def header_to_words(header): """Convert 80-byte header into 16 uint32 words (first 448 bits = 14 words) for kernel""" words = list(unpack("<16I", header.ljust(64, b'\x00'))) return words[:14] # first 14 words (nonce is word 14 in kernel) Main miner ------------------------------ class SHA256GPUMiner: def init (self, device_id=0): platforms = cl.get_platforms() if not platforms: raise RuntimeError("No OpenCL platforms found")
# Target: first 4 bytes must be <= 0x0000ffff (very easy) # For difficulty 1, target = 0x00000000ffff000000... easy_target = "0000ffff" + "00"*28
data[14] = nonce; data[15] = 0x80000000; // padding (bit 1, then zeros) sha256 gpu miner
// Check if solution (big-endian compare with target) // We just check first 32 bits (hash2[0] byteswapped to big-endian) uint be_hash0 = ((hash2[0] >> 24) & 0xFF) """ Helper: prepare block header (Bitcoin-style, 80 bytes) ------------------------------ def make_block_header(version, prev_hash, merkle_root, timestamp, bits, nonce=0): """Pack 80-byte Bitcoin block header (little-endian for each field except nonce)""" header = (pack("<I", version) + pack("<32s", bytes.fromhex(prev_hash)[::-1]) + pack("<32s", bytes.fromhex(merkle_root)[::-1]) + pack("<I", timestamp) + pack("<I", bits) + pack("<I", nonce)) return header
# Mine with small nonce range for demo nonce = miner.mine(dummy_header, easy_target, start_nonce=0, nonce_range=1000000, work_size=65536) data[15] = 0x80000000
for (i = 0; i < 16; i++) W[i] = data[i];
// First 64-byte block (exactly 512 bits) sha256_transform(data, hash); // padding (bit 1
dummy_header = ( "01000000" + # version "0000000000000000000000000000000000000000000000000000000000000000" + # prev hash "3ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4a" + # merkle root (coinbase) "29ab5f49" + # timestamp (2017-ish) "ffff001d" + # bits (very low difficulty) "00000000" # nonce (zero) )
// Copy fixed block words (0..13) and add nonce at word 14 uint data[16]; for (int i = 0; i < 14; i++) data[i] = fixed_block[i];
__kernel void mine(__global const uint *fixed_block, // first 14 words (448 bits) __global uint *results, // nonce, hash0, hash1 (or zeros) const uint start_nonce, const uint target_high) // target for hash[0] (MSW)
void sha256_transform(const uint *data, uint *hash) uint W[64]; uint i, t1, t2; uint a, b, c, d, e, f, g, h;