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

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Functions

double attribute_hidden __ieee754_fmod (double x, double y)
 

Variables

static const double one = 1.0
 
static const double Zero [] = {0.0, -0.0,}
 

Function Documentation

◆ __ieee754_fmod()

double attribute_hidden __ieee754_fmod ( double  x,
double  y 
)

Definition at line 23 of file e_fmod.c.

References __ieee754_fmod(), EXTRACT_WORDS, i, INSERT_WORDS, libm_hidden_def(), one, strong_alias, and Zero.

Referenced by __ieee754_fmod().

24 {
25  int32_t n,hx,hy,hz,ix,iy,sx,i;
26  u_int32_t lx,ly,lz;
27 
28  EXTRACT_WORDS(hx,lx,x);
29  EXTRACT_WORDS(hy,ly,y);
30  sx = hx&0x80000000; /* sign of x */
31  hx ^=sx; /* |x| */
32  hy &= 0x7fffffff; /* |y| */
33 
34  /* purge off exception values */
35  if((hy|ly)==0||(hx>=0x7ff00000)|| /* y=0,or x not finite */
36  ((hy|((ly|-(int32_t)ly)>>31))>0x7ff00000)) /* or y is NaN */
37  return (x*y)/(x*y);
38  if(hx<=hy) {
39  if((hx<hy)||(lx<ly)) return x; /* |x|<|y| return x */
40  if(lx==ly)
41  return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/
42  }
43 
44  /* determine ix = ilogb(x) */
45  if(hx<0x00100000) { /* subnormal x */
46  if(hx==0) {
47  for (ix = -1043, i=lx; i>0; i<<=1) ix -=1;
48  } else {
49  for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1;
50  }
51  } else ix = (hx>>20)-1023;
52 
53  /* determine iy = ilogb(y) */
54  if(hy<0x00100000) { /* subnormal y */
55  if(hy==0) {
56  for (iy = -1043, i=ly; i>0; i<<=1) iy -=1;
57  } else {
58  for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1;
59  }
60  } else iy = (hy>>20)-1023;
61 
62  /* set up {hx,lx}, {hy,ly} and align y to x */
63  if(ix >= -1022)
64  hx = 0x00100000|(0x000fffff&hx);
65  else { /* subnormal x, shift x to normal */
66  n = -1022-ix;
67  if(n<=31) {
68  hx = (hx<<n)|(lx>>(32-n));
69  lx <<= n;
70  } else {
71  hx = lx<<(n-32);
72  lx = 0;
73  }
74  }
75  if(iy >= -1022)
76  hy = 0x00100000|(0x000fffff&hy);
77  else { /* subnormal y, shift y to normal */
78  n = -1022-iy;
79  if(n<=31) {
80  hy = (hy<<n)|(ly>>(32-n));
81  ly <<= n;
82  } else {
83  hy = ly<<(n-32);
84  ly = 0;
85  }
86  }
87 
88  /* fix point fmod */
89  n = ix - iy;
90  while(n--) {
91  hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
92  if(hz<0){hx = hx+hx+(lx>>31); lx = lx+lx;}
93  else {
94  if((hz|lz)==0) /* return sign(x)*0 */
95  return Zero[(u_int32_t)sx>>31];
96  hx = hz+hz+(lz>>31); lx = lz+lz;
97  }
98  }
99  hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
100  if(hz>=0) {hx=hz;lx=lz;}
101 
102  /* convert back to floating value and restore the sign */
103  if((hx|lx)==0) /* return sign(x)*0 */
104  return Zero[(u_int32_t)sx>>31];
105  while(hx<0x00100000) { /* normalize x */
106  hx = hx+hx+(lx>>31); lx = lx+lx;
107  iy -= 1;
108  }
109  if(iy>= -1022) { /* normalize output */
110  hx = ((hx-0x00100000)|((iy+1023)<<20));
111  INSERT_WORDS(x,hx|sx,lx);
112  } else { /* subnormal output */
113  n = -1022 - iy;
114  if(n<=20) {
115  lx = (lx>>n)|((u_int32_t)hx<<(32-n));
116  hx >>= n;
117  } else if (n<=31) {
118  lx = (hx<<(32-n))|(lx>>n); hx = sx;
119  } else {
120  lx = hx>>(n-32); hx = sx;
121  }
122  INSERT_WORDS(x,hx|sx,lx);
123  x *= one; /* create necessary signal */
124  }
125  return x; /* exact output */
126 }
static const double Zero[]
Definition: e_fmod.c:21
GLint GLint GLint GLint GLint x
Definition: SDL_opengl.h:1574
signed int int32_t
unsigned int u_int32_t
Definition: math_private.h:31
#define EXTRACT_WORDS(ix0, ix1, d)
Definition: math_private.h:98
#define INSERT_WORDS(d, ix0, ix1)
Definition: math_private.h:126
GLint GLint GLint GLint GLint GLint y
Definition: SDL_opengl.h:1574
static const double one
Definition: e_fmod.c:21
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 in i)
Definition: SDL_x11sym.h:50
GLdouble n

Variable Documentation

◆ one

const double one = 1.0
static

Definition at line 21 of file e_fmod.c.

Referenced by __ieee754_fmod().

◆ Zero

const double Zero[] = {0.0, -0.0,}
static

Definition at line 21 of file e_fmod.c.

Referenced by __ieee754_fmod().