82 lines
2.6 KiB
C
82 lines
2.6 KiB
C
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/* Floating point consts needed by STL class mumeric_limits<float>
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and numeric_limits<double>. Also used as return values by nan, inf */
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#include <math.h>
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/*
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According to IEEE 754 a QNaN has exponent bits of all 1 values and
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initial significand bit of 1. A SNaN has has an exponent of all 1
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values and initial significand bit of 0 (with one or more other
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significand bits of 1). An Inf has significand of 0 and
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exponent of all 1 values. A denormal value has all exponent bits of 0.
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The following does _not_ follow those rules, but uses values
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equal to those exported from MS C++ runtime lib, msvcprt.dll
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for float and double. MSVC however, does not have long doubles.
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*/
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#define __DOUBLE_INF_REP { 0, 0, 0, 0x7ff0 }
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#define __DOUBLE_QNAN_REP { 0, 0, 0, 0xfff8 } /* { 0, 0, 0, 0x7ff8 } */
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#define __DOUBLE_SNAN_REP { 0, 0, 0, 0xfff0 } /* { 1, 0, 0, 0x7ff0 } */
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#define __DOUBLE_DENORM_REP {1, 0, 0, 0}
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#define D_NAN_MASK 0x7ff0000000000000LL /* this will mask NaN's and Inf's */
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#define __FLOAT_INF_REP { 0, 0x7f80 }
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#define __FLOAT_QNAN_REP { 0, 0xffc0 } /* { 0, 0x7fc0 } */
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#define __FLOAT_SNAN_REP { 0, 0xff80 } /* { 1, 0x7f80 } */
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#define __FLOAT_DENORM_REP {1,0}
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#define F_NAN_MASK 0x7f800000
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/* This assumes no implicit (hidden) bit in extended mode */
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#define __LONG_DOUBLE_INF_REP { 0, 0, 0, 0x8000, 0x7fff }
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#define __LONG_DOUBLE_QNAN_REP { 0, 0, 0, 0xc000, 0xffff }
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#define __LONG_DOUBLE_SNAN_REP { 0, 0, 0, 0x8000, 0xffff }
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#define __LONG_DOUBLE_DENORM_REP {1, 0, 0, 0, 0}
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union _ieee_rep
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{
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unsigned short rep[5];
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float float_val;
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double double_val;
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long double ldouble_val;
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} ;
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const union _ieee_rep __QNAN = { __DOUBLE_QNAN_REP };
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/*
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const union _ieee_rep __SNAN = { __DOUBLE_SNAN_REP };
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const union _ieee_rep __INF = { __DOUBLE_INF_REP };
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const union _ieee_rep __DENORM = { __DOUBLE_DENORM_REP };
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*/
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/* ISO C99 */
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#undef nan
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/* FIXME */
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double nan (const char * tagp __attribute__((unused)) )
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{ return __QNAN.double_val; }
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const union _ieee_rep __QNANF = { __FLOAT_QNAN_REP };
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/*
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const union _ieee_rep __SNANF = { __FLOAT_SNAN_REP };
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const union _ieee_rep __INFF = { __FLOAT_INF_REP };
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const union _ieee_rep __DENORMF = { __FLOAT_DENORM_REP };
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*/
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#undef nanf
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/* FIXME */
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float nanf(const char * tagp __attribute__((unused)) )
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{ return __QNANF.float_val;}
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const union _ieee_rep __QNANL = { __LONG_DOUBLE_QNAN_REP };
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/*
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const union _ieee_rep __SNANL = { __LONG_DOUBLE_SNAN_REP };
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const union _ieee_rep __INFL = { __LONG_DOUBLE_INF_REP };
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const union _ieee_rep __DENORML = { __LONG_DOUBLE_DENORM_REP };
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*/
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#undef nanl
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/* FIXME */
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long double nanl (const char * tagp __attribute__((unused)) )
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{ return __QNANL.ldouble_val;}
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