for pos < 256 {
		indexU64 := pos / 64
		indexBit := pos % 64
		var bitBuf uint64
		if indexBit < 64-w {
			// This window's bits are contained in a single u64
			bitBuf = digits[indexU64] >> indexBit
		} else {
			// Combine the current 64 bits with bits from the next 64
			bitBuf = (digits[indexU64] >> indexBit) | (digits[1+indexU64] << (64 - indexBit))
		}

		// Add carry into the current window