PaperMC/paper-server/patches/features/0013-Optimize-Bit-Operations-by-inlining.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 4 Jun 2020 02:24:49 -0400
Subject: [PATCH] Optimize Bit Operations by inlining

Inline bit operations and reduce instruction count to make these hot
operations faster

diff --git a/net/minecraft/core/BlockPos.java b/net/minecraft/core/BlockPos.java
index 98f0b1cf19d7a035849a9a2fa25e2be3a4c5a980..a81694a22e94cca6f7110f7d5b205d1303f4e071 100644
--- a/net/minecraft/core/BlockPos.java
+++ b/net/minecraft/core/BlockPos.java
@@ -51,15 +51,17 @@ public class BlockPos extends Vec3i {
     };
     private static final Logger LOGGER = LogUtils.getLogger();
     public static final BlockPos ZERO = new BlockPos(0, 0, 0);
-    public static final int PACKED_HORIZONTAL_LENGTH = 1 + Mth.log2(Mth.smallestEncompassingPowerOfTwo(30000000));
-    public static final int PACKED_Y_LENGTH = 64 - 2 * PACKED_HORIZONTAL_LENGTH;
-    private static final long PACKED_X_MASK = (1L << PACKED_HORIZONTAL_LENGTH) - 1L;
-    private static final long PACKED_Y_MASK = (1L << PACKED_Y_LENGTH) - 1L;
-    private static final long PACKED_Z_MASK = (1L << PACKED_HORIZONTAL_LENGTH) - 1L;
+    // Paper start - Optimize Bit Operations by inlining
+    public static final int PACKED_HORIZONTAL_LENGTH = 26;
+    public static final int PACKED_Y_LENGTH = 12;
+    private static final long PACKED_X_MASK = 67108863;
+    private static final long PACKED_Y_MASK = 4095;
+    private static final long PACKED_Z_MASK = 67108863;
     private static final int Y_OFFSET = 0;
-    private static final int Z_OFFSET = PACKED_Y_LENGTH;
-    private static final int X_OFFSET = PACKED_Y_LENGTH + PACKED_HORIZONTAL_LENGTH;
-    public static final int MAX_HORIZONTAL_COORDINATE = (1 << PACKED_HORIZONTAL_LENGTH) / 2 - 1;
+    private static final int Z_OFFSET = 12;
+    private static final int X_OFFSET = 38;
+    public static final int MAX_HORIZONTAL_COORDINATE = 33554431;
+    // Paper end - Optimize Bit Operations by inlining
 
     public BlockPos(int x, int y, int z) {
         super(x, y, z);
@@ -69,28 +71,29 @@ public class BlockPos extends Vec3i {
         this(vector.getX(), vector.getY(), vector.getZ());
     }
 
+    public static long getAdjacent(int baseX, int baseY, int baseZ, Direction direction) { return asLong(baseX + direction.getStepX(), baseY + direction.getStepY(), baseZ + direction.getStepZ()); } // Paper
     public static long offset(long pos, Direction direction) {
         return offset(pos, direction.getStepX(), direction.getStepY(), direction.getStepZ());
     }
 
     public static long offset(long pos, int dx, int dy, int dz) {
-        return asLong(getX(pos) + dx, getY(pos) + dy, getZ(pos) + dz);
+        return asLong((int) (pos >> 38) + dx, (int) ((pos << 52) >> 52) + dy, (int) ((pos << 26) >> 38) + dz); // Paper - simplify/inline
     }
 
     public static int getX(long packedPos) {
-        return (int)(packedPos << 64 - X_OFFSET - PACKED_HORIZONTAL_LENGTH >> 64 - PACKED_HORIZONTAL_LENGTH);
+        return (int) (packedPos >> 38); // Paper - simplify/inline
     }
 
     public static int getY(long packedPos) {
-        return (int)(packedPos << 64 - PACKED_Y_LENGTH >> 64 - PACKED_Y_LENGTH);
+        return (int) ((packedPos << 52) >> 52); // Paper - simplify/inline
     }
 
     public static int getZ(long packedPos) {
-        return (int)(packedPos << 64 - Z_OFFSET - PACKED_HORIZONTAL_LENGTH >> 64 - PACKED_HORIZONTAL_LENGTH);
+        return (int) ((packedPos << 26) >> 38); // Paper - simplify/inline
     }
 
