1//===-- int_mulv_impl.inc - Implement __mulv[sdt]i3 ---------------*- C -*-===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// Helper used by __mulvsi3, __mulvdi3 and __mulvti3. 10// 11//===----------------------------------------------------------------------===// 12 13#include "int_lib.h" 14 15// Returns: a * b 16 17// Effects: aborts if a * b overflows 18 19static __inline fixint_t __mulvXi3(fixint_t a, fixint_t b) { 20 const int N = (int)(sizeof(fixint_t) * CHAR_BIT); 21 const fixint_t MIN = (fixint_t)((fixuint_t)1 << (N - 1)); 22 const fixint_t MAX = ~MIN; 23 if (a == MIN) { 24 if (b == 0 || b == 1) 25 return a * b; 26 compilerrt_abort(); 27 } 28 if (b == MIN) { 29 if (a == 0 || a == 1) 30 return a * b; 31 compilerrt_abort(); 32 } 33 fixint_t sa = a >> (N - 1); 34 fixint_t abs_a = (a ^ sa) - sa; 35 fixint_t sb = b >> (N - 1); 36 fixint_t abs_b = (b ^ sb) - sb; 37 if (abs_a < 2 || abs_b < 2) 38 return a * b; 39 if (sa == sb) { 40 if (abs_a > MAX / abs_b) 41 compilerrt_abort(); 42 } else { 43 if (abs_a > MIN / -abs_b) 44 compilerrt_abort(); 45 } 46 return a * b; 47} 48