as the actual address of the data operand to add to AC
Data Transfer	Load X	1	Loads Contents of Address X into AC
	LoadImmi X	A	Load Immediate: Load the 12-bit unsigned value X into the AC, AC ← X
	Clear		Alias for LoadImmi 0, AC ← 0
	Store X	2	Stores Contents of AC into Address X
I/O	Input	5	Request user to input a value
	Output	6	Prints value from AC
Branch	Jump X	9	Jumps to Address X
	Skipcond (C)	8	Skips the next instruction based on C: if (C) = - 000: Skips if AC < 0 - 400: Skips if AC = 0 - 800: Skips if AC > 0 - 0C00: Skips if AC ≠ 0
Subroutine	JnS X	0	Jumps and Store: Stores value of PC at address X then jumps to X+1
	JumpI X	C	Uses the value at X as the address to jump to
Indirect Addressing	LoadI	D	Loads value from indirect address into AC e.g. LoadI addresspointer Gets address value from addresspointer, loads value at the address into AC
	StoreI	E	Stores value in AC at the indirect address. e.g. StoreI addresspointer Gets value from addresspointer, stores the AC value into the address
	Halt	7	End the program