mirror of https://github.com/acidanthera/audk.git
288 lines
9.4 KiB
C
288 lines
9.4 KiB
C
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/** @file
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Compiler intrinsic for 64-bit compare, ported from LLVM code.
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Copyright (c) 2008-2009, Apple Inc. All rights reserved.
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All rights reserved. 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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// Effects: if rem != 0, *rem = a % b
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// Returns: a / b
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// Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide
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UINT64
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__udivmoddi4 (UINT64 a, UINT64 b, UINT64* rem)
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{
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const unsigned n_uword_bits = sizeof(UINT32) * CHAR_BIT;
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const unsigned n_udword_bits = sizeof(UINT64) * CHAR_BIT;
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udwords n;
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n.all = a;
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udwords d;
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d.all = b;
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udwords q;
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udwords r;
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unsigned sr;
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if (b == 0) {
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// ASSERT (FALSE);
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return 0;
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}
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// special cases, X is unknown, K != 0
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if (n.high == 0)
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{
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if (d.high == 0)
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{
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// 0 X
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// ---
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// 0 X
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if (rem)
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*rem = n.low % d.low;
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return n.low / d.low;
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}
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// 0 X
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// ---
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// K X
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if (rem)
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*rem = n.low;
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return 0;
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}
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// n.high != 0
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if (d.low == 0)
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{
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if (d.high == 0)
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{
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// K X
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// ---
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// 0 0
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if (rem)
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*rem = n.high % d.low;
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return n.high / d.low;
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}
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// d.high != 0
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if (n.low == 0)
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{
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// K 0
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// ---
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// K 0
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if (rem)
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{
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r.high = n.high % d.high;
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r.low = 0;
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*rem = r.all;
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}
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return n.high / d.high;
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}
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// K K
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// ---
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// K 0
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if ((d.high & (d.high - 1)) == 0) // if d is a power of 2
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{
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if (rem)
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{
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r.low = n.low;
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r.high = n.high & (d.high - 1);
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*rem = r.all;
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}
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return n.high >> COUNT_TRAILING_ZEROS(d.high);
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}
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// K K
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// ---
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// K 0
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sr = COUNT_LEADING_ZEROS(d.high) - COUNT_LEADING_ZEROS(n.high);
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// 0 <= sr <= n_uword_bits - 2 or sr large
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if (sr > n_uword_bits - 2)
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{
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if (rem)
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*rem = n.all;
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return 0;
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}
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++sr;
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// 1 <= sr <= n_uword_bits - 1
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// q.all = n.all << (n_udword_bits - sr);
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q.low = 0;
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q.high = n.low << (n_uword_bits - sr);
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// r.all = n.all >> sr;
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r.high = n.high >> sr;
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r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr);
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}
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else // d.low != 0
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{
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if (d.high == 0)
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{
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// K X
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// ---
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// 0 K
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if ((d.low & (d.low - 1)) == 0) // if d is a power of 2
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{
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if (rem)
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*rem = n.low & (d.low - 1);
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if (d.low == 1)
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return n.all;
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unsigned sr = COUNT_TRAILING_ZEROS(d.low);
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q.high = n.high >> sr;
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q.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr);
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return q.all;
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}
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// K X
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// ---
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// 0 K
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sr = 1 + n_uword_bits + COUNT_LEADING_ZEROS(d.low) - COUNT_LEADING_ZEROS(n.high);
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// 2 <= sr <= n_udword_bits - 1
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// q.all = n.all << (n_udword_bits - sr);
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// r.all = n.all >> sr;
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// if (sr == n_uword_bits)
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// {
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// q.low = 0;
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// q.high = n.low;
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// r.high = 0;
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// r.low = n.high;
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// }
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// else if (sr < n_uword_bits) // 2 <= sr <= n_uword_bits - 1
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// {
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// q.low = 0;
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// q.high = n.low << (n_uword_bits - sr);
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// r.high = n.high >> sr;
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// r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr);
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// }
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// else // n_uword_bits + 1 <= sr <= n_udword_bits - 1
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// {
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// q.low = n.low << (n_udword_bits - sr);
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// q.high = (n.high << (n_udword_bits - sr)) |
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// (n.low >> (sr - n_uword_bits));
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// r.high = 0;
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// r.low = n.high >> (sr - n_uword_bits);
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// }
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q.low = (n.low << (n_udword_bits - sr)) &
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((INT32)(n_uword_bits - sr) >> (n_uword_bits-1));
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q.high = ((n.low << ( n_uword_bits - sr)) &
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((INT32)(sr - n_uword_bits - 1) >> (n_uword_bits-1))) |
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(((n.high << (n_udword_bits - sr)) |
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(n.low >> (sr - n_uword_bits))) &
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((INT32)(n_uword_bits - sr) >> (n_uword_bits-1)));
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r.high = (n.high >> sr) &
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((INT32)(sr - n_uword_bits) >> (n_uword_bits-1));
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r.low = ((n.high >> (sr - n_uword_bits)) &
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((INT32)(n_uword_bits - sr - 1) >> (n_uword_bits-1))) |
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(((n.high << (n_uword_bits - sr)) |
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(n.low >> sr)) &
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((INT32)(sr - n_uword_bits) >> (n_uword_bits-1)));
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}
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else
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{
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// K X
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// ---
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// K K
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sr = COUNT_LEADING_ZEROS(d.high) - COUNT_LEADING_ZEROS(n.high);
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// 0 <= sr <= n_uword_bits - 1 or sr large
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if (sr > n_uword_bits - 1)
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{
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if (rem)
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*rem = n.all;
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return 0;
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}
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++sr;
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// 1 <= sr <= n_uword_bits
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// q.all = n.all << (n_udword_bits - sr);
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q.low = 0;
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q.high = n.low << (n_uword_bits - sr);
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// r.all = n.all >> sr;
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// if (sr < n_uword_bits)
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// {
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// r.high = n.high >> sr;
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// r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr);
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// }
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// else
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// {
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// r.high = 0;
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// r.low = n.high;
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// }
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r.high = (n.high >> sr) &
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((INT32)(sr - n_uword_bits) >> (n_uword_bits-1));
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r.low = (n.high << (n_uword_bits - sr)) |
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((n.low >> sr) &
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((INT32)(sr - n_uword_bits) >> (n_uword_bits-1)));
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}
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}
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// Not a special case
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// q and r are initialized with:
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// q.all = n.all << (n_udword_bits - sr);
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// r.all = n.all >> sr;
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// 1 <= sr <= n_udword_bits - 1
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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.high = (r.high << 1) | (r.low >> (n_uword_bits - 1));
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r.low = (r.low << 1) | (q.high >> (n_uword_bits - 1));
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q.high = (q.high << 1) | (q.low >> (n_uword_bits - 1));
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q.low = (q.low << 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 INT64 s = (INT64)(d.all - r.all - 1) >> (n_udword_bits - 1);
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carry = s & 1;
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r.all -= d.all & s;
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}
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q.all = (q.all << 1) | carry;
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if (rem)
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*rem = r.all;
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return q.all;
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}
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