Method Search

ethereum/ethash/ethash.go:429–477

(block pow.Block, stop <-chan struct{}, index int)

}

func (pow *Full) Search(block pow.Block, stop <-chan struct{}, index int) (nonce uint64, mixDigest []byte) {
	dag := pow.getDAG(block.NumberU64())

	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	diff := block.Difficulty()

	i := int64(0)
	starti := i
	start := time.Now().UnixNano()
	previousHashrate := int32(0)

	nonce = uint64(r.Int63())
	hash := hashToH256(block.HashNoNonce())
	target := new(big.Int).Div(maxUint256, diff)
	for {
		select {
		case <-stop:
			atomic.AddInt32(&pow.hashRate, -previousHashrate)
			return 0, nil
		default:
			i++

			// we don't have to update hash rate on every nonce, so update after
			// first nonce check and then after 2^X nonces
			if i == 2 || ((i % (1 << 16)) == 0) {
				elapsed := time.Now().UnixNano() - start
				hashes := (float64(1e9) / float64(elapsed)) * float64(i-starti)
				hashrateDiff := int32(hashes) - previousHashrate
				previousHashrate = int32(hashes)
				atomic.AddInt32(&pow.hashRate, hashrateDiff)
			}

			ret := C.ethash_full_compute(dag.ptr, hash, C.uint64_t(nonce))
			result := h256ToHash(ret.result).Big()

			// TODO: disagrees with the spec https://gopkg.in/ethereum/wiki/wiki/Ethash#mining
			if ret.success && result.Cmp(target) <= 0 {
				mixDigest = C.GoBytes(unsafe.Pointer(&ret.mix_hash), C.int(32))
				atomic.AddInt32(&pow.hashRate, -previousHashrate)
				return nonce, mixDigest
			}
			nonce += 1
		}

		if !pow.turbo {
			time.Sleep(20 * time.Microsecond)
		}
	}
}

func (pow *Full) GetHashrate() int64 {
	return int64(atomic.LoadInt32(&pow.hashRate))