Mercurial > sdl-ios-xcode
view src/libm/s_floor.c @ 5204:523409574510
Added an OpenGL ES 2.0 renderer, contributed by itsnotabigtruck
This compiles, but it untested.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 06 Feb 2011 00:00:13 -0800 |
parents | 9ac6f0782dd6 |
children |
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/* @(#)s_floor.c 5.1 93/09/24 */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice * is preserved. * ==================================================== */ #if defined(LIBM_SCCS) && !defined(lint) static const char rcsid[] = "$NetBSD: s_floor.c,v 1.8 1995/05/10 20:47:20 jtc Exp $"; #endif /* * floor(x) * Return x rounded toward -inf to integral value * Method: * Bit twiddling. * Exception: * Inexact flag raised if x not equal to floor(x). */ #include "math.h" #include "math_private.h" #ifdef __STDC__ static const double huge_val = 1.0e300; #else static double huge_val = 1.0e300; #endif libm_hidden_proto(floor) #ifdef __STDC__ double floor(double x) #else double floor(x) double x; #endif { int32_t i0, i1, j0; u_int32_t i, j; EXTRACT_WORDS(i0, i1, x); j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; if (j0 < 20) { if (j0 < 0) { /* raise inexact if x != 0 */ if (huge_val + x > 0.0) { /* return 0*sign(x) if |x|<1 */ if (i0 >= 0) { i0 = i1 = 0; } else if (((i0 & 0x7fffffff) | i1) != 0) { i0 = 0xbff00000; i1 = 0; } } } else { i = (0x000fffff) >> j0; if (((i0 & i) | i1) == 0) return x; /* x is integral */ if (huge_val + x > 0.0) { /* raise inexact flag */ if (i0 < 0) i0 += (0x00100000) >> j0; i0 &= (~i); i1 = 0; } } } else if (j0 > 51) { if (j0 == 0x400) return x + x; /* inf or NaN */ else return x; /* x is integral */ } else { i = ((u_int32_t) (0xffffffff)) >> (j0 - 20); if ((i1 & i) == 0) return x; /* x is integral */ if (huge_val + x > 0.0) { /* raise inexact flag */ if (i0 < 0) { if (j0 == 20) i0 += 1; else { j = i1 + (1 << (52 - j0)); if (j < (u_int32_t) i1) i0 += 1; /* got a carry */ i1 = j; } } i1 &= (~i); } } INSERT_WORDS(x, i0, i1); return x; } libm_hidden_def(floor)