Fix IntegerUtil#getDivisorNumbers
Use unsigned mod operation for initialization of anc Also includes -5a0cefb45e
-acc8ed9634
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parent
02e3b5a91a
commit
3f237e869a
3 changed files with 68 additions and 17 deletions
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@ -3111,10 +3111,10 @@ index 0000000000000000000000000000000000000000..413e4b6da027876dbbe8eb78f2568a44
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+}
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diff --git a/src/main/java/io/papermc/paper/util/IntegerUtil.java b/src/main/java/io/papermc/paper/util/IntegerUtil.java
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new file mode 100644
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index 0000000000000000000000000000000000000000..a1bc1d1d0c86217ef18883d281195bc6b27e52ac
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index 0000000000000000000000000000000000000000..16785bd5c0524f6bad0691ca7ecd4514608d2eab
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--- /dev/null
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+++ b/src/main/java/io/papermc/paper/util/IntegerUtil.java
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@@ -0,0 +1,226 @@
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@@ -0,0 +1,242 @@
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+package io.papermc.paper.util;
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+
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+public final class IntegerUtil {
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@ -3214,7 +3214,7 @@ index 0000000000000000000000000000000000000000..a1bc1d1d0c86217ef18883d281195bc6
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+ // copied from hacker's delight (signed division magic value)
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+ // http://www.hackersdelight.org/hdcodetxt/magic.c.txt
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+ public static long getDivisorNumbers(final int d) {
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+ final int ad = IntegerUtil.branchlessAbs(d);
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+ final int ad = branchlessAbs(d);
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+
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+ if (ad < 2) {
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+ throw new IllegalArgumentException("|number| must be in [2, 2^31 -1], not: " + d);
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@ -3223,11 +3223,27 @@ index 0000000000000000000000000000000000000000..a1bc1d1d0c86217ef18883d281195bc6
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+ final int two31 = 0x80000000;
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+ final long mask = 0xFFFFFFFFL; // mask for enforcing unsigned behaviour
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+
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+ /*
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+ Signed usage:
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+ int number;
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+ long magic = getDivisorNumbers(div);
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+ long mul = magic >>> 32;
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+ int sign = number >> 31;
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+ int result = (int)(((long)number * mul) >>> magic) - sign;
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+ */
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+ /*
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+ Unsigned usage:
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+ int number;
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+ long magic = getDivisorNumbers(div);
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+ long mul = magic >>> 32;
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+ int result = (int)(((long)number * mul) >>> magic);
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+ */
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+
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+ int p = 31;
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+
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+ // all these variables are UNSIGNED!
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+ int t = two31 + (d >>> 31);
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+ int anc = t - 1 - t%ad;
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+ int anc = t - 1 - (int)((t & mask)%ad);
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+ int q1 = (int)((two31 & mask)/(anc & mask));
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+ int r1 = two31 - q1*anc;
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+ int q2 = (int)((two31 & mask)/(ad & mask));
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@ -3255,7 +3271,7 @@ index 0000000000000000000000000000000000000000..a1bc1d1d0c86217ef18883d281195bc6
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+ if (d < 0) {
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+ magicNum = -magicNum;
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+ }
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+ int shift = p - 32;
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+ int shift = p;
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+ return ((long)magicNum << 32) | shift;
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+ }
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+
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@ -6690,7 +6706,7 @@ index a0b5895abc88d297045e05f25bb09527991d43f0..6e0bd0eab0b06a4ac3042496bbb91292
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super(type, world);
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this.xpReward = 5;
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diff --git a/src/main/java/net/minecraft/world/item/ItemStack.java b/src/main/java/net/minecraft/world/item/ItemStack.java
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index 6375dfa336d232c7876e184690a1cb5c9bc2c495..2e948330c4951e3df7091fa870573f163d2af286 100644
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index a797c6dd17cf73feada7badccf47b4036f746405..6758e72177c0a407cf6c392b10263f095e4d06e8 100644
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--- a/src/main/java/net/minecraft/world/item/ItemStack.java
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+++ b/src/main/java/net/minecraft/world/item/ItemStack.java
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@@ -788,6 +788,25 @@ public final class ItemStack {
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