     public static BlockPos of(long packedPos) {
-        return new BlockPos(getX(packedPos), getY(packedPos), getZ(packedPos));
+        return new BlockPos((int) (packedPos >> 38), (int) ((packedPos << 52) >> 52), (int) ((packedPos << 26) >> 38)); // Paper - simplify/inline
     }
 
     public static BlockPos containing(double x, double y, double z) {
@@ -114,10 +117,7 @@ public class BlockPos extends Vec3i {
     }
 
     public static long asLong(int x, int y, int z) {
-        long l = 0L;
-        l |= (x & PACKED_X_MASK) << X_OFFSET;
-        l |= (y & PACKED_Y_MASK) << 0;
-        return l | (z & PACKED_Z_MASK) << Z_OFFSET;
+        return ((x & 67108863L) << 38) | ((y &  4095L)) | ((z & 67108863L) << 12); // Paper - inline constants and simplify
     }
 
     public static long getFlatIndex(long packedPos) {
diff --git a/net/minecraft/core/SectionPos.java b/net/minecraft/core/SectionPos.java
index 1780d8e14cea62971da75e4dcc80d1805434037b..ce8c394ea1a7bc5bf5c568c82e6158b19df517d8 100644
--- a/net/minecraft/core/SectionPos.java
+++ b/net/minecraft/core/SectionPos.java
@@ -38,7 +38,7 @@ public class SectionPos extends Vec3i {
     }
 
     public static SectionPos of(BlockPos pos) {
-        return new SectionPos(blockToSectionCoord(pos.getX()), blockToSectionCoord(pos.getY()), blockToSectionCoord(pos.getZ()));
+        return new SectionPos(pos.getX() >> 4, pos.getY() >> 4, pos.getZ() >> 4); // Paper
     }
 
     public static SectionPos of(ChunkPos chunkPos, int y) {
@@ -54,7 +54,7 @@ public class SectionPos extends Vec3i {
     }
 
     public static SectionPos of(long packed) {
-        return new SectionPos(x(packed), y(packed), z(packed));
+        return new SectionPos((int) (packed >> 42), (int) (packed << 44 >> 44), (int) (packed << 22 >> 42)); // Paper
     }
 
     public static SectionPos bottomOf(ChunkAccess chunk) {
@@ -65,8 +65,16 @@ public class SectionPos extends Vec3i {
         return offset(packed, direction.getStepX(), direction.getStepY(), direction.getStepZ());
     }
 
+    // Paper start
+    public static long getAdjacentFromBlockPos(int x, int y, int z, Direction direction) {
+        return (((long) ((x >> 4) + direction.getStepX()) & 4194303L) << 42) | (((long) ((y >> 4) + direction.getStepY()) & 1048575L)) | (((long) ((z >> 4) + direction.getStepZ()) & 4194303L) << 20);
+    }
+    public static long getAdjacentFromSectionPos(int x, int y, int z, Direction direction) {
+        return (((long) (x + direction.getStepX()) & 4194303L) << 42) | (((long) ((y) + direction.getStepY()) & 1048575L)) | (((long) (z + direction.getStepZ()) & 4194303L) << 20);
+    }
+    // Paper end
     public static long offset(long packed, int dx, int dy, int dz) {
-        return asLong(x(packed) + dx, y(packed) + dy, z(packed) + dz);
+        return (((long) ((int) (packed >> 42) + dx) & 4194303L) << 42) | (((long) ((int) (packed << 44 >> 44) + dy) & 1048575L)) | (((long) ((int) (packed << 22 >> 42) + dz) & 4194303L) << 20); // Simplify to reduce instruction count
     }
 
     public static int posToSectionCoord(double pos) {
@@ -86,10 +94,7 @@ public class SectionPos extends Vec3i {
     }
 
     public static short sectionRelativePos(BlockPos pos) {
-        int relativeBlockPosX = sectionRelative(pos.getX());
-        int relativeBlockPosY = sectionRelative(pos.getY());
-        int relativeBlockPosZ = sectionRelative(pos.getZ());
-        return (short)(relativeBlockPosX << 8 | relativeBlockPosZ << 4 | relativeBlockPosY << 0);
+        return (short) ((pos.getX() & 15) << 8 | (pos.getZ() & 15) << 4 | pos.getY() & 15); // Paper - simplify/inline
     }
 
     public static int sectionRelativeX(short x) {
@@ -152,16 +157,16 @@ public class SectionPos extends Vec3i {
         return this.getZ();
     }
 
