compiler-rt/lib/builtins/muldc3.c

   1 //===-- muldc3.c - Implement __muldc3 -------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements __muldc3 for the compiler_rt library.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "int_lib.h"
  14 #include "int_math.h"
  15
  16 // Returns: the product of a + ib and c + id
  17
  18 COMPILER_RT_ABI Dcomplex __muldc3(double __a, double __b, double __c,
  19                                   double __d) {
  20   double __ac = __a * __c;
  21   double __bd = __b * __d;
  22   double __ad = __a * __d;
  23   double __bc = __b * __c;
  24   Dcomplex z;
  25   COMPLEX_REAL(z) = __ac - __bd;
  26   COMPLEX_IMAGINARY(z) = __ad + __bc;
  27   if (crt_isnan(COMPLEX_REAL(z)) && crt_isnan(COMPLEX_IMAGINARY(z))) {
  28     int __recalc = 0;
  29     if (crt_isinf(__a) || crt_isinf(__b)) {
  30       __a = crt_copysign(crt_isinf(__a) ? 1 : 0, __a);
  31       __b = crt_copysign(crt_isinf(__b) ? 1 : 0, __b);
  32       if (crt_isnan(__c))
  33         __c = crt_copysign(0, __c);
  34       if (crt_isnan(__d))
  35         __d = crt_copysign(0, __d);
  36       __recalc = 1;
  37     }
  38     if (crt_isinf(__c) || crt_isinf(__d)) {
  39       __c = crt_copysign(crt_isinf(__c) ? 1 : 0, __c);
  40       __d = crt_copysign(crt_isinf(__d) ? 1 : 0, __d);
  41       if (crt_isnan(__a))
  42         __a = crt_copysign(0, __a);
  43       if (crt_isnan(__b))
  44         __b = crt_copysign(0, __b);
  45       __recalc = 1;
  46     }
  47     if (!__recalc && (crt_isinf(__ac) || crt_isinf(__bd) || crt_isinf(__ad) ||
  48                       crt_isinf(__bc))) {
  49       if (crt_isnan(__a))
  50         __a = crt_copysign(0, __a);
  51       if (crt_isnan(__b))
  52         __b = crt_copysign(0, __b);
  53       if (crt_isnan(__c))
  54         __c = crt_copysign(0, __c);
  55       if (crt_isnan(__d))
  56         __d = crt_copysign(0, __d);
  57       __recalc = 1;
  58     }
  59     if (__recalc) {
  60       COMPLEX_REAL(z) = CRT_INFINITY * (__a * __c - __b * __d);
  61       COMPLEX_IMAGINARY(z) = CRT_INFINITY * (__a * __d + __b * __c);
  62     }
  63   }
  64   return z;
  65 }