1 /* ===-- mulvsi3.c - Implement __mulvsi3 -----------------------------------===
3 * The LLVM Compiler Infrastructure
5 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
8 * ===----------------------------------------------------------------------===
10 * This file implements __mulvsi3 for the compiler_rt library.
12 * ===----------------------------------------------------------------------===
20 /* Effects: aborts if a * b overflows */
23 __mulvsi3(si_int a, si_int b)
25 const int N = (int)(sizeof(si_int) * CHAR_BIT);
26 const si_int MIN = (si_int)1 << (N-1);
27 const si_int MAX = ~MIN;
40 si_int sa = a >> (N - 1);
41 si_int abs_a = (a ^ sa) - sa;
42 si_int sb = b >> (N - 1);
43 si_int abs_b = (b ^ sb) - sb;
44 if (abs_a < 2 || abs_b < 2)
48 if (abs_a > MAX / abs_b)
53 if (abs_a > MIN / -abs_b)