mirror of https://github.com/acidanthera/audk.git
112 lines
3.7 KiB
C
112 lines
3.7 KiB
C
/** @file
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Compiler intrinsic for 32-bit unsigned div, ported from LLVM code.
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Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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/**
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University of Illinois/NCSA
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Open Source License
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Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign.
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All rights reserved.
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Developed by:
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LLVM Team
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University of Illinois at Urbana-Champaign
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http://llvm.org
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Permission is hereby granted, free of charge, to any person obtaining a copy of
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this software and associated documentation files (the "Software"), to deal with
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the Software without restriction, including without limitation the rights to
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use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
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of the Software, and to permit persons to whom the Software is furnished to do
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so, subject to the following conditions:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimers.
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* Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimers in the
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documentation and/or other materials provided with the distribution.
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* Neither the names of the LLVM Team, University of Illinois at
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Urbana-Champaign, nor the names of its contributors may be used to
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endorse or promote products derived from this Software without specific
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prior written permission.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
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SOFTWARE.
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**/
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#include "Llvm_int_lib.h"
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// Returns: n / d
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// Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide
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UINT32
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__udivsi3(UINT32 n, UINT32 d)
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{
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const unsigned n_uword_bits = sizeof(UINT32) * CHAR_BIT;
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UINT32 q;
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UINT32 r;
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unsigned sr;
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// special cases
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if (d == 0) {
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// ASSERT (FALSE);
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return 0; // ?!
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}
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if (n == 0)
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return 0;
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sr = COUNT_LEADING_ZEROS(d) - COUNT_LEADING_ZEROS(n);
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// 0 <= sr <= n_uword_bits - 1 or sr large
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if (sr > n_uword_bits - 1) // d > r
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return 0;
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if (sr == n_uword_bits - 1) // d == 1
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return n;
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++sr;
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// 1 <= sr <= n_uword_bits - 1
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// Not a special case
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q = n << (n_uword_bits - sr);
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r = n >> sr;
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UINT32 carry = 0;
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for (; sr > 0; --sr)
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{
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// r:q = ((r:q) << 1) | carry
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r = (r << 1) | (q >> (n_uword_bits - 1));
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q = (q << 1) | carry;
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// carry = 0;
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// if (r.all >= d.all)
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// {
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// r.all -= d.all;
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// carry = 1;
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// }
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const INT32 s = (INT32)(d - r - 1) >> (n_uword_bits - 1);
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carry = s & 1;
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r -= d & s;
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}
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q = (q << 1) | carry;
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return q;
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}
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