zenilib: zenilib/jni/external/sdl/src/libm/s_floor.c Source File

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s_floor.c
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1 /* @(#)s_floor.c 5.1 93/09/24 */
2 /*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12
13 #if defined(LIBM_SCCS) && !defined(lint)
14 static const char rcsid[] =
15 "$NetBSD: s_floor.c,v 1.8 1995/05/10 20:47:20 jtc Exp $";
16 #endif
17
18 /*
19 * floor(x)
20 * Return x rounded toward -inf to integral value
21 * Method:
22 * Bit twiddling.
23 * Exception:
24 * Inexact flag raised if x not equal to floor(x).
25 */
26
27 #include "math_libm.h"
28 #include "math_private.h"
29
30 #ifdef __STDC__
31 static const double huge_val = 1.0e300;
32 #else
33 static double huge_val = 1.0e300;
34 #endif
35
36 libm_hidden_proto(floor)
37 #ifdef __STDC__
38 double floor(double x)
39 #else
40 double floor(x)
41 double x;
42 #endif
43 {
44 int32_t i0, i1, j0;
45 u_int32_t i, j;
46 EXTRACT_WORDS(i0, i1, x);
47 j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
48 if (j0 < 20) {
49 if (j0 < 0) { /* raise inexact if x != 0 */
50 if (huge_val + x > 0.0) { /* return 0*sign(x) if |x|<1 */
51 if (i0 >= 0) {
52 i0 = i1 = 0;
53 } else if (((i0 & 0x7fffffff) | i1) != 0) {
54 i0 = 0xbff00000;
55 i1 = 0;
56 }
57 }
58 } else {
59 i = (0x000fffff) >> j0;
60 if (((i0 & i) | i1) == 0)
61 return x; /* x is integral */
62 if (huge_val + x > 0.0) { /* raise inexact flag */
63 if (i0 < 0)
64 i0 += (0x00100000) >> j0;
65 i0 &= (~i);
66 i1 = 0;
67 }
68 }
69 } else if (j0 > 51) {
70 if (j0 == 0x400)
71 return x + x; /* inf or NaN */
72 else
73 return x; /* x is integral */
74 } else {
75 i = ((u_int32_t) (0xffffffff)) >> (j0 - 20);
76 if ((i1 & i) == 0)
77 return x; /* x is integral */
78 if (huge_val + x > 0.0) { /* raise inexact flag */
79 if (i0 < 0) {
80 if (j0 == 20)
81 i0 += 1;
82 else {
83 j = i1 + (1 << (52 - j0));
84 if (j < (u_int32_t) i1)
85 i0 += 1; /* got a carry */
86 i1 = j;
87 }
88 }
89 i1 &= (~i);
90 }
91 }
92 INSERT_WORDS(x, i0, i1);
93 return x;
94 }
95
96 libm_hidden_def(floor)
x
EGLSurface EGLint x
Definition: eglext.h:293
j
int32_t j
Definition: e_log.c:102
int32_t
long int32_t
Definition: types.h:9
u_int32_t
unsigned int u_int32_t
Definition: math_private.h:29
huge_val
static double huge_val
Definition: s_floor.c:33
libm_hidden_def
#define libm_hidden_def(x)
Definition: math_private.h:26
EXTRACT_WORDS
#define EXTRACT_WORDS(ix0, ix1, d)
Definition: math_private.h:92
math_libm.h
floor
double floor(double x)
Definition: s_floor.c:40
i1
const GLubyte GLuint GLuint GLuint GLuint alpha GLboolean GLboolean GLboolean GLboolean alpha GLint GLint GLsizei GLsizei GLenum type GLenum GLint GLenum GLint GLint GLsizei GLsizei GLint border GLenum GLint GLint GLint GLint GLint GLsizei GLsizei height GLsizei GLsizei GLenum GLenum const GLvoid *pixels GLenum GLint i1
Definition: SDL_glfuncs.h:118
libm_hidden_proto
#define libm_hidden_proto(x)
Definition: math_private.h:25
INSERT_WORDS
INSERT_WORDS(z, ix0, ix1)
i
int i
Definition: pngrutil.c:1377
math_private.h