www.mikescher.com/www/statics/aoc/2019/05_solution-1.ts

namespace AdventOfCode2019_05_1
{
	const DAY     = 5;
	const PROBLEM = 1;

	export async function run()
	{
		let input = await AdventOfCode.getInput(DAY);
		if (input == null) return;

		let runner = new Interpreter(input.split(",").map(p => parseInt(p.trim())), [1]);

		runner.run();

        AdventOfCode.output(DAY, PROBLEM, runner.output.reverse()[0].toString());
	}

	class Interpreter
	{
		program: number[];
		input: number[];
		instructionpointer: number;
		inputpointer: number;
		output: number[];

		constructor(prog: number[], input: number[])
		{
			this.program = prog;
			this.input = input;
			this.instructionpointer = 0;
			this.inputpointer = 0;
			this.output = [];
		}

		run()
		{
			while(true)
			{
				const cmd = new Op(this.program[this.instructionpointer]);
				if (cmd.opcode == OpCode.ADD)
				{
					const p0 = cmd.getParameter(this, 0);
					const p1 = cmd.getParameter(this, 1);
					const pv = p0 + p1;
					cmd.setParameter(this, 2, pv);
				}
				else if (cmd.opcode == OpCode.MUL)
				{
					const p0 = cmd.getParameter(this, 0);
					const p1 = cmd.getParameter(this, 1);
					const pv = p0 * p1;
					cmd.setParameter(this, 2, pv);
				}
				else if (cmd.opcode == OpCode.HALT)
				{
					return;
				}
				else if (cmd.opcode == OpCode.IN)
				{
					const pv = this.input[this.inputpointer];
					cmd.setParameter(this, 0, pv);
					this.inputpointer++;
				}
				else if (cmd.opcode == OpCode.OUT)
				{
					const p0 = cmd.getParameter(this, 0);
					this.output.push(p0);
					AdventOfCode.outputConsole("# " + p0);
				}
				else throw "Unknown Op: " + cmd.opcode + " @ " + this.instructionpointer;

				this.instructionpointer += 1 + cmd.parametercount;
			}
		}
	}

	enum OpCode 
	{
		ADD  = 1,
		MUL  = 2,
		IN   = 3,
		OUT  = 4,
		HALT = 99,
	}

	enum ParamMode
	{
		POSITION_MODE  = 0,
		IMMEDIATE_MODE = 1,
	}

	class Op
	{
		opcode: OpCode;
		modes: ParamMode[];

		name: string;
		parametercount: number;

		constructor(v: number)
		{
			this.opcode = v%100;
			v = Math.floor(v/100);
			this.modes = [];
			for(let i=0; i<4; i++) 
			{
				this.modes.push(v%10);
				v = Math.floor(v/10);
			}

			     if (this.opcode == OpCode.ADD)  { this.name="ADD";  this.parametercount=3; }
			else if (this.opcode == OpCode.MUL)  { this.name="MUL";  this.parametercount=3; }
			else if (this.opcode == OpCode.HALT) { this.name="HALT"; this.parametercount=0; }
			else if (this.opcode == OpCode.IN)   { this.name="IN";   this.parametercount=1; }
			else if (this.opcode == OpCode.OUT)  { this.name="OUT";  this.parametercount=1; }
			else throw "Unknown opcode: "+this.opcode;
		}

		getParameter(proc: Interpreter, index: number): number
		{
			const prog = proc.program;
			const ip   = proc.instructionpointer;

			let p = prog[ip+1+index];

				 if (this.modes[index] == ParamMode.POSITION_MODE)  p = prog[p];
			else if (this.modes[index] == ParamMode.IMMEDIATE_MODE) p = p;
			else throw "Unknown ParamMode: "+this.modes[index];

			return p;
		}

		setParameter(proc: Interpreter, index: number, value: number): void
		{
			const prog = proc.program;
			const ip   = proc.instructionpointer;

			let p = prog[ip+1+index];

				 if (this.modes[index] == ParamMode.POSITION_MODE)  prog[p] = value;
			else if (this.modes[index] == ParamMode.IMMEDIATE_MODE) throw "Immediate mode not allowed in write";
			else throw "Unknown ParamMpde: "+this.modes[index];
		}
	}
}