github.com/afumu/libc@v0.0.6/musl/src/math/__fpclassifyl.c (about)

     1  #include "libm.h"
     2  
     3  #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
     4  int __fpclassifyl(long double x)
     5  {
     6  	return __fpclassify(x);
     7  }
     8  #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
     9  int __fpclassifyl(long double x)
    10  {
    11  	union ldshape u = {x};
    12  	int e = u.i.se & 0x7fff;
    13  	int msb = u.i.m>>63;
    14  	if (!e && !msb)
    15  		return u.i.m ? FP_SUBNORMAL : FP_ZERO;
    16  	if (e == 0x7fff) {
    17  		/* The x86 variant of 80-bit extended precision only admits
    18  		 * one representation of each infinity, with the mantissa msb
    19  		 * necessarily set. The version with it clear is invalid/nan.
    20  		 * The m68k variant, however, allows either, and tooling uses
    21  		 * the version with it clear. */
    22  		if (__BYTE_ORDER == __LITTLE_ENDIAN && !msb)
    23  			return FP_NAN;
    24  		return u.i.m << 1 ? FP_NAN : FP_INFINITE;
    25  	}
    26  	if (!msb)
    27  		return FP_NAN;
    28  	return FP_NORMAL;
    29  }
    30  #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
    31  int __fpclassifyl(long double x)
    32  {
    33  	union ldshape u = {x};
    34  	int e = u.i.se & 0x7fff;
    35  	u.i.se = 0;
    36  	if (!e)
    37  		return u.i2.lo | u.i2.hi ? FP_SUBNORMAL : FP_ZERO;
    38  	if (e == 0x7fff)
    39  		return u.i2.lo | u.i2.hi ? FP_NAN : FP_INFINITE;
    40  	return FP_NORMAL;
    41  }
    42  #endif