difficulty calculation, move from randomx to autolykos2

include/constants.h

@@ -8,8 +8,29 @@
 #define DECIMALS 1000000000000ULL
 #define DIFFICULTY_ADJUSTMENT_INTERVAL 960 // Every 960 blocks (roughly every 24 hours with a 90 second block time)
                                            // Max adjustment per is x2. So if blocks are coming in too fast, the difficulty will at most double every 24 hours, and vice versa if they're coming in too slow.
-#define RANDOMX_KEY_ROTATION_INTERVAL 6720 // 1 week at 90s block time
 #define TARGET_BLOCK_TIME 90 // Target block time in seconds
+#define INITIAL_DIFFICULTY 0x1f0c1422 // Default compact target used by Autolykos2 PoW (This is ridiculously low)
+//#define INITIAL_DIFFICULTY 0x1d1b7c51 // This takes 90s on my machine with a single thread, good for testing
+
+// Future Autolykos2 constants:
+#define EPOCH_LENGTH 350000 // ~1 year at 90s
+#define BASE_DAG_SIZE (2ULL << 30) // 2 GB
+#define DAG_BASE_GROWTH (1ULL << 30) // 1 GB, calculated fully later
+#define DAG_BASE_CAP (8ULL << 30) // 8 GB, adjusted per cycle based off DAG_BASE_GROWTH
+// Swings - calculated as MIN(percentage, absolute GB) to prevent absurd swings from low hashrate or very large DAG growth
+#define DAG_MAX_UP_SWING_PERCENTAGE 1.3 // 30%
+#define DAG_MAX_DOWN_SWING_PERCENTAGE 0.85 // 15%
+#define DAG_MAX_UP_SWING_GB (4ULL << 30) // 4 GB
+#define DAG_MAX_DOWN_SWING_GB (1ULL << 30) // 1 GB
+#define KICKOUT_TARGET_PERCENTAGE 75
+#define KICKOUT_TARGET_BLOCK 30000 // 1 month at 90s block time
+
+/**
+ * Each epoch has 2 phases, connected logarithmically:
+ * - Phase 1: Aggressive DAG growth (target is ~75% of the max cap) to kick out any ASICs, 30k blocks (roughly 1 month)
+ * - Phase 2: Stable DAG growth (target is the max cap) to provide a stable environment for GPU miners, 320k blocks (roughly 11 months)
+**/
+
 static const uint64_t M_CAP = 18446744073709551615ULL; // Max uint64
 static const uint64_t TAIL_EMISSION = DECIMALS; // Emission floor is 1.0 coins per block
 // No max supply. Instead of halving, it'll follow a more gradual, Monero-like emission curve.