===== ISTEM =====
Solve the following programming task.

TASK: TIK Register Machine

Write a function 'runTik(program)' that runs a program written in TIK, a small made-up language, and returns an array of the numbers it outputs.

Program text:
- Instructions are separated by newlines. Leading and trailing spaces on a line are ignored.
- Lines that are empty (or only spaces) and lines whose first non-space character is '#' are ignored and are not instructions.
- Within an instruction, tokens are separated by one or more spaces.

Machine:
- There are four registers named a, b, c and d. All start at 0.
- Every value stored in a register is reduced to the range 0..999 by taking it modulo 1000, always giving a non-negative result (for example -1 becomes 999 and 1003 becomes 3).
- An integer literal is an optional '-' followed by one or more digits ('+5' and '5.0' are not valid).
- An operand written as X below is either a register name or an integer literal. Its value is the register's value, or the literal reduced to 0..999 in the same way.

Instructions (R must be a register name, N must be an integer literal):
- set R X: R becomes the value of X.
- add R X: R becomes R plus the value of X.
- mul R X: R becomes R times the value of X.
- out X: appends the value of X to the output.
- jmp X N: if the value of X is not 0, the next instruction is the one N instructions away from this one (N may be negative; ignored lines are not counted). Otherwise execution continues with the next instruction.
Instruction names and register names are lowercase; anything else is invalid.

Running:
- Before running anything, check the whole program. If any line that is not ignored is not a valid instruction (unknown name, wrong number of operands, or an invalid register, literal or operand), throw an Error whose message is 'bad instruction at line K', where K is the 1-based line number of the first such line in the original text, counting ignored lines too. In that case nothing is run.
- Execution starts at the first instruction and stops normally when the next instruction position is before the first instruction or after the last one.
- A program may execute at most 10,000 instructions. If it has not stopped after executing 10,000 instructions, throw an Error with the message 'step limit'.

STARTER CODE (javascript):
function runTik(program) {
  // Write your code here
}

module.exports = { runTik };


RULES:
- Keep the function name and signature EXACTLY as given.
- Return working code only. No explanations.
- Put the code in a single ``` block.
- Try to solve it first. If you genuinely cannot, write only this single
  line instead of producing faulty code: CANNOT_SOLVE

===== HAM YANIT =====
```javascript
function runTik(program) {
  const lines = program.split('\n');
  const instructions = [];

  const isReg = (t) => /^[abcd]$/.test(t);
  const isLit = (t) => /^-?\d+$/.test(t);
  const literalValue = (n) => ((n % 1000) + 1000) % 1000;

  const parseOperand = (token) => {
    if (isReg(token)) return { kind: 'reg', name: token };
    if (isLit(token)) return { kind: 'lit', num: parseInt(token, 10) };
    return null;
  };

  for (let i = 0; i < lines.length; i++) {
    const raw = lines[i];
    const trimmed = raw.trim();
    if (trimmed === '' || trimmed[0] === '#') continue; // ignored line

    const lineNum = i + 1;
    const tokens = trimmed.split(/\s+/);
    const name = tokens[0];

    const makeError = () => { throw new Error(`bad instruction at line ${lineNum}`); };

    if (name === 'set' || name === 'add' || name === 'mul') {
      if (tokens.length !== 3) makeError();
      const R = tokens[1];
      if (!isReg(R)) makeError();
      const X = parseOperand(tokens[2]);
      if (!X) makeError();
      instructions.push({ type: name, R, X, line: lineNum });
    } else if (name === 'out') {
      if (tokens.length !== 2) makeError();
      const X = parseOperand(tokens[1]);
      if (!X) makeError();
      instructions.push({ type: name, X, line: lineNum });
    } else if (name === 'jmp') {
      if (tokens.length !== 3) makeError();
      const X = parseOperand(tokens[1]);
      if (!X) makeError();
      const Ntoken = tokens[2];
      if (!isLit(Ntoken)) makeError();
      const N = parseInt(Ntoken, 10);
      instructions.push({ type: name, X, N, line: lineNum });
    } else {
      makeError();
    }
  }

  const regs = { a: 0, b: 0, c: 0, d: 0 };
  const getValue = (op) => {
    if (op.kind === 'reg') return regs[op.name];
    return literalValue(op.num);
  };

  const output = [];
  let ip = 0;
  let steps = 0;

  while (ip >= 0 && ip < instructions.length) {
    if (steps >= 10000) throw new Error('step limit');
    steps++;

    const instr = instructions[ip];
    switch (instr.type) {
      case 'set': {
        const v = getValue(instr.X);
        regs[instr.R] = v;
        ip++;
        break;
      }
      case 'add': {
        const v = getValue(instr.X);
        regs[instr.R] = (regs[instr.R] + v) % 1000;
        ip++;
        break;
      }
      case 'mul': {
        const v = getValue(instr.X);
        regs[instr.R] = (regs[instr.R] * v) % 1000;
        ip++;
        break;
      }
      case 'out': {
        output.push(getValue(instr.X));
        ip++;
        break;
      }
      case 'jmp': {
        const cond = getValue(instr.X);
        if (cond !== 0) {
          const offset = literalValue(instr.N);
          ip = ip + offset;
        } else {
          ip++;
        }
        break;
      }
    }
  }

  return output;
}

module.exports = { runTik };
```