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
19static
20di_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
43ARM_EABI_FNALIAS(lmul, muldi3)
44
45COMPILER_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