GB Instructions JSON to Go maps

instructions.js

const { unprefixed, cbprefixed } = require("./Opcodes.json");

const opToCode = (mnemonic, op) => {
  const name = op.name.toUpperCase();

  // for hex used in RST
  if (mnemonic === "RST" && name.endsWith("H")) {
    return `Byte(0x${name.slice(0, -1)})`;
  }

  // special case since we have conditional 'C' and register 'C'
  if (mnemonic === "JP" && name === "C") {
    return "Ca";
  }

  if (!isNaN(parseInt(name))) {
    return `Byte(${name})`;
  }

  return name;
};

const generate = (instructions) =>
  Object.entries(instructions)
    .map(([key, val]) => {
      let operands = "nil";
      if (val.operands.length) {
        const ops =
          val.operands
            .map((op) => {
              let struct = `{Symbol: ${opToCode(val.mnemonic, op)}`;
              if (op.increment) {
                struct += ", Inc: true";
              }
              if (op.decrement) {
                struct += ", Dec: true";
              }
              if (!op.immediate) {
                struct += ", Deref: true";
              }
              return struct + "}";
            })
            .join(",\n        ") + ",";
        operands = `[]Operand{
        ${ops}
      }`;
      }

      return `
    ${key}: {
      ${val.mnemonic},
      ${operands},
      []int{${val.cycles.join(", ")}},
    },`;
    })
    .join("");

console.log(`var unprefixed = map[byte]Instruction{${generate(unprefixed)}\n}\n`);
console.log(`var cbprefixed = map[byte]Instruction{${generate(cbprefixed)}\n}`);