source: azure_iot_hub/trunk/musl-1.1.18/src/math/fmodl.c@ 388

Last change on this file since 388 was 388, checked in by coas-nagasima, 5 years ago

Azure IoT Hub Device C SDK を使ったサンプルの追加
  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
  • Property svn:mime-type set to text/x-csrc
File size: 1.9 KB
Line 
1#include "libm.h"
2
3#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
4long double fmodl(long double x, long double y)
5{
6 return fmod(x, y);
7}
8#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
9long double fmodl(long double x, long double y)
10{
11 union ldshape ux = {x}, uy = {y};
12 int ex = ux.i.se & 0x7fff;
13 int ey = uy.i.se & 0x7fff;
14 int sx = ux.i.se & 0x8000;
15
16 if (y == 0 || isnan(y) || ex == 0x7fff)
17 return (x*y)/(x*y);
18 ux.i.se = ex;
19 uy.i.se = ey;
20 if (ux.f <= uy.f) {
21 if (ux.f == uy.f)
22 return 0*x;
23 return x;
24 }
25
26 /* normalize x and y */
27 if (!ex) {
28 ux.f *= 0x1p120f;
29 ex = ux.i.se - 120;
30 }
31 if (!ey) {
32 uy.f *= 0x1p120f;
33 ey = uy.i.se - 120;
34 }
35
36 /* x mod y */
37#if LDBL_MANT_DIG == 64
38 uint64_t i, mx, my;
39 mx = ux.i.m;
40 my = uy.i.m;
41 for (; ex > ey; ex--) {
42 i = mx - my;
43 if (mx >= my) {
44 if (i == 0)
45 return 0*x;
46 mx = 2*i;
47 } else if (2*mx < mx) {
48 mx = 2*mx - my;
49 } else {
50 mx = 2*mx;
51 }
52 }
53 i = mx - my;
54 if (mx >= my) {
55 if (i == 0)
56 return 0*x;
57 mx = i;
58 }
59 for (; mx >> 63 == 0; mx *= 2, ex--);
60 ux.i.m = mx;
61#elif LDBL_MANT_DIG == 113
62 uint64_t hi, lo, xhi, xlo, yhi, ylo;
63 xhi = (ux.i2.hi & -1ULL>>16) | 1ULL<<48;
64 yhi = (uy.i2.hi & -1ULL>>16) | 1ULL<<48;
65 xlo = ux.i2.lo;
66 ylo = uy.i2.lo;
67 for (; ex > ey; ex--) {
68 hi = xhi - yhi;
69 lo = xlo - ylo;
70 if (xlo < ylo)
71 hi -= 1;
72 if (hi >> 63 == 0) {
73 if ((hi|lo) == 0)
74 return 0*x;
75 xhi = 2*hi + (lo>>63);
76 xlo = 2*lo;
77 } else {
78 xhi = 2*xhi + (xlo>>63);
79 xlo = 2*xlo;
80 }
81 }
82 hi = xhi - yhi;
83 lo = xlo - ylo;
84 if (xlo < ylo)
85 hi -= 1;
86 if (hi >> 63 == 0) {
87 if ((hi|lo) == 0)
88 return 0*x;
89 xhi = hi;
90 xlo = lo;
91 }
92 for (; xhi >> 48 == 0; xhi = 2*xhi + (xlo>>63), xlo = 2*xlo, ex--);
93 ux.i2.hi = xhi;
94 ux.i2.lo = xlo;
95#endif
96
97 /* scale result */
98 if (ex <= 0) {
99 ux.i.se = (ex+120)|sx;
100 ux.f *= 0x1p-120f;
101 } else
102 ux.i.se = ex|sx;
103 return ux.f;
104}
105#endif
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