1 files changed, 88 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/math/frexp.cpp b/src/VBox/Runtime/common/math/frexp.cpp
new file mode 100644
index 00000000..46c2f3dc
--- /dev/null
+++ b/src/VBox/Runtime/common/math/frexp.cpp
@@ -0,0 +1,88 @@
+/* $Id: frexp.cpp $ */
+/** @file
+ * IPRT - No-CRT - frexp().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/math.h>
+#include <iprt/assertcompile.h>
+#include <iprt/nocrt/limits.h>
+
+
+/* Similar to the fxtract instruction. */
+#undef frexp
+double RT_NOCRT(frexp)(double rdValue, int *piExp)
+{
+    RTFLOAT64U Value;
+    AssertCompile(sizeof(Value) == sizeof(rdValue));
+    Value.r = rdValue;
+
+    if (RTFLOAT64U_IS_NORMAL(&Value))
+    {
+        *piExp = (int)Value.s.uExponent - RTFLOAT64U_EXP_BIAS + 1;
+        Value.s.uExponent = RTFLOAT64U_EXP_BIAS - 1;
+    }
+    else if (RTFLOAT64U_IS_ZERO(&Value))
+    {
+        *piExp = 0;
+        return rdValue;
+    }
+    else if (RTFLOAT64U_IS_SUBNORMAL(&Value))
+    {
+        int      iExp      = -RTFLOAT64U_EXP_BIAS + 1;
+        uint64_t uFraction = Value.s64.uFraction;
+        while (!(uFraction & RT_BIT_64(RTFLOAT64U_FRACTION_BITS)))
+        {
+            iExp--;
+            uFraction <<= 1;
+        }
+        Value.s64.uFraction = uFraction;
+        Value.s64.uExponent = RTFLOAT64U_EXP_BIAS - 1;
+        *piExp = iExp + 1;
+    }
+    else
+    {
+        /* NaN, Inf */
+        *piExp = Value.s.fSign ? INT_MIN : INT_MAX;
+        return rdValue;
+    }
+    return Value.r;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(frexp);
+