1*0a6a1f1dSLionel Sambuc /*===-- muloti4.c - Implement __muloti4 -----------------------------------=== 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 __muloti4 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 #ifdef CRT_HAS_128BIT 18*0a6a1f1dSLionel Sambuc 19*0a6a1f1dSLionel Sambuc /* Returns: a * b */ 20*0a6a1f1dSLionel Sambuc 21*0a6a1f1dSLionel Sambuc /* Effects: sets *overflow to 1 if a * b overflows */ 22*0a6a1f1dSLionel Sambuc 23*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI ti_int __muloti4(ti_int a,ti_int b,int * overflow)24*0a6a1f1dSLionel Sambuc__muloti4(ti_int a, ti_int b, int* overflow) 25*0a6a1f1dSLionel Sambuc { 26*0a6a1f1dSLionel Sambuc const int N = (int)(sizeof(ti_int) * CHAR_BIT); 27*0a6a1f1dSLionel Sambuc const ti_int MIN = (ti_int)1 << (N-1); 28*0a6a1f1dSLionel Sambuc const ti_int MAX = ~MIN; 29*0a6a1f1dSLionel Sambuc *overflow = 0; 30*0a6a1f1dSLionel Sambuc ti_int result = a * b; 31*0a6a1f1dSLionel Sambuc if (a == MIN) 32*0a6a1f1dSLionel Sambuc { 33*0a6a1f1dSLionel Sambuc if (b != 0 && b != 1) 34*0a6a1f1dSLionel Sambuc *overflow = 1; 35*0a6a1f1dSLionel Sambuc return result; 36*0a6a1f1dSLionel Sambuc } 37*0a6a1f1dSLionel Sambuc if (b == MIN) 38*0a6a1f1dSLionel Sambuc { 39*0a6a1f1dSLionel Sambuc if (a != 0 && a != 1) 40*0a6a1f1dSLionel Sambuc *overflow = 1; 41*0a6a1f1dSLionel Sambuc return result; 42*0a6a1f1dSLionel Sambuc } 43*0a6a1f1dSLionel Sambuc ti_int sa = a >> (N - 1); 44*0a6a1f1dSLionel Sambuc ti_int abs_a = (a ^ sa) - sa; 45*0a6a1f1dSLionel Sambuc ti_int sb = b >> (N - 1); 46*0a6a1f1dSLionel Sambuc ti_int abs_b = (b ^ sb) - sb; 47*0a6a1f1dSLionel Sambuc if (abs_a < 2 || abs_b < 2) 48*0a6a1f1dSLionel Sambuc return result; 49*0a6a1f1dSLionel Sambuc if (sa == sb) 50*0a6a1f1dSLionel Sambuc { 51*0a6a1f1dSLionel Sambuc if (abs_a > MAX / abs_b) 52*0a6a1f1dSLionel Sambuc *overflow = 1; 53*0a6a1f1dSLionel Sambuc } 54*0a6a1f1dSLionel Sambuc else 55*0a6a1f1dSLionel Sambuc { 56*0a6a1f1dSLionel Sambuc if (abs_a > MIN / -abs_b) 57*0a6a1f1dSLionel Sambuc *overflow = 1; 58*0a6a1f1dSLionel Sambuc } 59*0a6a1f1dSLionel Sambuc return result; 60*0a6a1f1dSLionel Sambuc } 61*0a6a1f1dSLionel Sambuc 62*0a6a1f1dSLionel Sambuc #endif /* CRT_HAS_128BIT */ 63