diff --git a/classlib/src/main/java/org/teavm/classlib/impl/text/DoubleAnalyzer.java b/classlib/src/main/java/org/teavm/classlib/impl/text/DoubleAnalyzer.java
index 3e52e0c71..90b25b9ed 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/text/DoubleAnalyzer.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/text/DoubleAnalyzer.java
@@ -22,10 +22,21 @@ public final class DoubleAnalyzer {
     public static final int DECIMAL_PRECISION = 18;
     public static final long DOUBLE_MAX_POS = 100000000000000000L;
     private static final long MAX_MANTISSA = Long.divideUnsigned(-1, 10);
+    private static final Result resultForLog10 = new Result();
 
     private DoubleAnalyzer() {
     }
 
+    public static int fastIntLog10(double d) {
+        var result = resultForLog10;
+        analyze(d, result);
+        var exponent = result.exponent;
+        if (exponent < 0 && result.mantissa > 100000000000000000L) {
+            ++exponent;
+        }
+        return exponent;
+    }
+
     public static void analyze(double d, Result result) {
         long bits = Double.doubleToLongBits(d);
         result.sign = (bits & (1L << 63)) != 0;
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TAbstractStringBuilder.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TAbstractStringBuilder.java
index b2bda3d00..c4e8ac1eb 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TAbstractStringBuilder.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TAbstractStringBuilder.java
@@ -23,11 +23,6 @@ import org.teavm.classlib.java.util.TArrays;
 
 class TAbstractStringBuilder implements TSerializable, TCharSequence {
     static class Constants {
-        static int[] intPowersOfTen = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000,
-                1000000000 };
-        static long[] longPowersOfTen = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000,
-                1000000000, 10000000000L, 100000000000L, 1000000000000L, 10000000000000L, 100000000000000L,
-                1000000000000000L, 10000000000000000L, 100000000000000000L, 1000000000000000000L };
         static final long[] longLogPowersOfTen = { 1, 10, 100, 10000, 100000000, 10000000000000000L, };
 
         static final DoubleAnalyzer.Result doubleAnalysisResult = new DoubleAnalyzer.Result();
diff --git a/classlib/src/main/java/org/teavm/classlib/java/math/TBigDecimal.java b/classlib/src/main/java/org/teavm/classlib/java/math/TBigDecimal.java
index 88eb7788f..72b7a11f3 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/math/TBigDecimal.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/math/TBigDecimal.java
@@ -16,6 +16,7 @@
 package org.teavm.classlib.java.math;
 
 import java.io.Serializable;
+import org.teavm.classlib.impl.text.DoubleAnalyzer;
 
