1214152Sed/*===-- mulvdi3.c - Implement __mulvdi3 -----------------------------------=== 2214152Sed * 3214152Sed * The LLVM Compiler Infrastructure 4214152Sed * 5222656Sed * This file is dual licensed under the MIT and the University of Illinois Open 6222656Sed * Source Licenses. See LICENSE.TXT for details. 7214152Sed * 8214152Sed * ===----------------------------------------------------------------------=== 9214152Sed * 10214152Sed * This file implements __mulvdi3 for the compiler_rt library. 11214152Sed * 12214152Sed * ===----------------------------------------------------------------------=== 13214152Sed */ 14214152Sed 15214152Sed#include "int_lib.h" 16214152Sed 17214152Sed/* Returns: a * b */ 18214152Sed 19214152Sed/* Effects: aborts if a * b overflows */ 20214152Sed 21214152Seddi_int 22214152Sed__mulvdi3(di_int a, di_int b) 23214152Sed{ 24214152Sed const int N = (int)(sizeof(di_int) * CHAR_BIT); 25214152Sed const di_int MIN = (di_int)1 << (N-1); 26214152Sed const di_int MAX = ~MIN; 27214152Sed if (a == MIN) 28214152Sed { 29214152Sed if (b == 0 || b == 1) 30214152Sed return a * b; 31214152Sed compilerrt_abort(); 32214152Sed } 33214152Sed if (b == MIN) 34214152Sed { 35214152Sed if (a == 0 || a == 1) 36214152Sed return a * b; 37214152Sed compilerrt_abort(); 38214152Sed } 39214152Sed di_int sa = a >> (N - 1); 40214152Sed di_int abs_a = (a ^ sa) - sa; 41214152Sed di_int sb = b >> (N - 1); 42214152Sed di_int abs_b = (b ^ sb) - sb; 43214152Sed if (abs_a < 2 || abs_b < 2) 44214152Sed return a * b; 45214152Sed if (sa == sb) 46214152Sed { 47214152Sed if (abs_a > MAX / abs_b) 48214152Sed compilerrt_abort(); 49214152Sed } 50214152Sed else 51214152Sed { 52214152Sed if (abs_a > MIN / -abs_b) 53214152Sed compilerrt_abort(); 54214152Sed } 55214152Sed return a * b; 56214152Sed} 57