1*0b57cec5SDimitry Andric //===-- mulvdi3.c - Implement __mulvdi3 -----------------------------------===// 2*0b57cec5SDimitry Andric // 3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*0b57cec5SDimitry Andric // 7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 8*0b57cec5SDimitry Andric // 9*0b57cec5SDimitry Andric // This file implements __mulvdi3 for the compiler_rt library. 10*0b57cec5SDimitry Andric // 11*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 12*0b57cec5SDimitry Andric 13*0b57cec5SDimitry Andric #include "int_lib.h" 14*0b57cec5SDimitry Andric 15*0b57cec5SDimitry Andric // Returns: a * b 16*0b57cec5SDimitry Andric 17*0b57cec5SDimitry Andric // Effects: aborts if a * b overflows 18*0b57cec5SDimitry Andric 19*0b57cec5SDimitry Andric COMPILER_RT_ABI di_int __mulvdi3(di_int a, di_int b) { 20*0b57cec5SDimitry Andric const int N = (int)(sizeof(di_int) * CHAR_BIT); 21*0b57cec5SDimitry Andric const di_int MIN = (di_int)1 << (N - 1); 22*0b57cec5SDimitry Andric const di_int MAX = ~MIN; 23*0b57cec5SDimitry Andric if (a == MIN) { 24*0b57cec5SDimitry Andric if (b == 0 || b == 1) 25*0b57cec5SDimitry Andric return a * b; 26*0b57cec5SDimitry Andric compilerrt_abort(); 27*0b57cec5SDimitry Andric } 28*0b57cec5SDimitry Andric if (b == MIN) { 29*0b57cec5SDimitry Andric if (a == 0 || a == 1) 30*0b57cec5SDimitry Andric return a * b; 31*0b57cec5SDimitry Andric compilerrt_abort(); 32*0b57cec5SDimitry Andric } 33*0b57cec5SDimitry Andric di_int sa = a >> (N - 1); 34*0b57cec5SDimitry Andric di_int abs_a = (a ^ sa) - sa; 35*0b57cec5SDimitry Andric di_int sb = b >> (N - 1); 36*0b57cec5SDimitry Andric di_int abs_b = (b ^ sb) - sb; 37*0b57cec5SDimitry Andric if (abs_a < 2 || abs_b < 2) 38*0b57cec5SDimitry Andric return a * b; 39*0b57cec5SDimitry Andric if (sa == sb) { 40*0b57cec5SDimitry Andric if (abs_a > MAX / abs_b) 41*0b57cec5SDimitry Andric compilerrt_abort(); 42*0b57cec5SDimitry Andric } else { 43*0b57cec5SDimitry Andric if (abs_a > MIN / -abs_b) 44*0b57cec5SDimitry Andric compilerrt_abort(); 45*0b57cec5SDimitry Andric } 46*0b57cec5SDimitry Andric return a * b; 47*0b57cec5SDimitry Andric } 48