57b08b0944
to reflect the new license. These used slightly different spellings that defeated my regular expressions. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351648
58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
/* ===-- multi3.c - Implement __multi3 -------------------------------------===
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*
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* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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* See https://llvm.org/LICENSE.txt for license information.
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* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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*
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* ===----------------------------------------------------------------------===
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* This file implements __multi3 for the compiler_rt library.
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*
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* ===----------------------------------------------------------------------===
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*/
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#include "int_lib.h"
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#ifdef CRT_HAS_128BIT
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/* Returns: a * b */
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static
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ti_int
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__mulddi3(du_int a, du_int b)
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{
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twords r;
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const int bits_in_dword_2 = (int)(sizeof(di_int) * CHAR_BIT) / 2;
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const du_int lower_mask = (du_int)~0 >> bits_in_dword_2;
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r.s.low = (a & lower_mask) * (b & lower_mask);
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du_int t = r.s.low >> bits_in_dword_2;
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r.s.low &= lower_mask;
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t += (a >> bits_in_dword_2) * (b & lower_mask);
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r.s.low += (t & lower_mask) << bits_in_dword_2;
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r.s.high = t >> bits_in_dword_2;
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t = r.s.low >> bits_in_dword_2;
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r.s.low &= lower_mask;
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t += (b >> bits_in_dword_2) * (a & lower_mask);
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r.s.low += (t & lower_mask) << bits_in_dword_2;
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r.s.high += t >> bits_in_dword_2;
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r.s.high += (a >> bits_in_dword_2) * (b >> bits_in_dword_2);
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return r.all;
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}
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/* Returns: a * b */
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COMPILER_RT_ABI ti_int
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__multi3(ti_int a, ti_int b)
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{
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twords x;
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x.all = a;
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twords y;
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y.all = b;
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twords r;
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r.all = __mulddi3(x.s.low, y.s.low);
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r.s.high += x.s.high * y.s.low + x.s.low * y.s.high;
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return r.all;
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}
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#endif /* CRT_HAS_128BIT */
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