Estimate rows needed for a block that of blake/sha256 maxed out about zkevm-circuits HOT 1 OPEN

// gas cost for allocating num_words on EVM memory
function init_cost(num_words: number) {
  let mem_cost = num_words * 3 + Math.floor(num_words ** 2 / 512);
  let extra_gas = 1 + 2500; // jumpdest + first staticcall
  return mem_cost + extra_gas;
}

// gas cost for executing SHA256 precompile
function exec_cost(num_words: number) {
  let extra_gas = 24;
  return 100 + 60 + num_words * 12 + extra_gas;
}

function find_num_batches(num_words: number, target_gas: number) {
  target_gas -= init_cost(num_words);
  let single_exec_cost = exec_cost(num_words);

  // floor because last batch will fail
  let num_batches = Math.floor(target_gas / single_exec_cost);
  return num_batches;
}

function quantity(num_words: number, num_batches: number) {
  return num_words * num_batches;
}

function find_maxima(target_gas: number) {
  let best_case = {
    num_words: 1,
    num_batches: find_num_batches(1, target_gas),
    get quantity() {
      return quantity(this.num_words, this.num_batches);
    },
  };
  let new_num_words = 1;
  while (1) {
    new_num_words++;
    let new_num_batches = find_num_batches(new_num_words, target_gas);
    let new_quantity = quantity(new_num_words, new_num_batches);
    if (new_quantity > best_case.quantity) {
      best_case.num_batches = new_num_batches;
      best_case.num_words = new_num_words;
      console.log("best case update", best_case);
    }
    // stop once done
    if (new_num_batches === 0) {
      return best_case;
    }
  }
  return best_case;
}

console.log(find_maxima(30_000_000));