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Diffstat (limited to 'ArmPkg/Library/CompilerIntrinsicsLib/Arm/udivsi3.c')
-rw-r--r-- | ArmPkg/Library/CompilerIntrinsicsLib/Arm/udivsi3.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/ArmPkg/Library/CompilerIntrinsicsLib/Arm/udivsi3.c b/ArmPkg/Library/CompilerIntrinsicsLib/Arm/udivsi3.c new file mode 100644 index 0000000000..59d5b23643 --- /dev/null +++ b/ArmPkg/Library/CompilerIntrinsicsLib/Arm/udivsi3.c @@ -0,0 +1,111 @@ +/** @file + Compiler intrinsic for 32-bit unsigned div, ported from LLVM code. + + Copyright (c) 2008-2009, Apple Inc. All rights reserved. + + All rights reserved. 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: n / d + +// Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide + +UINT32 +__udivsi3(UINT32 n, UINT32 d) +{ + const unsigned n_uword_bits = sizeof(UINT32) * CHAR_BIT; + UINT32 q; + UINT32 r; + unsigned sr; + + // special cases + if (d == 0) { +// ASSERT (FALSE); + return 0; // ?! + } + if (n == 0) + return 0; + + sr = COUNT_LEADING_ZEROS(d) - COUNT_LEADING_ZEROS(n); + // 0 <= sr <= n_uword_bits - 1 or sr large + if (sr > n_uword_bits - 1) // d > r + return 0; + if (sr == n_uword_bits - 1) // d == 1 + return n; + ++sr; + // 1 <= sr <= n_uword_bits - 1 + // Not a special case + q = n << (n_uword_bits - sr); + r = n >> sr; + UINT32 carry = 0; + for (; sr > 0; --sr) + { + // r:q = ((r:q) << 1) | carry + r = (r << 1) | (q >> (n_uword_bits - 1)); + q = (q << 1) | carry; + // carry = 0; + // if (r.all >= d.all) + // { + // r.all -= d.all; + // carry = 1; + // } + const INT32 s = (INT32)(d - r - 1) >> (n_uword_bits - 1); + carry = s & 1; + r -= d & s; + } + q = (q << 1) | carry; + return q; +} |