1*0a6a1f1dSLionel Sambuc /*===-- mulodi4.c - Implement __mulodi4 -----------------------------------=== 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 __mulodi4 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 19*0a6a1f1dSLionel Sambuc /* Effects: sets *overflow to 1 if a * b overflows */ 20*0a6a1f1dSLionel Sambuc 21*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI di_int __mulodi4(di_int a,di_int b,int * overflow)22*0a6a1f1dSLionel Sambuc__mulodi4(di_int a, di_int b, int* overflow) 23*0a6a1f1dSLionel Sambuc { 24*0a6a1f1dSLionel Sambuc const int N = (int)(sizeof(di_int) * CHAR_BIT); 25*0a6a1f1dSLionel Sambuc const di_int MIN = (di_int)1 << (N-1); 26*0a6a1f1dSLionel Sambuc const di_int MAX = ~MIN; 27*0a6a1f1dSLionel Sambuc *overflow = 0; 28*0a6a1f1dSLionel Sambuc di_int result = a * b; 29*0a6a1f1dSLionel Sambuc if (a == MIN) 30*0a6a1f1dSLionel Sambuc { 31*0a6a1f1dSLionel Sambuc if (b != 0 && b != 1) 32*0a6a1f1dSLionel Sambuc *overflow = 1; 33*0a6a1f1dSLionel Sambuc return result; 34*0a6a1f1dSLionel Sambuc } 35*0a6a1f1dSLionel Sambuc if (b == MIN) 36*0a6a1f1dSLionel Sambuc { 37*0a6a1f1dSLionel Sambuc if (a != 0 && a != 1) 38*0a6a1f1dSLionel Sambuc *overflow = 1; 39*0a6a1f1dSLionel Sambuc return result; 40*0a6a1f1dSLionel Sambuc } 41*0a6a1f1dSLionel Sambuc di_int sa = a >> (N - 1); 42*0a6a1f1dSLionel Sambuc di_int abs_a = (a ^ sa) - sa; 43*0a6a1f1dSLionel Sambuc di_int sb = b >> (N - 1); 44*0a6a1f1dSLionel Sambuc di_int abs_b = (b ^ sb) - sb; 45*0a6a1f1dSLionel Sambuc if (abs_a < 2 || abs_b < 2) 46*0a6a1f1dSLionel Sambuc return result; 47*0a6a1f1dSLionel Sambuc if (sa == sb) 48*0a6a1f1dSLionel Sambuc { 49*0a6a1f1dSLionel Sambuc if (abs_a > MAX / abs_b) 50*0a6a1f1dSLionel Sambuc *overflow = 1; 51*0a6a1f1dSLionel Sambuc } 52*0a6a1f1dSLionel Sambuc else 53*0a6a1f1dSLionel Sambuc { 54*0a6a1f1dSLionel Sambuc if (abs_a > MIN / -abs_b) 55*0a6a1f1dSLionel Sambuc *overflow = 1; 56*0a6a1f1dSLionel Sambuc } 57*0a6a1f1dSLionel Sambuc return result; 58*0a6a1f1dSLionel Sambuc } 59