Merge pull request #237

41a95e7 add comment about avoiding overflow (smooth)
754a785 minimum subsidy for mining incentives, remove unused LEGACY_FEE define (smooth)
This commit is contained in:
Riccardo Spagni 2015-03-05 10:56:46 +02:00
commit 8237705964
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3 changed files with 13 additions and 4 deletions

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@ -51,6 +51,7 @@
// MONEY_SUPPLY - total number coins to be generated
#define MONEY_SUPPLY ((uint64_t)(-1))
#define EMISSION_SPEED_FACTOR (20)
#define FINAL_SUBSIDY_PER_MINUTE ((uint64_t)300000000000) // 3 * pow(10, 11)
#define CRYPTONOTE_REWARD_BLOCKS_WINDOW 100
#define CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE 20000 //size of block (bytes) after which reward for block calculated using block size
@ -61,9 +62,6 @@
#define FEE_PER_KB ((uint64_t)10000000000) // pow(10, 10)
// temporarily to allow backward compatibility during the switch to per-kb
//#define MINING_ALLOWED_LEGACY_FEE ((uint64_t)100000000000) // pow(10, 11)
#define ORPHANED_BLOCKS_MAX_COUNT 100

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@ -1709,7 +1709,14 @@ bool blockchain_storage::handle_block_to_main_chain(const block& bl, const crypt
bei.bl = bl;
bei.block_cumulative_size = cumulative_block_size;
bei.cumulative_difficulty = current_diffic;
bei.already_generated_coins = already_generated_coins + base_reward;
// In the "tail" state when the minimum subsidy (implemented in get_block_reward) is in effect, the number of
// coins will eventually exceed MONEY_SUPPLY and overflow a uint64. To prevent overflow, cap already_generated_coins
// at MONEY_SUPPLY. already_generated_coins is only used to compute the block subsidy and MONEY_SUPPLY yields a
// subsidy of 0 under the base formula and therefore the minimum subsidy >0 in the tail state.
bei.already_generated_coins = base_reward < (MONEY_SUPPLY-already_generated_coins) ? already_generated_coins + base_reward : MONEY_SUPPLY;
if(m_blocks.size())
bei.cumulative_difficulty += m_blocks.back().cumulative_difficulty;

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@ -60,6 +60,10 @@ namespace cryptonote {
//-----------------------------------------------------------------------------------------------
bool get_block_reward(size_t median_size, size_t current_block_size, uint64_t already_generated_coins, uint64_t &reward) {
uint64_t base_reward = (MONEY_SUPPLY - already_generated_coins) >> EMISSION_SPEED_FACTOR;
if (base_reward < FINAL_SUBSIDY_PER_MINUTE)
{
base_reward = FINAL_SUBSIDY_PER_MINUTE;
}
//make it soft
if (median_size < CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE) {