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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-exception6//7//===----------------------------------------------------------------------===//8//9// Helper used by __mulvsi3, __mulvdi3 and __mulvti3.10//11//===----------------------------------------------------------------------===//12 13#include "int_lib.h"14 15// Returns: a * b16 17// Effects: aborts if a * b overflows18 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