divtc3.c revision 353358 
1// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
2// See https://llvm.org/LICENSE.txt for license information.
3// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
4
5#include "../int_math.h"
6#include "DD.h"
7// Use DOUBLE_PRECISION because the soft-fp method we use is logb (on the upper
8// half of the long doubles), even though this file defines complex division for
9// 128-bit floats.
10#define DOUBLE_PRECISION
11#include "../fp_lib.h"
12
13#if !defined(CRT_INFINITY) && defined(HUGE_VAL)
14#define CRT_INFINITY HUGE_VAL
15#endif // CRT_INFINITY
16
17#define makeFinite(x)                                                          \
18  {                                                                            \
19    (x).s.hi = crt_copysign(crt_isinf((x).s.hi) ? 1.0 : 0.0, (x).s.hi);        \
20    (x).s.lo = 0.0;                                                            \
21  }
22
23long double _Complex __divtc3(long double a, long double b, long double c,
24                              long double d) {
25  DD cDD = {.ld = c};
26  DD dDD = {.ld = d};
27
28  int ilogbw = 0;
29  const double logbw =
30      __compiler_rt_logb(crt_fmax(crt_fabs(cDD.s.hi), crt_fabs(dDD.s.hi)));
31
32  if (crt_isfinite(logbw)) {
33    ilogbw = (int)logbw;
34
35    cDD.s.hi = crt_scalbn(cDD.s.hi, -ilogbw);
36    cDD.s.lo = crt_scalbn(cDD.s.lo, -ilogbw);
37    dDD.s.hi = crt_scalbn(dDD.s.hi, -ilogbw);
38    dDD.s.lo = crt_scalbn(dDD.s.lo, -ilogbw);
39  }
40
41  const long double denom =
42      __gcc_qadd(__gcc_qmul(cDD.ld, cDD.ld), __gcc_qmul(dDD.ld, dDD.ld));
43  const long double realNumerator =
44      __gcc_qadd(__gcc_qmul(a, cDD.ld), __gcc_qmul(b, dDD.ld));
45  const long double imagNumerator =
46      __gcc_qsub(__gcc_qmul(b, cDD.ld), __gcc_qmul(a, dDD.ld));
47
48  DD real = {.ld = __gcc_qdiv(realNumerator, denom)};
49  DD imag = {.ld = __gcc_qdiv(imagNumerator, denom)};
50
51  real.s.hi = crt_scalbn(real.s.hi, -ilogbw);
52  real.s.lo = crt_scalbn(real.s.lo, -ilogbw);
53  imag.s.hi = crt_scalbn(imag.s.hi, -ilogbw);
54  imag.s.lo = crt_scalbn(imag.s.lo, -ilogbw);
55
56  if (crt_isnan(real.s.hi) && crt_isnan(imag.s.hi)) {
57    DD aDD = {.ld = a};
58    DD bDD = {.ld = b};
59    DD rDD = {.ld = denom};
60
61    if ((rDD.s.hi == 0.0) && (!crt_isnan(aDD.s.hi) || !crt_isnan(bDD.s.hi))) {
62      real.s.hi = crt_copysign(CRT_INFINITY, cDD.s.hi) * aDD.s.hi;
63      real.s.lo = 0.0;
64      imag.s.hi = crt_copysign(CRT_INFINITY, cDD.s.hi) * bDD.s.hi;
65      imag.s.lo = 0.0;
66    }
67
68    else if ((crt_isinf(aDD.s.hi) || crt_isinf(bDD.s.hi)) &&
69             crt_isfinite(cDD.s.hi) && crt_isfinite(dDD.s.hi)) {
70      makeFinite(aDD);
71      makeFinite(bDD);
72      real.s.hi = CRT_INFINITY * (aDD.s.hi * cDD.s.hi + bDD.s.hi * dDD.s.hi);
73      real.s.lo = 0.0;
74      imag.s.hi = CRT_INFINITY * (bDD.s.hi * cDD.s.hi - aDD.s.hi * dDD.s.hi);
75      imag.s.lo = 0.0;
76    }
77
78    else if ((crt_isinf(cDD.s.hi) || crt_isinf(dDD.s.hi)) &&
79             crt_isfinite(aDD.s.hi) && crt_isfinite(bDD.s.hi)) {
80      makeFinite(cDD);
81      makeFinite(dDD);
82      real.s.hi =
83          crt_copysign(0.0, (aDD.s.hi * cDD.s.hi + bDD.s.hi * dDD.s.hi));
84      real.s.lo = 0.0;
85      imag.s.hi =
86          crt_copysign(0.0, (bDD.s.hi * cDD.s.hi - aDD.s.hi * dDD.s.hi));
87      imag.s.lo = 0.0;
88    }
89  }
90
91  long double _Complex z;
92  __real__ z = real.ld;
93  __imag__ z = imag.ld;
94
95  return z;
96}
97