1*7c3d14c8STreehugger Robot /*===-- muloti4.c - Implement __muloti4 -----------------------------------=== 2*7c3d14c8STreehugger Robot * 3*7c3d14c8STreehugger Robot * The LLVM Compiler Infrastructure 4*7c3d14c8STreehugger Robot * 5*7c3d14c8STreehugger Robot * This file is dual licensed under the MIT and the University of Illinois Open 6*7c3d14c8STreehugger Robot * Source Licenses. See LICENSE.TXT for details. 7*7c3d14c8STreehugger Robot * 8*7c3d14c8STreehugger Robot * ===----------------------------------------------------------------------=== 9*7c3d14c8STreehugger Robot * 10*7c3d14c8STreehugger Robot * This file implements __muloti4 for the compiler_rt library. 11*7c3d14c8STreehugger Robot * 12*7c3d14c8STreehugger Robot * ===----------------------------------------------------------------------=== 13*7c3d14c8STreehugger Robot */ 14*7c3d14c8STreehugger Robot 15*7c3d14c8STreehugger Robot #include "int_lib.h" 16*7c3d14c8STreehugger Robot 17*7c3d14c8STreehugger Robot #ifdef CRT_HAS_128BIT 18*7c3d14c8STreehugger Robot 19*7c3d14c8STreehugger Robot /* Returns: a * b */ 20*7c3d14c8STreehugger Robot 21*7c3d14c8STreehugger Robot /* Effects: sets *overflow to 1 if a * b overflows */ 22*7c3d14c8STreehugger Robot 23*7c3d14c8STreehugger Robot COMPILER_RT_ABI ti_int __muloti4(ti_int a,ti_int b,int * overflow)24*7c3d14c8STreehugger Robot__muloti4(ti_int a, ti_int b, int* overflow) 25*7c3d14c8STreehugger Robot { 26*7c3d14c8STreehugger Robot const int N = (int)(sizeof(ti_int) * CHAR_BIT); 27*7c3d14c8STreehugger Robot const ti_int MIN = (ti_int)1 << (N-1); 28*7c3d14c8STreehugger Robot const ti_int MAX = ~MIN; 29*7c3d14c8STreehugger Robot *overflow = 0; 30*7c3d14c8STreehugger Robot ti_int result = a * b; 31*7c3d14c8STreehugger Robot if (a == MIN) 32*7c3d14c8STreehugger Robot { 33*7c3d14c8STreehugger Robot if (b != 0 && b != 1) 34*7c3d14c8STreehugger Robot *overflow = 1; 35*7c3d14c8STreehugger Robot return result; 36*7c3d14c8STreehugger Robot } 37*7c3d14c8STreehugger Robot if (b == MIN) 38*7c3d14c8STreehugger Robot { 39*7c3d14c8STreehugger Robot if (a != 0 && a != 1) 40*7c3d14c8STreehugger Robot *overflow = 1; 41*7c3d14c8STreehugger Robot return result; 42*7c3d14c8STreehugger Robot } 43*7c3d14c8STreehugger Robot ti_int sa = a >> (N - 1); 44*7c3d14c8STreehugger Robot ti_int abs_a = (a ^ sa) - sa; 45*7c3d14c8STreehugger Robot ti_int sb = b >> (N - 1); 46*7c3d14c8STreehugger Robot ti_int abs_b = (b ^ sb) - sb; 47*7c3d14c8STreehugger Robot if (abs_a < 2 || abs_b < 2) 48*7c3d14c8STreehugger Robot return result; 49*7c3d14c8STreehugger Robot if (sa == sb) 50*7c3d14c8STreehugger Robot { 51*7c3d14c8STreehugger Robot if (abs_a > MAX / abs_b) 52*7c3d14c8STreehugger Robot *overflow = 1; 53*7c3d14c8STreehugger Robot } 54*7c3d14c8STreehugger Robot else 55*7c3d14c8STreehugger Robot { 56*7c3d14c8STreehugger Robot if (abs_a > MIN / -abs_b) 57*7c3d14c8STreehugger Robot *overflow = 1; 58*7c3d14c8STreehugger Robot } 59*7c3d14c8STreehugger Robot return result; 60*7c3d14c8STreehugger Robot } 61*7c3d14c8STreehugger Robot 62*7c3d14c8STreehugger Robot #endif /* CRT_HAS_128BIT */ 63