1#include "SDL_internal.h"
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/*
14 * floor(x)
15 * Return x rounded toward -inf to integral value
16 * Method:
17 * Bit twiddling.
18 * Exception:
19 * Inexact flag raised if x not equal to floor(x).
20 */
21
22/*#include <features.h>*/
23/* Prevent math.h from defining a colliding inline */
24#undef __USE_EXTERN_INLINES
25#include "math_libm.h"
26#include "math_private.h"
27
28#ifdef __WATCOMC__ /* Watcom defines huge=__huge */
29#undef huge
30#endif
31
32static const double huge = 1.0e300;
33
34double floor(double x)
35{
36 int32_t i0,i1,j0;
37 u_int32_t i,j;
38 EXTRACT_WORDS(i0,i1,x);
39 j0 = ((i0>>20)&0x7ff)-0x3ff;
40 if(j0<20) {
41 if(j0<0) { /* raise inexact if x != 0 */
42 if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
43 if(i0>=0) {i0=i1=0;}
44 else if(((i0&0x7fffffff)|i1)!=0)
45 { i0=0xbff00000;i1=0;}
46 }
47 } else {
48 i = (0x000fffff)>>j0;
49 if(((i0&i)|i1)==0) return x; /* x is integral */
50 if(huge+x>0.0) { /* raise inexact flag */
51 if(i0<0) i0 += (0x00100000)>>j0;
52 i0 &= (~i); i1=0;
53 }
54 }
55 } else if (j0>51) {
56 if(j0==0x400) return x+x; /* inf or NaN */
57 else return x; /* x is integral */
58 } else {
59 i = ((u_int32_t)(0xffffffff))>>(j0-20);
60 if((i1&i)==0) return x; /* x is integral */
61 if(huge+x>0.0) { /* raise inexact flag */
62 if(i0<0) {
63 if(j0==20) i0+=1;
64 else {
65 j = i1+(1<<(52-j0));
66 if(j<(u_int32_t)i1) i0 +=1 ; /* got a carry */
67 i1=j;
68 }
69 }
70 i1 &= (~i);
71 }
72 }
73 INSERT_WORDS(x,i0,i1);
74 return x;
75}
76libm_hidden_def(floor)
77