 /**
  * This class represents immutable arbitrary precision decimal numbers. Each
@@ -1691,7 +1692,7 @@ public class TBigDecimal extends Number implements Comparable<TBigDecimal>, Seri
         // The ANSI standard X3.274-1996 algorithm
         int m = Math.abs(n);
         int mcPrecision = mc.getPrecision();
-        int elength = (int) Math.log10(m) + 1;   // decimal digits in 'n'
+        int elength = (int) DoubleAnalyzer.fastIntLog10(m) + 1;   // decimal digits in 'n'
         int oneBitMask; // mask of bits
         TBigDecimal accum; // the single accumulator
         TMathContext newPrecision = mc; // MathContext by default
@@ -1850,7 +1851,7 @@ public class TBigDecimal extends Number implements Comparable<TBigDecimal>, Seri
             } else if (bitLength >= 1) {
                 doubleUnsc = smallValue;
             }
-            decimalDigits += Math.log10(Math.abs(doubleUnsc));
+            decimalDigits += DoubleAnalyzer.fastIntLog10(Math.abs(doubleUnsc));
         } else {
             // (bitLength >= 1024)
             /* To calculate the precision for large numbers
@@ -2816,7 +2817,7 @@ public class TBigDecimal extends Number implements Comparable<TBigDecimal>, Seri
                     Long.signum(fraction) * (5 + compRem),
                     mc.getRoundingMode());
             // If after to add the increment the precision changed, we normalize the size
-            if (Math.log10(Math.abs(integer)) >= mc.getPrecision()) {
+            if (DoubleAnalyzer.fastIntLog10(Math.abs(integer)) >= mc.getPrecision()) {
                 integer /= 10;
                 newScale--;
             }
diff --git a/classlib/src/test/java/org/teavm/classlib/impl/text/DoubleAnalyzerTest.java b/classlib/src/test/java/org/teavm/classlib/impl/text/DoubleAnalyzerTest.java
new file mode 100644
index 000000000..1ba44302c
--- /dev/null
+++ b/classlib/src/test/java/org/teavm/classlib/impl/text/DoubleAnalyzerTest.java
@@ -0,0 +1,33 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.classlib.impl.text;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class DoubleAnalyzerTest {
+    @Test
+    public void decimalExponent() {
+        var numbers = new double[] { 1e-200, 1e-5, 1e-4, 1e-3, 1e-2, 1e-1, 1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e200 };
+        var result = new DoubleAnalyzer.Result();
+        for (var number : numbers) {
+            var e = number / 100;
+            assertEquals((int) Math.log10(number), DoubleAnalyzer.fastIntLog10(number));
+            assertEquals((int) Math.log10(number + e), DoubleAnalyzer.fastIntLog10(number + e));
+            assertEquals((int) Math.log10(number - e), DoubleAnalyzer.fastIntLog10(number - e));
+        }
+    }
+}
diff --git a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalArithmeticTest.java b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalArithmeticTest.java
index e45eb492d..d585ef3be 100644
--- a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalArithmeticTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalArithmeticTest.java
@@ -41,12 +41,9 @@ import java.math.MathContext;
 import java.math.RoundingMode;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMTestRunner;
-import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
-@SkipPlatform(TestPlatform.WASI)
 public class BigDecimalArithmeticTest {
     /**
      * Add two numbers of equal positive scales
diff --git a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalCompareTest.java b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalCompareTest.java
index 0420ae1ef..cc385c90b 100644
--- a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalCompareTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalCompareTest.java
@@ -46,12 +46,9 @@ import java.math.MathContext;
 import java.math.RoundingMode;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMTestRunner;
-import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
-@SkipPlatform(TestPlatform.WASI)
 public class BigDecimalCompareTest {
     /**
      * Abs() of a negative BigDecimal
diff --git a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalConstructorsTest.java b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalConstructorsTest.java
index 3f9c75bda..33195b950 100644
--- a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalConstructorsTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalConstructorsTest.java
@@ -44,12 +44,9 @@ import java.math.MathContext;
 import java.math.RoundingMode;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMTestRunner;
-import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
-@SkipPlatform(TestPlatform.WASI)
 public class BigDecimalConstructorsTest {
     /**
      * check ONE
diff --git a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalScaleOperationsTest.java b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalScaleOperationsTest.java
index 6ea05c0a1..6af1b1685 100644
--- a/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalScaleOperationsTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/math/BigDecimalScaleOperationsTest.java
@@ -44,12 +44,9 @@ import java.math.BigInteger;
 import java.math.RoundingMode;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMTestRunner;
-import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
-@SkipPlatform(TestPlatform.WASI)
 public class BigDecimalScaleOperationsTest {
     /**
      * Check the default scale
diff --git a/tests/src/test/java/org/teavm/classlib/java/math/BigIntegerToStringTest.java b/tests/src/test/java/org/teavm/classlib/java/math/BigIntegerToStringTest.java
index d81b55cf7..4107bfcda 100644
--- a/tests/src/test/java/org/teavm/classlib/java/math/BigIntegerToStringTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/math/BigIntegerToStringTest.java
@@ -40,12 +40,9 @@ import static org.junit.Assert.assertTrue;
 import java.math.BigInteger;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMTestRunner;
-import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
-@SkipPlatform(TestPlatform.WASI)
 public class BigIntegerToStringTest {
     /**
      * If 36 < radix < 2 it should be set to 10
diff --git a/tests/src/test/java/org/teavm/classlib/java/text/DecimalFormatTest.java b/tests/src/test/java/org/teavm/classlib/java/text/DecimalFormatTest.java
index c07dd3106..6a59645de 100644
--- a/tests/src/test/java/org/teavm/classlib/java/text/DecimalFormatTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/text/DecimalFormatTest.java
@@ -27,15 +27,12 @@ import java.util.Currency;
 import java.util.Locale;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMProperties;
 import org.teavm.junit.TeaVMProperty;
 import org.teavm.junit.TeaVMTestRunner;
-import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
 @TeaVMProperties(@TeaVMProperty(key = "java.util.Locale.available", value = "en, en_US, en_GB, ru, ru_RU"))
-@SkipPlatform(TestPlatform.WASI)
 public class DecimalFormatTest {
     private static DecimalFormatSymbols symbols = new DecimalFormatSymbols(Locale.ENGLISH);
 
diff --git a/tests/src/test/java/org/teavm/classlib/java/text/NumberFormatTest.java b/tests/src/test/java/org/teavm/classlib/java/text/NumberFormatTest.java
index b3e35c761..f65de08fa 100644
--- a/tests/src/test/java/org/teavm/classlib/java/text/NumberFormatTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/text/NumberFormatTest.java
@@ -23,16 +23,13 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.teavm.junit.EachTestCompiledSeparately;
 import org.teavm.junit.SkipJVM;
-import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMProperties;
 import org.teavm.junit.TeaVMProperty;
 import org.teavm.junit.TeaVMTestRunner;
-import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
 @TeaVMProperties(@TeaVMProperty(key = "java.util.Locale.available", value = "en, en_US, en_GB, ru, ru_RU"))
 @EachTestCompiledSeparately
-@SkipPlatform(TestPlatform.WASI)
 public class NumberFormatTest {
     @Test
     public void formatsNumber() {