| 1 | //===-- divmodsi4.c - Implement __divmodsi4 |
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| 2 | //--------------------------------===// |
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| 3 | // |
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| 4 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 5 | // See https://llvm.org/LICENSE.txt for license information. |
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| 6 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 7 | // |
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| 8 | //===----------------------------------------------------------------------===// |
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| 9 | // |
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| 10 | // This file implements __divmodsi4 for the compiler_rt library. |
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| 11 | // |
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| 12 | //===----------------------------------------------------------------------===// |
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| 13 | |
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| 14 | #include "int_lib.h" |
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| 15 | |
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| 16 | // Returns: a / b, *rem = a % b |
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| 17 | |
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| 18 | COMPILER_RT_ABI si_int __divmodsi4(si_int a, si_int b, si_int *rem) { |
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| 19 | const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1; |
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| 20 | si_int s_a = a >> bits_in_word_m1; // s_a = a < 0 ? -1 : 0 |
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| 21 | si_int s_b = b >> bits_in_word_m1; // s_b = b < 0 ? -1 : 0 |
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| 22 | a = (su_int)(a ^ s_a) - s_a; // negate if s_a == -1 |
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| 23 | b = (su_int)(b ^ s_b) - s_b; // negate if s_b == -1 |
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| 24 | s_b ^= s_a; // sign of quotient |
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| 25 | su_int r; |
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| 26 | si_int q = (__udivmodsi4(a, b, rem: &r) ^ s_b) - s_b; // negate if s_b == -1 |
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| 27 | *rem = (r ^ s_a) - s_a; // negate if s_a == -1 |
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| 28 | return q; |
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| 29 | } |
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| 30 | |
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