Mercurial > hg > CbC > CbC_gcc

comparison libquadmath/math/csqrtq.c @ 145:1830386684a0

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
parents 04ced10e8804
children
comparison
equal deleted inserted replaced
131:84e7813d76e9 145:1830386684a0
1 /* Complex square root of __float128 value. 1 /* Complex square root of a float type.
2 Copyright (C) 1997-2012 Free Software Foundation, Inc. 2 Copyright (C) 1997-2018 Free Software Foundation, Inc.
3 This file is part of the GNU C Library. 3 This file is part of the GNU C Library.
4 Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>. 4 Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>.
5 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. 5 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
6 6
7 The GNU C Library is free software; you can redistribute it and/or 7 The GNU C Library is free software; you can redistribute it and/or
18 License along with the GNU C Library; if not, see 18 License along with the GNU C Library; if not, see
19 <http://www.gnu.org/licenses/>. */ 19 <http://www.gnu.org/licenses/>. */
20 20
21 #include "quadmath-imp.h" 21 #include "quadmath-imp.h"
22 22
23 #ifdef HAVE_FENV_H
24 # include <fenv.h>
25 #endif
26
27
28 __complex128 23 __complex128
29 csqrtq (__complex128 x) 24 csqrtq (__complex128 x)
30 { 25 {
31 __complex128 res; 26 __complex128 res;
32 int rcls = fpclassifyq (__real__ x); 27 int rcls = fpclassifyq (__real__ x);
33 int icls = fpclassifyq (__imag__ x); 28 int icls = fpclassifyq (__imag__ x);
34 29
35 if (__builtin_expect (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE, 0)) 30 if (__glibc_unlikely (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE))
36 { 31 {
37 if (icls == QUADFP_INFINITE) 32 if (icls == QUADFP_INFINITE)
38 { 33 {
39 __real__ res = HUGE_VALQ; 34 __real__ res = HUGE_VALQ;
40 __imag__ res = __imag__ x; 35 __imag__ res = __imag__ x;
41 } 36 }
42 else if (rcls == QUADFP_INFINITE) 37 else if (rcls == QUADFP_INFINITE)
43 { 38 {
44 if (__real__ x < 0.0Q) 39 if (__real__ x < 0)
45 { 40 {
46 __real__ res = icls == QUADFP_NAN ? nanq ("") : 0; 41 __real__ res = icls == QUADFP_NAN ? nanq ("") : 0;
47 __imag__ res = copysignq (HUGE_VALQ, __imag__ x); 42 __imag__ res = copysignq (HUGE_VALQ, __imag__ x);
48 } 43 }
49 else 44 else
50 { 45 {
51 __real__ res = __real__ x; 46 __real__ res = __real__ x;
52 __imag__ res = (icls == QUADFP_NAN 47 __imag__ res = (icls == QUADFP_NAN
53 ? nanq ("") : copysignq (0.0Q, __imag__ x)); 48 ? nanq ("") : copysignq (0, __imag__ x));
54 } 49 }
55 } 50 }
56 else 51 else
57 { 52 {
58 __real__ res = nanq (""); 53 __real__ res = nanq ("");
59 __imag__ res = nanq (""); 54 __imag__ res = nanq ("");
60 } 55 }
61 } 56 }
62 else 57 else
63 { 58 {
64 if (__builtin_expect (icls == QUADFP_ZERO, 0)) 59 if (__glibc_unlikely (icls == QUADFP_ZERO))
65 { 60 {
66 if (__real__ x < 0.0Q) 61 if (__real__ x < 0)
67 { 62 {
68 __real__ res = 0.0Q; 63 __real__ res = 0;
69 __imag__ res = copysignq (sqrtq (-__real__ x), 64 __imag__ res = copysignq (sqrtq (-__real__ x), __imag__ x);
70 __imag__ x);
71 } 65 }
72 else 66 else
73 { 67 {
74 __real__ res = fabsq (sqrtq (__real__ x)); 68 __real__ res = fabsq (sqrtq (__real__ x));
75 __imag__ res = copysignq (0.0Q, __imag__ x); 69 __imag__ res = copysignq (0, __imag__ x);
76 } 70 }
77 } 71 }
78 else if (__builtin_expect (rcls == QUADFP_ZERO, 0)) 72 else if (__glibc_unlikely (rcls == QUADFP_ZERO))
79 { 73 {
