36 lines
1.3 KiB
C
36 lines
1.3 KiB
C
//===-- divsi3.c - Implement __divsi3 -------------------------------------===//
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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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//
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// This file implements __divsi3 for the compiler_rt library.
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//
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//===----------------------------------------------------------------------===//
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#include "int_lib.h"
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// Returns: a / b
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COMPILER_RT_ABI si_int __divsi3(si_int a, si_int b) {
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const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1;
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si_int s_a = a >> bits_in_word_m1; // s_a = a < 0 ? -1 : 0
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si_int s_b = b >> bits_in_word_m1; // s_b = b < 0 ? -1 : 0
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a = (a ^ s_a) - s_a; // negate if s_a == -1
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b = (b ^ s_b) - s_b; // negate if s_b == -1
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s_a ^= s_b; // sign of quotient
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//
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// On CPUs without unsigned hardware division support,
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// this calls __udivsi3 (notice the cast to su_int).
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// On CPUs with unsigned hardware division support,
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// this uses the unsigned division instruction.
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//
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return ((su_int)a / (su_int)b ^ s_a) - s_a; // negate if s_a == -1
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}
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#if defined(__ARM_EABI__)
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COMPILER_RT_ALIAS(__divsi3, __aeabi_idiv)
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#endif
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