Mercurial > sdl-ios-xcode
annotate src/libm/s_floor.c @ 3164:c5b2884c26b4
Added an ifdef so that if you
#define SDL_NO_COMPAT
before you include SDL.h then SDL_compat.h will never be included in your code.
This is useful for making sure that your code uses only SDL 1.3 features.
It is also handy for finding things that are in SDL_compat.h that belong elsewhere.
| author | Bob Pendleton <bob@pendleton.com> |
|---|---|
| date | Thu, 04 Jun 2009 21:00:45 +0000 |
| parents | dc1eb82ffdaa |
| children | 9ac6f0782dd6 |
| rev | line source |
|---|---|
| 2758 | 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) | |
| 3162 | 14 static const char rcsid[] = |
| 2758 | 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.h" | |
| 28 #include "math_private.h" | |
| 29 | |
| 30 #ifdef __STDC__ | |
| 31 static const double huge = 1.0e300; | |
| 32 #else | |
| 33 static double huge = 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 + 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 + 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 + 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)); | |
|
2765
f55c87ae336b
Final merge of Google Summer of Code 2008 work...
Sam Lantinga <slouken@libsdl.org>
parents:
2760
diff
changeset
|
84 if (j < (u_int32_t) i1) |
| 2758 | 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) |