Mercurial > sdl-ios-xcode
view src/video/math_private.h @ 2198:fe19afb86473
Split acinclude.m4 into its component parts for easy updating
author | Sam Lantinga <slouken@libsdl.org> |
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date | Sun, 15 Jul 2007 01:51:11 +0000 |
parents | c121d94672cb |
children | 2a3ec308d995 |
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/* * ==================================================== * 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. * ==================================================== */ /* * from: @(#)fdlibm.h 5.1 93/09/24 * $Id$ */ #ifndef _MATH_PRIVATE_H_ #define _MATH_PRIVATE_H_ #include "SDL_name.h" #include "SDL_endian.h" #define huge really_big /* huge is a reserved keyword in VC++ 6.0 */ #define u_int32_t uint32_t /* The original fdlibm code used statements like: n0 = ((*(int*)&one)>>29)^1; * index of high word * ix0 = *(n0+(int*)&x); * high word of x * ix1 = *((1-n0)+(int*)&x); * low word of x * to dig two 32 bit words out of the 64 bit IEEE floating point value. That is non-ANSI, and, moreover, the gcc instruction scheduler gets it wrong. We instead use the following macros. Unlike the original code, we determine the endianness at compile time, not at run time; I don't see much benefit to selecting endianness at run time. */ /* A union which permits us to convert between a double and two 32 bit ints. */ /* * Math on arm is special: * For FPA, float words are always big-endian. * For VFP, floats words follow the memory system mode. */ #if (SDL_BYTEORDER == SDL_BIG_ENDIAN) || \ (!defined(__VFP_FP__) && (defined(__arm__) || defined(__thumb__))) typedef union { double value; struct { u_int32_t msw; u_int32_t lsw; } parts; } ieee_double_shape_type; #else typedef union { double value; struct { u_int32_t lsw; u_int32_t msw; } parts; } ieee_double_shape_type; #endif /* Get two 32 bit ints from a double. */ #define EXTRACT_WORDS(ix0,ix1,d) \ do { \ ieee_double_shape_type ew_u; \ ew_u.value = (d); \ (ix0) = ew_u.parts.msw; \ (ix1) = ew_u.parts.lsw; \ } while (0) /* Get the more significant 32 bit int from a double. */ #define GET_HIGH_WORD(i,d) \ do { \ ieee_double_shape_type gh_u; \ gh_u.value = (d); \ (i) = gh_u.parts.msw; \ } while (0) /* Get the less significant 32 bit int from a double. */ #define GET_LOW_WORD(i,d) \ do { \ ieee_double_shape_type gl_u; \ gl_u.value = (d); \ (i) = gl_u.parts.lsw; \ } while (0) /* Set a double from two 32 bit ints. */ #define INSERT_WORDS(d,ix0,ix1) \ do { \ ieee_double_shape_type iw_u; \ iw_u.parts.msw = (ix0); \ iw_u.parts.lsw = (ix1); \ (d) = iw_u.value; \ } while (0) /* Set the more significant 32 bits of a double from an int. */ #define SET_HIGH_WORD(d,v) \ do { \ ieee_double_shape_type sh_u; \ sh_u.value = (d); \ sh_u.parts.msw = (v); \ (d) = sh_u.value; \ } while (0) /* Set the less significant 32 bits of a double from an int. */ #define SET_LOW_WORD(d,v) \ do { \ ieee_double_shape_type sl_u; \ sl_u.value = (d); \ sl_u.parts.lsw = (v); \ (d) = sl_u.value; \ } while (0) /* A union which permits us to convert between a float and a 32 bit int. */ typedef union { float value; u_int32_t word; } ieee_float_shape_type; /* Get a 32 bit int from a float. */ #define GET_FLOAT_WORD(i,d) \ do { \ ieee_float_shape_type gf_u; \ gf_u.value = (d); \ (i) = gf_u.word; \ } while (0) /* Set a float from a 32 bit int. */ #define SET_FLOAT_WORD(d,i) \ do { \ ieee_float_shape_type sf_u; \ sf_u.word = (i); \ (d) = sf_u.value; \ } while (0) #ifdef __STDC__ static const double #else static double #endif zero = 0.0, one = 1.0, two = 2.0, two53 = 9007199254740992.0, /* 0x43400000, 0x00000000 */ two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */ twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */ huge = 1.0e+300, tiny = 1.0e-300; #endif /* _MATH_PRIVATE_H_ */ /* vi: set ts=4 sw=4 expandtab: */