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

     1  #include "libm.h"
     2  
     3  #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
     4  long double floorl(long double x)
     5  {
     6  	return floor(x);
     7  }
     8  #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
     9  
    10  static const long double toint = 1/LDBL_EPSILON;
    11  
    12  long double floorl(long double x)
    13  {
    14  	union ldshape u = {x};
    15  	int e = u.i.se & 0x7fff;
    16  	long double y;
    17  
    18  	if (e >= 0x3fff+LDBL_MANT_DIG-1 || x == 0)
    19  		return x;
    20  	/* y = int(x) - x, where int(x) is an integer neighbor of x */
    21  	if (u.i.se >> 15)
    22  		y = x - toint + toint - x;
    23  	else
    24  		y = x + toint - toint - x;
    25  	/* special case because of non-nearest rounding modes */
    26  	if (e <= 0x3fff-1) {
    27  		FORCE_EVAL(y);
    28  		return u.i.se >> 15 ? -1 : 0;
    29  	}
    30  	if (y > 0)
    31  		return x + y - 1;
    32  	return x + y;
    33  }
    34  #endif