1 /* ===-- muldi3.c - Implement __muldi3 -------------------------------------=== 2 * 3 * The LLVM Compiler Infrastructure 4 * 5 * This file is dual licensed under the MIT and the University of Illinois Open 6 * Source Licenses. See LICENSE.TXT for details. 7 * 8 * ===----------------------------------------------------------------------=== 9 * 10 * This file implements __muldi3 for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #include "int_lib.h" 16 17 /* Returns: a * b */ 18 19 static 20 di_int 21 __muldsi3(su_int a, su_int b) 22 { 23 dwords r; 24 const int bits_in_word_2 = (int)(sizeof(si_int) * CHAR_BIT) / 2; 25 const su_int lower_mask = (su_int)~0 >> bits_in_word_2; 26 r.s.low = (a & lower_mask) * (b & lower_mask); 27 su_int t = r.s.low >> bits_in_word_2; 28 r.s.low &= lower_mask; 29 t += (a >> bits_in_word_2) * (b & lower_mask); 30 r.s.low += (t & lower_mask) << bits_in_word_2; 31 r.s.high = t >> bits_in_word_2; 32 t = r.s.low >> bits_in_word_2; 33 r.s.low &= lower_mask; 34 t += (b >> bits_in_word_2) * (a & lower_mask); 35 r.s.low += (t & lower_mask) << bits_in_word_2; 36 r.s.high += t >> bits_in_word_2; 37 r.s.high += (a >> bits_in_word_2) * (b >> bits_in_word_2); 38 return r.all; 39 } 40 41 /* Returns: a * b */ 42 43 ARM_EABI_FNALIAS(lmul, muldi3) 44 45 COMPILER_RT_ABI di_int 46 __muldi3(di_int a, di_int b) 47 { 48 dwords x; 49 x.all = a; 50 dwords y; 51 y.all = b; 52 dwords r; 53 r.all = __muldsi3(x.s.low, y.s.low); 54 r.s.high += x.s.high * y.s.low + x.s.low * y.s.high; 55 return r.all; 56 } 57
