SDL  2.0
k_tan.c File Reference
#include "math_libm.h"
#include "math_private.h"
+ Include dependency graph for k_tan.c:

Go to the source code of this file.

Functions

double attribute_hidden __kernel_tan (double x, double y, int iy)
 

Variables

static const double one = 1.00000000000000000000e+00
 
static const double pio4 = 7.85398163397448278999e-01
 
static const double pio4lo = 3.06161699786838301793e-17
 
static const double T []
 

Function Documentation

◆ __kernel_tan()

double attribute_hidden __kernel_tan ( double  x,
double  y,
int  iy 
)

Definition at line 69 of file k_tan.c.

References fabs(), GET_HIGH_WORD, GET_LOW_WORD, one, pio4, pio4lo, SET_LOW_WORD, and T.

Referenced by tan().

70 {
71  double z,r,v,w,s;
72  int32_t ix,hx;
73  GET_HIGH_WORD(hx,x);
74  ix = hx&0x7fffffff; /* high word of |x| */
75  if(ix<0x3e300000) /* x < 2**-28 */
76  {if((int)x==0) { /* generate inexact */
77  u_int32_t low;
78  GET_LOW_WORD(low,x);
79  if(((ix|low)|(iy+1))==0) return one/fabs(x);
80  else return (iy==1)? x: -one/x;
81  }
82  }
83  if(ix>=0x3FE59428) { /* |x|>=0.6744 */
84  if(hx<0) {x = -x; y = -y;}
85  z = pio4-x;
86  w = pio4lo-y;
87  x = z+w; y = 0.0;
88  }
89  z = x*x;
90  w = z*z;
91  /* Break x^5*(T[1]+x^2*T[2]+...) into
92  * x^5(T[1]+x^4*T[3]+...+x^20*T[11]) +
93  * x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12]))
94  */
95  r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11]))));
96  v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12])))));
97  s = z*x;
98  r = y + z*(s*(r+v)+y);
99  r += T[0]*s;
100  w = x+r;
101  if(ix>=0x3FE59428) {
102  v = (double)iy;
103  return (double)(1-((hx>>30)&2))*(v-2.0*(x-(w*w/(w+v)-r)));
104  }
105  if(iy==1) return w;
106  else { /* if allow error up to 2 ulp,
107  simply return -1.0/(x+r) here */
108  /* compute -1.0/(x+r) accurately */
109  double a,t;
110  z = w;
111  SET_LOW_WORD(z,0);
112  v = r-(z - x); /* z+v = r+x */
113  t = a = -1.0/w; /* a = -1.0/w */
114  SET_LOW_WORD(t,0);
115  s = 1.0+t*z;
116  return t+a*(s+t*v);
117  }
118 }
#define GET_HIGH_WORD(i, d)
Definition: math_private.h:108
GLdouble GLdouble GLdouble r
Definition: SDL_opengl.h:2079
GLdouble GLdouble z
GLdouble s
Definition: SDL_opengl.h:2063
static const double pio4lo
Definition: k_tan.c:52
const GLdouble * v
Definition: SDL_opengl.h:2064
GLint GLint GLint GLint GLint x
Definition: SDL_opengl.h:1574
signed int int32_t
static const double T[]
Definition: k_tan.c:53
unsigned int u_int32_t
Definition: math_private.h:31
#define SET_LOW_WORD(d, v)
Definition: math_private.h:146
GLubyte GLubyte GLubyte GLubyte w
GLint GLint GLint GLint GLint GLint y
Definition: SDL_opengl.h:1574
#define GET_LOW_WORD(i, d)
Definition: math_private.h:117
static const double pio4
Definition: k_tan.c:51
static const double one
Definition: k_tan.c:50
GLboolean GLboolean GLboolean GLboolean a
double fabs(double x)
Definition: s_fabs.c:22
GLdouble GLdouble t
Definition: SDL_opengl.h:2071

Variable Documentation

◆ one

const double one = 1.00000000000000000000e+00
static

Definition at line 50 of file k_tan.c.

Referenced by __kernel_tan().

◆ pio4

const double pio4 = 7.85398163397448278999e-01
static

Definition at line 51 of file k_tan.c.

Referenced by __kernel_tan().

◆ pio4lo

const double pio4lo = 3.06161699786838301793e-17
static

Definition at line 52 of file k_tan.c.

Referenced by __kernel_tan().

◆ T

const double T[]
static
Initial value:
= {
3.33333333333334091986e-01,
1.33333333333201242699e-01,
5.39682539762260521377e-02,
2.18694882948595424599e-02,
8.86323982359930005737e-03,
3.59207910759131235356e-03,
1.45620945432529025516e-03,
5.88041240820264096874e-04,
2.46463134818469906812e-04,
7.81794442939557092300e-05,
7.14072491382608190305e-05,
-1.85586374855275456654e-05,
2.59073051863633712884e-05,
}

Definition at line 53 of file k_tan.c.

Referenced by __kernel_tan(), and runAdder().