divsi3.c revision 276789
1276789Sdim/* ===-- divsi3.c - Implement __divsi3 -------------------------------------=== 2276789Sdim * 3276789Sdim * The LLVM Compiler Infrastructure 4276789Sdim * 5276789Sdim * This file is dual licensed under the MIT and the University of Illinois Open 6276789Sdim * Source Licenses. See LICENSE.TXT for details. 7276789Sdim * 8276789Sdim * ===----------------------------------------------------------------------=== 9276789Sdim * 10276789Sdim * This file implements __divsi3 for the compiler_rt library. 11276789Sdim * 12276789Sdim * ===----------------------------------------------------------------------=== 13276789Sdim */ 14276789Sdim 15276789Sdim#include "int_lib.h" 16276789Sdim 17276789Sdim/* Returns: a / b */ 18276789Sdim 19276789SdimARM_EABI_FNALIAS(idiv, divsi3) 20276789Sdim 21276789SdimCOMPILER_RT_ABI si_int 22276789Sdim__divsi3(si_int a, si_int b) 23276789Sdim{ 24276789Sdim const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1; 25276789Sdim si_int s_a = a >> bits_in_word_m1; /* s_a = a < 0 ? -1 : 0 */ 26276789Sdim si_int s_b = b >> bits_in_word_m1; /* s_b = b < 0 ? -1 : 0 */ 27276789Sdim a = (a ^ s_a) - s_a; /* negate if s_a == -1 */ 28276789Sdim b = (b ^ s_b) - s_b; /* negate if s_b == -1 */ 29276789Sdim s_a ^= s_b; /* sign of quotient */ 30276789Sdim /* 31276789Sdim * On CPUs without unsigned hardware division support, 32276789Sdim * this calls __udivsi3 (notice the cast to su_int). 33276789Sdim * On CPUs with unsigned hardware division support, 34276789Sdim * this uses the unsigned division instruction. 35276789Sdim */ 36276789Sdim return ((su_int)a/(su_int)b ^ s_a) - s_a; /* negate if s_a == -1 */ 37276789Sdim} 38