diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java
index 87444049c..4bb5fe444 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java
@@ -316,6 +316,48 @@ public class TBitSet extends TObject implements TCloneable, TSerializable {
         return length;
     }
 
+    public int previousSetBit(int fromIndex) {
+        if (fromIndex == -1) {
+            return -1;
+        }
+        if (fromIndex >= length) {
+            fromIndex = length;
+        }
+        int index = fromIndex / 32;
+        int val = data[index];
+        val <<= 31 - (fromIndex % 32);
+        if (val != 0) {
+            return fromIndex - TInteger.numberOfLeadingZeros(val);
+        }
+        for (int i = index - 1; i >= 0; ++i) {
+            if (data[i] != 0) {
+                return (i + 1) * 32 - TInteger.numberOfLeadingZeros(data[i]) - 1;
+            }
+        }
+        return -1;
+    }
+
+    public int previousClearBit(int fromIndex) {
+        if (fromIndex == -1) {
+            return -1;
+        }
+        if (fromIndex >= length) {
+            return fromIndex;
+        }
+        int index = fromIndex / 32;
+        int val = ~data[index];
+        val <<= 31 - (fromIndex % 32);
+        if (val != 0) {
+            return fromIndex - TInteger.numberOfLeadingZeros(val);
+        }
+        for (int i = index - 1; i >= 0; ++i) {
+            if (data[i] != 0xFFFFFFFF) {
+                return (i + 1) * 32 - TInteger.numberOfLeadingZeros(~data[i]) - 1;
+            }
+        }
+        return -1;
+    }
+
     private void ensureCapacity(int capacity) {
         if (data.length >= capacity) {
             return;
diff --git a/teavm-classlib/src/test/java/org/teavm/classlib/java/util/BitSetTest.java b/teavm-classlib/src/test/java/org/teavm/classlib/java/util/BitSetTest.java
index ca9b2c120..53778433c 100644
--- a/teavm-classlib/src/test/java/org/teavm/classlib/java/util/BitSetTest.java
+++ b/teavm-classlib/src/test/java/org/teavm/classlib/java/util/BitSetTest.java
@@ -1146,4 +1146,56 @@ public class BitSetTest {
         bs.set(0, 500);
         assertEquals("cardinality() returned wrong value", 500, bs.cardinality());
     }
+
+    @Test
+    public void previousSetBitFound() {
+        BitSet bs = new BitSet();
+        bs.set(2, 10);
+        bs.set(16, 19);
+        bs.set(31, 64);
+        bs.set(96, 98);
+        assertEquals(97, bs.previousSetBit(100));
+        assertEquals(97, bs.previousSetBit(97));
+        assertEquals(96, bs.previousSetBit(96));
+        assertEquals(63, bs.previousSetBit(95));
+        assertEquals(63, bs.previousSetBit(63));
+        assertEquals(62, bs.previousSetBit(62));
+        assertEquals(32, bs.previousSetBit(32));
+        assertEquals(31, bs.previousSetBit(31));
+        assertEquals(18, bs.previousSetBit(30));
+        assertEquals(18, bs.previousSetBit(18));
+        assertEquals(17, bs.previousSetBit(17));
+        assertEquals(16, bs.previousSetBit(16));
+        assertEquals(9, bs.previousSetBit(15));
+        assertEquals(9, bs.previousSetBit(9));
+        assertEquals(2, bs.previousSetBit(2));
+        assertEquals(-1, bs.previousSetBit(1));
+        assertEquals(-1, bs.previousSetBit(0));
+    }
+
+    @Test
+    public void previousClearBitFound() {
+        BitSet bs = new BitSet();
+        bs.set(0, 10);
+        bs.set(16, 19);
+        bs.set(31, 64);
+        bs.set(96, 98);
+        assertEquals(100, bs.previousClearBit(100));
+        assertEquals(98, bs.previousClearBit(98));
+        assertEquals(95, bs.previousClearBit(97));
+        assertEquals(95, bs.previousClearBit(95));
+        assertEquals(64, bs.previousClearBit(64));
+        assertEquals(30, bs.previousClearBit(63));
+        assertEquals(30, bs.previousClearBit(32));
+        assertEquals(30, bs.previousClearBit(31));
+        assertEquals(30, bs.previousClearBit(30));
+        assertEquals(29, bs.previousClearBit(29));
+        assertEquals(20, bs.previousClearBit(20));
+        assertEquals(19, bs.previousClearBit(19));
+        assertEquals(15, bs.previousClearBit(17));
+        assertEquals(15, bs.previousClearBit(15));
+        assertEquals(-1, bs.previousClearBit(9));
+        assertEquals(-1, bs.previousClearBit(1));
+        assertEquals(-1, bs.previousClearBit(0));
+    }
 }