1*0a6a1f1dSLionel Sambuc /* ===-- divsi3.c - Implement __divsi3 -------------------------------------=== 2*0a6a1f1dSLionel Sambuc * 3*0a6a1f1dSLionel Sambuc * The LLVM Compiler Infrastructure 4*0a6a1f1dSLionel Sambuc * 5*0a6a1f1dSLionel Sambuc * This file is dual licensed under the MIT and the University of Illinois Open 6*0a6a1f1dSLionel Sambuc * Source Licenses. See LICENSE.TXT for details. 7*0a6a1f1dSLionel Sambuc * 8*0a6a1f1dSLionel Sambuc * ===----------------------------------------------------------------------=== 9*0a6a1f1dSLionel Sambuc * 10*0a6a1f1dSLionel Sambuc * This file implements __divsi3 for the compiler_rt library. 11*0a6a1f1dSLionel Sambuc * 12*0a6a1f1dSLionel Sambuc * ===----------------------------------------------------------------------=== 13*0a6a1f1dSLionel Sambuc */ 14*0a6a1f1dSLionel Sambuc 15*0a6a1f1dSLionel Sambuc #include "int_lib.h" 16*0a6a1f1dSLionel Sambuc 17*0a6a1f1dSLionel Sambuc /* Returns: a / b */ 18*0a6a1f1dSLionel Sambuc ARM_EABI_FNALIAS(idiv,divsi3)19*0a6a1f1dSLionel SambucARM_EABI_FNALIAS(idiv, divsi3) 20*0a6a1f1dSLionel Sambuc 21*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI si_int 22*0a6a1f1dSLionel Sambuc __divsi3(si_int a, si_int b) 23*0a6a1f1dSLionel Sambuc { 24*0a6a1f1dSLionel Sambuc const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1; 25*0a6a1f1dSLionel Sambuc si_int s_a = a >> bits_in_word_m1; /* s_a = a < 0 ? -1 : 0 */ 26*0a6a1f1dSLionel Sambuc si_int s_b = b >> bits_in_word_m1; /* s_b = b < 0 ? -1 : 0 */ 27*0a6a1f1dSLionel Sambuc a = (a ^ s_a) - s_a; /* negate if s_a == -1 */ 28*0a6a1f1dSLionel Sambuc b = (b ^ s_b) - s_b; /* negate if s_b == -1 */ 29*0a6a1f1dSLionel Sambuc s_a ^= s_b; /* sign of quotient */ 30*0a6a1f1dSLionel Sambuc /* 31*0a6a1f1dSLionel Sambuc * On CPUs without unsigned hardware division support, 32*0a6a1f1dSLionel Sambuc * this calls __udivsi3 (notice the cast to su_int). 33*0a6a1f1dSLionel Sambuc * On CPUs with unsigned hardware division support, 34*0a6a1f1dSLionel Sambuc * this uses the unsigned division instruction. 35*0a6a1f1dSLionel Sambuc */ 36*0a6a1f1dSLionel Sambuc return ((su_int)a/(su_int)b ^ s_a) - s_a; /* negate if s_a == -1 */ 37*0a6a1f1dSLionel Sambuc } 38