-/** @file
- Compiler intrinsic to return the number of leading zeros, ported from LLVM code.
-
- Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
-
- This program and the accompanying materials
- are licensed and made available under the terms and conditions of the BSD License
- which accompanies this distribution. The full text of the license may be found at
- http://opensource.org/licenses/bsd-license.php
-
- THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
- WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
-
-**/
-/**
- University of Illinois/NCSA
- Open Source License
-
- Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign.
- All rights reserved.
-
- Developed by:
-
- LLVM Team
-
- University of Illinois at Urbana-Champaign
-
- http://llvm.org
-
- Permission is hereby granted, free of charge, to any person obtaining a copy of
- this software and associated documentation files (the "Software"), to deal with
- the Software without restriction, including without limitation the rights to
- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
- of the Software, and to permit persons to whom the Software is furnished to do
- so, subject to the following conditions:
-
- * Redistributions of source code must retain the above copyright notice,
- this list of conditions and the following disclaimers.
-
- * Redistributions in binary form must reproduce the above copyright notice,
- this list of conditions and the following disclaimers in the
- documentation and/or other materials provided with the distribution.
-
- * Neither the names of the LLVM Team, University of Illinois at
- Urbana-Champaign, nor the names of its contributors may be used to
- endorse or promote products derived from this Software without specific
- prior written permission.
-
- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
- SOFTWARE.
-**/
-
-
-#include "Llvm_int_lib.h"
-
-// Returns: the number of leading 0-bits
-
-// Precondition: a != 0
-
-INT32
-__clzsi2(INT32 a)
-{
- UINT32 x = (UINT32)a;
- INT32 t = ((x & 0xFFFF0000) == 0) << 4; // if (x is small) t = 16 else 0
- x >>= 16 - t; // x = [0 - 0xFFFF]
- UINT32 r = t; // r = [0, 16]
- // return r + clz(x)
- t = ((x & 0xFF00) == 0) << 3;
- x >>= 8 - t; // x = [0 - 0xFF]
- r += t; // r = [0, 8, 16, 24]
- // return r + clz(x)
- t = ((x & 0xF0) == 0) << 2;
- x >>= 4 - t; // x = [0 - 0xF]
- r += t; // r = [0, 4, 8, 12, 16, 20, 24, 28]
- // return r + clz(x)
- t = ((x & 0xC) == 0) << 1;
- x >>= 2 - t; // x = [0 - 3]
- r += t; // r = [0 - 30] and is even
- // return r + clz(x)
-// switch (x)
-// {
-// case 0:
-// return r + 2;
-// case 1:
-// return r + 1;
-// case 2:
-// case 3:
-// return r;
-// }
- return r + ((2 - x) & -((x & 2) == 0));
-}
+/** @file\r
+ Compiler intrinsic to return the number of leading zeros, ported from LLVM code.\r
+\r
+ Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>\r
+ \r
+ This program and the accompanying materials\r
+ are licensed and made available under the terms and conditions of the BSD License\r
+ which accompanies this distribution. The full text of the license may be found at\r
+ http://opensource.org/licenses/bsd-license.php\r
+\r
+ THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+\r
+**/\r
+/**\r
+ University of Illinois/NCSA\r
+ Open Source License\r
+ \r
+ Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign.\r
+ All rights reserved.\r
+ \r
+ Developed by:\r
+ \r
+ LLVM Team\r
+ \r
+ University of Illinois at Urbana-Champaign\r
+ \r
+ http://llvm.org\r
+ \r
+ Permission is hereby granted, free of charge, to any person obtaining a copy of\r
+ this software and associated documentation files (the "Software"), to deal with\r
+ the Software without restriction, including without limitation the rights to\r
+ use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies\r
+ of the Software, and to permit persons to whom the Software is furnished to do\r
+ so, subject to the following conditions:\r
+ \r
+ * Redistributions of source code must retain the above copyright notice,\r
+ this list of conditions and the following disclaimers.\r
+ \r
+ * Redistributions in binary form must reproduce the above copyright notice,\r
+ this list of conditions and the following disclaimers in the\r
+ documentation and/or other materials provided with the distribution.\r
+ \r
+ * Neither the names of the LLVM Team, University of Illinois at\r
+ Urbana-Champaign, nor the names of its contributors may be used to\r
+ endorse or promote products derived from this Software without specific\r
+ prior written permission.\r
+ \r
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\r
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS\r
+ FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE\r
+ CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER\r
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,\r
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE\r
+ SOFTWARE.\r
+**/\r
+\r
+\r
+#include "Llvm_int_lib.h"\r
+\r
+// Returns: the number of leading 0-bits\r
+\r
+// Precondition: a != 0\r
+\r
+INT32\r
+__clzsi2(INT32 a)\r
+{\r
+ UINT32 x = (UINT32)a;\r
+ INT32 t = ((x & 0xFFFF0000) == 0) << 4; // if (x is small) t = 16 else 0\r
+ x >>= 16 - t; // x = [0 - 0xFFFF]\r
+ UINT32 r = t; // r = [0, 16]\r
+ // return r + clz(x)\r
+ t = ((x & 0xFF00) == 0) << 3;\r
+ x >>= 8 - t; // x = [0 - 0xFF]\r
+ r += t; // r = [0, 8, 16, 24]\r
+ // return r + clz(x)\r
+ t = ((x & 0xF0) == 0) << 2;\r
+ x >>= 4 - t; // x = [0 - 0xF]\r
+ r += t; // r = [0, 4, 8, 12, 16, 20, 24, 28]\r
+ // return r + clz(x)\r
+ t = ((x & 0xC) == 0) << 1;\r
+ x >>= 2 - t; // x = [0 - 3]\r
+ r += t; // r = [0 - 30] and is even\r
+ // return r + clz(x)\r
+// switch (x)\r
+// {\r
+// case 0:\r
+// return r + 2;\r
+// case 1:\r
+// return r + 1;\r
+// case 2:\r
+// case 3:\r
+// return r;\r
+// }\r
+ return r + ((2 - x) & -((x & 2) == 0));\r
+}\r
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