1 files changed, 79 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/asm/ASMBitNextSet-generic.cpp b/src/VBox/Runtime/common/asm/ASMBitNextSet-generic.cpp
new file mode 100644
index 00000000..8233de1b
--- /dev/null
+++ b/src/VBox/Runtime/common/asm/ASMBitNextSet-generic.cpp
@@ -0,0 +1,79 @@
+/* $Id: ASMBitNextSet-generic.cpp $ */
+/** @file
+ * IPRT - ASMBitNextSet - generic C implementation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 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                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/asm.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+
+
+RTDECL(int) ASMBitNextSet(const volatile void RT_FAR *pvBitmap, uint32_t cBits, uint32_t iBitPrev) RT_NOTHROW_DEF
+{
+    const volatile uint32_t RT_FAR *pau32Bitmap = (const volatile uint32_t RT_FAR *)pvBitmap;
+    int                             iBit = ++iBitPrev & 31;
+    Assert(!(cBits & 31));
+    Assert(!((uintptr_t)pvBitmap & 3));
+    if (iBit)
+    {
+        /*
+         * Inspect the 32-bit word containing the unaligned bit.
+         */
+        uint32_t u32 = RT_LE2H_U32(pau32Bitmap[iBitPrev / 32]) >> iBit;
+        if (u32)
+            return iBitPrev + ASMBitFirstSetU32(u32) - 1;
+
+        /*
+         * Skip ahead and see if there is anything left to search.
+         */
+        iBitPrev |= 31;
+        iBitPrev++;
+        if (cBits <= (uint32_t)iBitPrev)
+            return -1;
+    }
+
+    /*
+     * 32-bit aligned search, let ASMBitFirstSet do the dirty work.
+     */
+    iBit = ASMBitFirstSet(&pau32Bitmap[iBitPrev / 32], cBits - iBitPrev);
+    if (iBit >= 0)
+        iBit += iBitPrev;
+    return iBit;
+}
+