SDL  2.0
s_scalbn.c File Reference
#include "math_libm.h"
#include "math_private.h"
#include <limits.h>
+ Include dependency graph for s_scalbn.c:

Go to the source code of this file.

Functions

double scalbln (double x, long n)
 
 libm_hidden_def (scalbln)
 

Variables

static const double two54 = 1.80143985094819840000e+16
 
static const double twom54 = 5.55111512312578270212e-17
 
static const double huge = 1.0e+300
 
static const double tiny = 1.0e-300
 

Function Documentation

◆ libm_hidden_def()

libm_hidden_def ( scalbln  )

Definition at line 66 of file s_scalbn.c.

70 {
71  return scalbln(x, n);
72 }

References scalbln().

◆ scalbln()

double scalbln ( double  x,
long  n 
)

Definition at line 33 of file s_scalbn.c.

34 {
35  int32_t k, hx, lx;
36 
37  EXTRACT_WORDS(hx, lx, x);
38  k = (hx & 0x7ff00000) >> 20; /* extract exponent */
39  if (k == 0) { /* 0 or subnormal x */
40  if ((lx | (hx & 0x7fffffff)) == 0)
41  return x; /* +-0 */
42  x *= two54;
43  GET_HIGH_WORD(hx, x);
44  k = ((hx & 0x7ff00000) >> 20) - 54;
45  }
46  if (k == 0x7ff)
47  return x + x; /* NaN or Inf */
48  k = k + n;
49  if (k > 0x7fe)
50  return huge * copysign(huge, x); /* overflow */
51  if (n < -50000)
52  return tiny * copysign(tiny, x); /* underflow */
53  if (k > 0) { /* normal result */
54  SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
55  return x;
56  }
57  if (k <= -54) {
58  if (n > 50000) /* in case integer overflow in n+k */
59  return huge * copysign(huge, x); /* overflow */
60  return tiny * copysign(tiny, x); /* underflow */
61  }
62  k += 54; /* subnormal result */
63  SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
64  return x * twom54;
65 }

References copysign(), EXTRACT_WORDS, GET_HIGH_WORD, huge, k, SET_HIGH_WORD, tiny, two54, and twom54.

Referenced by libm_hidden_def().

Variable Documentation

◆ huge

const double huge = 1.0e+300
static

Definition at line 30 of file s_scalbn.c.

Referenced by scalbln().

◆ tiny

const double tiny = 1.0e-300
static

Definition at line 31 of file s_scalbn.c.

Referenced by scalbln().

◆ two54

const double two54 = 1.80143985094819840000e+16
static

Definition at line 28 of file s_scalbn.c.

Referenced by scalbln().

◆ twom54

const double twom54 = 5.55111512312578270212e-17
static

Definition at line 29 of file s_scalbn.c.

Referenced by scalbln().

scalbln
double scalbln(double x, long n)
Definition: s_scalbn.c:33
tiny
static const double tiny
Definition: s_scalbn.c:31
EXTRACT_WORDS
#define EXTRACT_WORDS(ix0, ix1, d)
Definition: math_private.h:99
n
GLdouble n
Definition: SDL_opengl_glext.h:1952
twom54
static const double twom54
Definition: s_scalbn.c:29
SET_HIGH_WORD
#define SET_HIGH_WORD(d, v)
Definition: math_private.h:137
two54
static const double two54
Definition: s_scalbn.c:28
x
GLint GLint GLint GLint GLint x
Definition: SDL_opengl.h:1574
int32_t
signed int int32_t
Definition: SDL_config_windows.h:62
huge
static const double huge
Definition: s_scalbn.c:30
k
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int int int return Display Window Cursor return Display Window return Display Drawable GC int int unsigned int unsigned int return Display Drawable GC int int _Xconst char int return Display Drawable GC int int unsigned int unsigned int return Display return Display Cursor return Display GC return XModifierKeymap return char Display Window int return Display return Display Atom return Display Window XWindowAttributes return Display Window return Display XEvent Bool(*) XPointer return Display Window Bool unsigned int int int Window Cursor Time return Display Window int return KeySym return Display _Xconst char Bool return Display _Xconst char return XKeyEvent char int KeySym XComposeStatus return Display int int int XVisualInfo return Display Window int int return _Xconst char return Display XEvent return Display Drawable GC XImage int int int int unsigned int unsigned int return Display Window Window Window int int int int unsigned int return Display Window Window int int return Display Window unsigned int unsigned int return Display Window Bool long XEvent return Display GC unsigned long return Display Window int Time return Display Window Window return Display Window unsigned long return Display Window XSizeHints Display Colormap XColor int return char int XTextProperty return XFontStruct _Xconst char int int int int XCharStruct return Display Window return Display Time return Display Colormap return Display Window Window int int unsigned int unsigned int int int return Display Window int return XExtensionInfo Display char XExtensionHooks int XPointer return XExtensionInfo XExtensionInfo Display return Display return Display unsigned long Display GC Display char long Display xReply int Bool return Display Bool return Display int SDL_X11_XESetEventToWireRetType return Display Window Window Window Window unsigned int return Display XShmSegmentInfo return Display Drawable GC XImage int int int int unsigned int unsigned int Boo k)
Definition: SDL_x11sym.h:213
copysign
double copysign(double x, double y)
Definition: s_copysign.c:21
GET_HIGH_WORD
#define GET_HIGH_WORD(i, d)
Definition: math_private.h:109