llvm-project/compiler-rt/lib/muldc3.c

75 lines
2.2 KiB
C

/* ===-- muldc3.c - Implement __muldc3 -------------------------------------===
*
* 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 __muldc3 for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
#include <math.h>
#include <complex.h>
/* Returns: the product of a + ib and c + id */
double _Complex
__muldc3(double __a, double __b, double __c, double __d)
{
double __ac = __a * __c;
double __bd = __b * __d;
double __ad = __a * __d;
double __bc = __b * __c;
double _Complex z;
__real__ z = __ac - __bd;
__imag__ z = __ad + __bc;
if (isnan(__real__ z) && isnan(__imag__ z))
{
int __recalc = 0;
if (isinf(__a) || isinf(__b))
{
__a = copysign(isinf(__a) ? 1 : 0, __a);
__b = copysign(isinf(__b) ? 1 : 0, __b);
if (isnan(__c))
__c = copysign(0, __c);
if (isnan(__d))
__d = copysign(0, __d);
__recalc = 1;
}
if (isinf(__c) || isinf(__d))
{
__c = copysign(isinf(__c) ? 1 : 0, __c);
__d = copysign(isinf(__d) ? 1 : 0, __d);
if (isnan(__a))
__a = copysign(0, __a);
if (isnan(__b))
__b = copysign(0, __b);
__recalc = 1;
}
if (!__recalc && (isinf(__ac) || isinf(__bd) ||
isinf(__ad) || isinf(__bc)))
{
if (isnan(__a))
__a = copysign(0, __a);
if (isnan(__b))
__b = copysign(0, __b);
if (isnan(__c))
__c = copysign(0, __c);
if (isnan(__d))
__d = copysign(0, __d);
__recalc = 1;
}
if (__recalc)
{
__real__ z = INFINITY * (__a * __c - __b * __d);
__imag__ z = INFINITY * (__a * __d + __b * __c);
}
}
return z;
}