LibJS: Add Math.clz32()

2 files changed, 13 insertions, 0 deletions

diff --git a/Libraries/LibJS/Runtime/MathObject.cpp b/Libraries/LibJS/Runtime/MathObject.cpp
index 2b173bcc70..73ee7696c0 100644
--- a/Libraries/LibJS/Runtime/MathObject.cpp
+++ b/Libraries/LibJS/Runtime/MathObject.cpp
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020, Linus Groh <mail@linusgroh.de>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,6 +54,7 @@ MathObject::MathObject()
     put_native_function("exp", exp, 1, attr);
     put_native_function("expm1", expm1, 1, attr);
     put_native_function("sign", sign, 1, attr);
+    put_native_function("clz32", clz32, 1, attr);
 
     put("E", Value(M_E), 0);
     put("LN2", Value(M_LN2), 0);
@@ -245,4 +247,14 @@ Value MathObject::sign(Interpreter& interpreter)
     return js_nan();
 }
 
+Value MathObject::clz32(Interpreter& interpreter)
+{
+    auto number = interpreter.argument(0).to_number(interpreter);
+    if (interpreter.exception())
+        return {};
+    if (!number.is_finite_number() || (unsigned)number.as_double() == 0)
+        return Value(32);
+    return Value(__builtin_clz((unsigned)number.as_double()));
+}
+
 }
diff --git a/Libraries/LibJS/Runtime/MathObject.h b/Libraries/LibJS/Runtime/MathObject.h
index e9902e6d53..1cd550ca7d 100644
--- a/Libraries/LibJS/Runtime/MathObject.h
+++ b/Libraries/LibJS/Runtime/MathObject.h
@@ -54,6 +54,7 @@ private:
     static Value exp(Interpreter&);
     static Value expm1(Interpreter&);
     static Value sign(Interpreter&);
+    static Value clz32(Interpreter&);
 };
 
 }