muldi3.c revision 222656
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#include "abi.h" 15 16#include "int_lib.h" 17 18/* Returns: a * b */ 19 20static 21di_int 22__muldsi3(su_int a, su_int b) 23{ 24 dwords r; 25 const int bits_in_word_2 = (int)(sizeof(si_int) * CHAR_BIT) / 2; 26 const su_int lower_mask = (su_int)~0 >> bits_in_word_2; 27 r.s.low = (a & lower_mask) * (b & lower_mask); 28 su_int t = r.s.low >> bits_in_word_2; 29 r.s.low &= lower_mask; 30 t += (a >> bits_in_word_2) * (b & lower_mask); 31 r.s.low += (t & lower_mask) << bits_in_word_2; 32 r.s.high = t >> bits_in_word_2; 33 t = r.s.low >> bits_in_word_2; 34 r.s.low &= lower_mask; 35 t += (b >> bits_in_word_2) * (a & lower_mask); 36 r.s.low += (t & lower_mask) << bits_in_word_2; 37 r.s.high += t >> bits_in_word_2; 38 r.s.high += (a >> bits_in_word_2) * (b >> bits_in_word_2); 39 return r.all; 40} 41 42/* Returns: a * b */ 43 44ARM_EABI_FNALIAS(lmul, muldi3); 45 46COMPILER_RT_ABI di_int 47__muldi3(di_int a, di_int b) 48{ 49 dwords x; 50 x.all = a; 51 dwords y; 52 y.all = b; 53 dwords r; 54 r.all = __muldsi3(x.s.low, y.s.low); 55 r.s.high += x.s.high * y.s.low + x.s.low * y.s.high; 56 return r.all; 57} 58