1 //===-- muldi3.c - Implement __muldi3 -------------------------------------===// 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 // This file implements __muldi3 for the compiler_rt library. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "int_lib.h" 14 15 // Returns: a * b 16 17 static di_int __muldsi3(su_int a, su_int b) { 18 dwords r; 19 const int bits_in_word_2 = (int)(sizeof(si_int) * CHAR_BIT) / 2; 20 const su_int lower_mask = (su_int)~0 >> bits_in_word_2; 21 r.s.low = (a & lower_mask) * (b & lower_mask); 22 su_int t = r.s.low >> bits_in_word_2; 23 r.s.low &= lower_mask; 24 t += (a >> bits_in_word_2) * (b & lower_mask); 25 r.s.low += (t & lower_mask) << bits_in_word_2; 26 r.s.high = t >> bits_in_word_2; 27 t = r.s.low >> bits_in_word_2; 28 r.s.low &= lower_mask; 29 t += (b >> bits_in_word_2) * (a & lower_mask); 30 r.s.low += (t & lower_mask) << bits_in_word_2; 31 r.s.high += t >> bits_in_word_2; 32 r.s.high += (a >> bits_in_word_2) * (b >> bits_in_word_2); 33 return r.all; 34 } 35 36 // Returns: a * b 37 38 COMPILER_RT_ABI di_int __muldi3(di_int a, di_int b) { 39 dwords x; 40 x.all = a; 41 dwords y; 42 y.all = b; 43 dwords r; 44 r.all = __muldsi3(x.s.low, y.s.low); 45 r.s.high += x.s.high * y.s.low + x.s.low * y.s.high; 46 return r.all; 47 } 48 49 #if defined(__ARM_EABI__) 50 COMPILER_RT_ALIAS(__muldi3, __aeabi_lmul) 51 #endif 52