Mercurial > sdl-ios-xcode
annotate src/libm/s_floor.c @ 3468:789b97008d8a
My first OpenGL shader! Momma will be so proud!
This shader implements the software renderer mask semantics where the source pixel is multiplied by the color and alpha modulation values and then any pixel with non-zero alpha is fully opaque.
The OpenGL renderer on Mac OS X now passes all the automated render tests! :)
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 21 Nov 2009 05:29:31 +0000 |
| parents | 9ac6f0782dd6 |
| children |
| 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__ | |
| 3337 | 31 static const double huge_val = 1.0e300; |
| 2758 | 32 #else |
| 3337 | 33 static double huge_val = 1.0e300; |
| 2758 | 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 */ | |
| 3337 | 50 if (huge_val + x > 0.0) { /* return 0*sign(x) if |x|<1 */ |
| 2758 | 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 */ | |
| 3337 | 62 if (huge_val + x > 0.0) { /* raise inexact flag */ |
| 2758 | 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 */ | |
| 3337 | 78 if (huge_val + x > 0.0) { /* raise inexact flag */ |
| 2758 | 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) |