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Diffstat (limited to 'Project/glm/ext/scalar_ulp.inl')
| -rw-r--r-- | Project/glm/ext/scalar_ulp.inl | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/Project/glm/ext/scalar_ulp.inl b/Project/glm/ext/scalar_ulp.inl new file mode 100644 index 0000000..308df15 --- /dev/null +++ b/Project/glm/ext/scalar_ulp.inl @@ -0,0 +1,284 @@ +/// 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. + +#include "../detail/type_float.hpp" +#include "../ext/scalar_constants.hpp" +#include <cmath> +#include <cfloat> + +#if(GLM_COMPILER & GLM_COMPILER_VC) +# pragma warning(push) +# pragma warning(disable : 4127) +#endif + +typedef union +{ + float value; + /* FIXME: Assumes 32 bit int. */ + unsigned int word; +} ieee_float_shape_type; + +typedef union +{ + double value; + struct + { + int lsw; + int msw; + } parts; +} ieee_double_shape_type; + +#define GLM_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) + +#define GLM_GET_FLOAT_WORD(i,d) \ + do { \ + ieee_float_shape_type gf_u; \ + gf_u.value = (d); \ + (i) = gf_u.word; \ + } while (0) + +#define GLM_SET_FLOAT_WORD(d,i) \ + do { \ + ieee_float_shape_type sf_u; \ + sf_u.word = (i); \ + (d) = sf_u.value; \ + } while (0) + +#define GLM_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) + +namespace glm{ +namespace detail +{ + GLM_FUNC_QUALIFIER float nextafterf(float x, float y) + { + volatile float t; + int hx, hy, ix, iy; + + GLM_GET_FLOAT_WORD(hx, x); + GLM_GET_FLOAT_WORD(hy, y); + ix = hx & 0x7fffffff; // |x| + iy = hy & 0x7fffffff; // |y| + + if((ix > 0x7f800000) || // x is nan + (iy > 0x7f800000)) // y is nan + return x + y; + if(abs(y - x) <= epsilon<float>()) + return y; // x=y, return y + if(ix == 0) + { // x == 0 + GLM_SET_FLOAT_WORD(x, (hy & 0x80000000) | 1);// return +-minsubnormal + t = x * x; + if(abs(t - x) <= epsilon<float>()) + return t; + else + return x; // raise underflow flag + } + if(hx >= 0) + { // x > 0 + if(hx > hy) // x > y, x -= ulp + hx -= 1; + else // x < y, x += ulp + hx += 1; + } + else + { // x < 0 + if(hy >= 0 || hx > hy) // x < y, x -= ulp + hx -= 1; + else // x > y, x += ulp + hx += 1; + } + hy = hx & 0x7f800000; + if(hy >= 0x7f800000) + return x + x; // overflow + if(hy < 0x00800000) // underflow + { + t = x * x; + if(abs(t - x) > epsilon<float>()) + { // raise underflow flag + GLM_SET_FLOAT_WORD(y, hx); + return y; + } + } + GLM_SET_FLOAT_WORD(x, hx); + return x; + } + + GLM_FUNC_QUALIFIER double nextafter(double x, double y) + { + volatile double t; + int hx, hy, ix, iy; + unsigned int lx, ly; + + GLM_EXTRACT_WORDS(hx, lx, x); + GLM_EXTRACT_WORDS(hy, ly, y); + ix = hx & 0x7fffffff; // |x| + iy = hy & 0x7fffffff; // |y| + + if(((ix >= 0x7ff00000) && ((ix - 0x7ff00000) | lx) != 0) || // x is nan + ((iy >= 0x7ff00000) && ((iy - 0x7ff00000) | ly) != 0)) // y is nan + return x + y; + if(abs(y - x) <= epsilon<double>()) + return y; // x=y, return y + if((ix | lx) == 0) + { // x == 0 + GLM_INSERT_WORDS(x, hy & 0x80000000, 1); // return +-minsubnormal + t = x * x; + if(abs(t - x) <= epsilon<double>()) + return t; + else + return x; // raise underflow flag + } + if(hx >= 0) { // x > 0 + if(hx > hy || ((hx == hy) && (lx > ly))) { // x > y, x -= ulp + if(lx == 0) hx -= 1; + lx -= 1; + } + else { // x < y, x += ulp + lx += 1; + if(lx == 0) hx += 1; + } + } + else { // x < 0 + if(hy >= 0 || hx > hy || ((hx == hy) && (lx > ly))){// x < y, x -= ulp + if(lx == 0) hx -= 1; + lx -= 1; + } + else { // x > y, x += ulp + lx += 1; + if(lx == 0) hx += 1; + } + } + hy = hx & 0x7ff00000; + if(hy >= 0x7ff00000) + return x + x; // overflow + if(hy < 0x00100000) + { // underflow + t = x * x; + if(abs(t - x) > epsilon<double>()) + { // raise underflow flag + GLM_INSERT_WORDS(y, hx, lx); + return y; + } + } + GLM_INSERT_WORDS(x, hx, lx); + return x; + } +}//namespace detail +}//namespace glm + +#if(GLM_COMPILER & GLM_COMPILER_VC) +# pragma warning(pop) +#endif + +namespace glm +{ + template<> + GLM_FUNC_QUALIFIER float nextFloat(float x) + { +# if GLM_HAS_CXX11_STL + return std::nextafter(x, std::numeric_limits<float>::max()); +# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS))) + return detail::nextafterf(x, FLT_MAX); +# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID) + return __builtin_nextafterf(x, FLT_MAX); +# else + return nextafterf(x, FLT_MAX); +# endif + } + + template<> + GLM_FUNC_QUALIFIER double nextFloat(double x) + { +# if GLM_HAS_CXX11_STL + return std::nextafter(x, std::numeric_limits<double>::max()); +# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS))) + return detail::nextafter(x, std::numeric_limits<double>::max()); +# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID) + return __builtin_nextafter(x, DBL_MAX); +# else + return nextafter(x, DBL_MAX); +# endif + } + + template<typename T> + GLM_FUNC_QUALIFIER T nextFloat(T x, int ULPs) + { + GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'next_float' only accept floating-point input"); + assert(ULPs >= 0); + + T temp = x; + for(int i = 0; i < ULPs; ++i) + temp = nextFloat(temp); + return temp; + } + + GLM_FUNC_QUALIFIER float prevFloat(float x) + { +# if GLM_HAS_CXX11_STL + return std::nextafter(x, std::numeric_limits<float>::min()); +# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS))) + return detail::nextafterf(x, FLT_MIN); +# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID) + return __builtin_nextafterf(x, FLT_MIN); +# else + return nextafterf(x, FLT_MIN); +# endif + } + + GLM_FUNC_QUALIFIER double prevFloat(double x) + { +# if GLM_HAS_CXX11_STL + return std::nextafter(x, std::numeric_limits<double>::min()); +# elif((GLM_COMPILER & GLM_COMPILER_VC) || ((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_PLATFORM & GLM_PLATFORM_WINDOWS))) + return _nextafter(x, DBL_MIN); +# elif(GLM_PLATFORM & GLM_PLATFORM_ANDROID) + return __builtin_nextafter(x, DBL_MIN); +# else + return nextafter(x, DBL_MIN); +# endif + } + + template<typename T> + GLM_FUNC_QUALIFIER T prevFloat(T x, int ULPs) + { + GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'prev_float' only accept floating-point input"); + assert(ULPs >= 0); + + T temp = x; + for(int i = 0; i < ULPs; ++i) + temp = prevFloat(temp); + return temp; + } + + GLM_FUNC_QUALIFIER int floatDistance(float x, float y) + { + detail::float_t<float> const a(x); + detail::float_t<float> const b(y); + + return abs(a.i - b.i); + } + + GLM_FUNC_QUALIFIER int64 floatDistance(double x, double y) + { + detail::float_t<double> const a(x); + detail::float_t<double> const b(y); + + return abs(a.i - b.i); + } +}//namespace glm |