80 __float128 r; 74 __float128 r;
81 if (fabsq (__imag__ x) >= 2.0Q * FLT128_MIN) 75 if (fabsq (__imag__ x) >= 2 * FLT128_MIN)
82 r = sqrtq (0.5Q * fabsq (__imag__ x)); 76 r = sqrtq (0.5Q * fabsq (__imag__ x));
83 else 77 else
84 r = 0.5Q * sqrtq (2.0Q * fabsq (__imag__ x)); 78 r = 0.5Q * sqrtq (2 * fabsq (__imag__ x));
85 79
86 __real__ res = r; 80 __real__ res = r;
87 __imag__ res = copysignq (r, __imag__ x); 81 __imag__ res = copysignq (r, __imag__ x);
88 } 82 }
89 else 83 else
90 { 84 {
91 __float128 d, r, s; 85 __float128 d, r, s;
92 int scale = 0; 86 int scale = 0;
93 87
94 if (fabsq (__real__ x) > FLT128_MAX / 4.0Q) 88 if (fabsq (__real__ x) > FLT128_MAX / 4)
95 { 89 {
96 scale = 1; 90 scale = 1;
97 __real__ x = scalbnq (__real__ x, -2 * scale); 91 __real__ x = scalbnq (__real__ x, -2 * scale);
98 __imag__ x = scalbnq (__imag__ x, -2 * scale); 92 __imag__ x = scalbnq (__imag__ x, -2 * scale);
99 } 93 }
100 else if (fabsq (__imag__ x) > FLT128_MAX / 4.0Q) 94 else if (fabsq (__imag__ x) > FLT128_MAX / 4)
101 { 95 {
102 scale = 1; 96 scale = 1;
103 if (fabsq (__real__ x) >= 4.0Q * FLT128_MIN) 97 if (fabsq (__real__ x) >= 4 * FLT128_MIN)
104 __real__ x = scalbnq (__real__ x, -2 * scale); 98 __real__ x = scalbnq (__real__ x, -2 * scale);
105 else 99 else
106 __real__ x = 0.0Q; 100 __real__ x = 0;
107 __imag__ x = scalbnq (__imag__ x, -2 * scale); 101 __imag__ x = scalbnq (__imag__ x, -2 * scale);
108 } 102 }
109 else if (fabsq (__real__ x) < FLT128_MIN 103 else if (fabsq (__real__ x) < 2 * FLT128_MIN
110 && fabsq (__imag__ x) < FLT128_MIN) 104 && fabsq (__imag__ x) < 2 * FLT128_MIN)
111 { 105 {
112 scale = -(FLT128_MANT_DIG / 2); 106 scale = -((FLT128_MANT_DIG + 1) / 2);
113 __real__ x = scalbnq (__real__ x, -2 * scale); 107 __real__ x = scalbnq (__real__ x, -2 * scale);
114 __imag__ x = scalbnq (__imag__ x, -2 * scale); 108 __imag__ x = scalbnq (__imag__ x, -2 * scale);
115 } 109 }
116 110
117 d = hypotq (__real__ x, __imag__ x); 111 d = hypotq (__real__ x, __imag__ x);
118 /* Use the identity 2 Re res Im res = Im x 112 /* Use the identity 2 Re res Im res = Im x
119 to avoid cancellation error in d +/- Re x. */ 113 to avoid cancellation error in d +/- Re x. */
120 if (__real__ x > 0) 114 if (__real__ x > 0)
121 { 115 {
122 r = sqrtq (0.5Q * (d + __real__ x)); 116 r = sqrtq (0.5Q * (d + __real__ x));
123 s = 0.5Q * (__imag__ x / r); 117 if (scale == 1 && fabsq (__imag__ x) < 1)
118 {
119 /* Avoid possible intermediate underflow. */
120 s = __imag__ x / r;
121 r = scalbnq (r, scale);
122 scale = 0;
123 }
124 else
125 s = 0.5Q * (__imag__ x / r);
124 } 126 }
125 else 127 else
126 { 128 {
127 s = sqrtq (0.5Q * (d - __real__ x)); 129 s = sqrtq (0.5Q * (d - __real__ x));
128 r = fabsq (0.5Q * (__imag__ x / s)); 130 if (scale == 1 && fabsq (__imag__ x) < 1)
131 {
132 /* Avoid possible intermediate underflow. */
133 r = fabsq (__imag__ x / s);
134 s = scalbnq (s, scale);
135 scale = 0;
136 }
137 else
138 r = fabsq (0.5Q * (__imag__ x / s));
129 } 139 }
130 140
131 if (scale) 141 if (scale)
132 { 142 {
133 r = scalbnq (r, scale); 143 r = scalbnq (r, scale);
134 s = scalbnq (s, scale); 144 s = scalbnq (s, scale);
135 } 145 }
136 146
147 math_check_force_underflow (r);
148 math_check_force_underflow (s);
149
137 __real__ res = r; 150 __real__ res = r;
138 __imag__ res = copysignq (s, __imag__ x); 151 __imag__ res = copysignq (s, __imag__ x);
139 } 152 }
140 } 153 }
141 154