-    public int minBlockX() {
-        return sectionToBlockCoord(this.x());
+    public final int minBlockX() { // Paper - final
+        return this.getX() << 4; // Paper - inline
     }
 
-    public int minBlockY() {
-        return sectionToBlockCoord(this.y());
+    public final int minBlockY() { // Paper - final
+        return this.getY() << 4; // Paper - inline
     }
 
-    public int minBlockZ() {
-        return sectionToBlockCoord(this.z());
+    public final int minBlockZ() { // Paper - final
+        return this.getZ() << 4; // Paper - inline
     }
 
     public int maxBlockX() {
@@ -177,7 +182,7 @@ public class SectionPos extends Vec3i {
     }
 
     public static long blockToSection(long levelPos) {
-        return asLong(blockToSectionCoord(BlockPos.getX(levelPos)), blockToSectionCoord(BlockPos.getY(levelPos)), blockToSectionCoord(BlockPos.getZ(levelPos)));
+        return (((long) (int) (levelPos >> 42) & 4194303L) << 42) | (((long) (int) ((levelPos << 52) >> 56) & 1048575L)) | (((long) (int) ((levelPos << 26) >> 42) & 4194303L) << 20); // Simplify to reduce instruction count
     }
 
     public static long getZeroNode(int x, int z) {
@@ -205,15 +210,17 @@ public class SectionPos extends Vec3i {
         return asLong(blockToSectionCoord(blockPos.getX()), blockToSectionCoord(blockPos.getY()), blockToSectionCoord(blockPos.getZ()));
     }
 
+    // Paper start
+    public static long blockPosAsSectionLong(int x, int y, int z) {
+        return (((long) (x >> 4) & 4194303L) << 42) | (((long) (y >> 4) & 1048575L)) | (((long) (z >> 4) & 4194303L) << 20);
+    }
+    // Paper end
     public static long asLong(int x, int y, int z) {
-        long l = 0L;
-        l |= (x & 4194303L) << 42;
-        l |= (y & 1048575L) << 0;
-        return l | (z & 4194303L) << 20;
+        return ((x & 4194303L) << 42) | ((y & 1048575L)) | ((z & 4194303L) << 20); // Paper - Simplify to reduce instruction count
     }
 
     public long asLong() {
-        return asLong(this.x(), this.y(), this.z());
+        return ((this.getX() & 4194303L) << 42) | ((this.getY() & 1048575L)) | ((this.getZ() & 4194303L) << 20); // Paper - Simplify to reduce instruction count
     }
 
     @Override
@@ -226,16 +233,13 @@ public class SectionPos extends Vec3i {
     }
 
     public static Stream<SectionPos> cube(SectionPos center, int radius) {
-        int sectionX = center.x();
-        int sectionY = center.y();
-        int sectionZ = center.z();
-        return betweenClosedStream(sectionX - radius, sectionY - radius, sectionZ - radius, sectionX + radius, sectionY + radius, sectionZ + radius);
+        return betweenClosedStream(center.getX() - radius, center.getY() - radius, center.getZ() - radius, center.getX() + radius, center.getY() + radius, center.getZ() + radius); // Paper - simplify/inline
     }
 
-    public static Stream<SectionPos> aroundChunk(ChunkPos chunkPos, int x, int y, int z) {
+    public static Stream<SectionPos> aroundChunk(ChunkPos chunkPos, int radius, int minY, int maxY) { // Paper - fix params
         int i = chunkPos.x;
         int i1 = chunkPos.z;
-        return betweenClosedStream(i - x, y, i1 - x, i + x, z, i1 + x);
+        return betweenClosedStream(i - radius, minY, i1 - radius, i + radius, maxY, i1 + radius); // Paper - simplify/inline
     }
 
     public static Stream<SectionPos> betweenClosedStream(final int x1, final int y1, final int z1, final int x2, final int y2, final int z2) {