59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
|
/* ===-- multi3.c - Implement __multi3 -------------------------------------===
|
||
|
|
*
|
||
|
|
* The LLVM Compiler Infrastructure
|
||
|
|
*
|
||
|
|
* This file is dual licensed under the MIT and the University of Illinois Open
|
||
|
|
* Source Licenses. See LICENSE.TXT for details.
|
||
|
|
*
|
||
|
|
* ===----------------------------------------------------------------------===
|
||
|
|
|
||
|
|
* This file implements __multi3 for the compiler_rt library.
|
||
|
|
*
|
||
|
|
* ===----------------------------------------------------------------------===
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "int_lib.h"
|
||
|
|
|
||
|
|
#if __x86_64
|
||
|
|
|
||
|
|
/* Returns: a * b */
|
||
|
|
|
||
|
|
static
|
||
|
|
ti_int
|
||
|
|
__mulddi3(du_int a, du_int b)
|
||
|
|
{
|
||
|
|
twords r;
|
||
|
|
const int bits_in_dword_2 = (int)(sizeof(di_int) * CHAR_BIT) / 2;
|
||
|
|
const du_int lower_mask = (du_int)~0 >> bits_in_dword_2;
|
||
|
|
r.s.low = (a & lower_mask) * (b & lower_mask);
|
||
|
|
du_int t = r.s.low >> bits_in_dword_2;
|
||
|
|
r.s.low &= lower_mask;
|
||
|
|
t += (a >> bits_in_dword_2) * (b & lower_mask);
|
||
|
|
r.s.low += (t & lower_mask) << bits_in_dword_2;
|
||
|
|
r.s.high = t >> bits_in_dword_2;
|
||
|
|
t = r.s.low >> bits_in_dword_2;
|
||
|
|
r.s.low &= lower_mask;
|
||
|
|
t += (b >> bits_in_dword_2) * (a & lower_mask);
|
||
|
|
r.s.low += (t & lower_mask) << bits_in_dword_2;
|
||
|
|
r.s.high += t >> bits_in_dword_2;
|
||
|
|
r.s.high += (a >> bits_in_dword_2) * (b >> bits_in_dword_2);
|
||
|
|
return r.all;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Returns: a * b */
|
||
|
|
|
||
|
|
ti_int
|
||
|
|
__multi3(ti_int a, ti_int b)
|
||
|
|
{
|
||
|
|
twords x;
|
||
|
|
x.all = a;
|
||
|
|
twords y;
|
||
|
|
y.all = b;
|
||
|
|
twords r;
|
||
|
|
r.all = __mulddi3(x.s.low, y.s.low);
|
||
|
|
r.s.high += x.s.high * y.s.low + x.s.low * y.s.high;
|
||
|
|
return r.all;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* __x86_64 */
|