40 lines
1.4 KiB
C
40 lines
1.4 KiB
C
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/* ===-- divsi3.c - Implement __divsi3 -------------------------------------===
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*
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* The LLVM Compiler Infrastructure
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*
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* This file is dual licensed under the MIT and the University of Illinois Open
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* Source Licenses. See LICENSE.TXT for details.
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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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*/
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#include "int_lib.h"
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su_int COMPILER_RT_ABI __udivsi3(su_int n, su_int d);
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/* Returns: a / b */
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ARM_EABI_FNALIAS(idiv, divsi3)
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COMPILER_RT_ABI si_int
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__divsi3(si_int a, si_int b)
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{
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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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