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

     1  #include "libm.h"
     2  
     3  #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
     4  long double nextafterl(long double x, long double y)
     5  {
     6  	return nextafter(x, y);
     7  }
     8  #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
     9  long double nextafterl(long double x, long double y)
    10  {
    11  	union ldshape ux, uy;
    12  
    13  	if (isnan(x) || isnan(y))
    14  		return x + y;
    15  	if (x == y)
    16  		return y;
    17  	ux.f = x;
    18  	if (x == 0) {
    19  		uy.f = y;
    20  		ux.i.m = 1;
    21  		ux.i.se = uy.i.se & 0x8000;
    22  	} else if ((x < y) == !(ux.i.se & 0x8000)) {
    23  		ux.i.m++;
    24  		if (ux.i.m << 1 == 0) {
    25  			ux.i.m = 1ULL << 63;
    26  			ux.i.se++;
    27  		}
    28  	} else {
    29  		if (ux.i.m << 1 == 0) {
    30  			ux.i.se--;
    31  			if (ux.i.se)
    32  				ux.i.m = 0;
    33  		}
    34  		ux.i.m--;
    35  	}
    36  	/* raise overflow if ux is infinite and x is finite */
    37  	if ((ux.i.se & 0x7fff) == 0x7fff)
    38  		return x + x;
    39  	/* raise underflow if ux is subnormal or zero */
    40  	if ((ux.i.se & 0x7fff) == 0)
    41  		FORCE_EVAL(x*x + ux.f*ux.f);
    42  	return ux.f;
    43  }
    44  #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
    45  long double nextafterl(long double x, long double y)
    46  {
    47  	union ldshape ux, uy;
    48  
    49  	if (isnan(x) || isnan(y))
    50  		return x + y;
    51  	if (x == y)
    52  		return y;
    53  	ux.f = x;
    54  	if (x == 0) {
    55  		uy.f = y;
    56  		ux.i.lo = 1;
    57  		ux.i.se = uy.i.se & 0x8000;
    58  	} else if ((x < y) == !(ux.i.se & 0x8000)) {
    59  		ux.i2.lo++;
    60  		if (ux.i2.lo == 0)
    61  			ux.i2.hi++;
    62  	} else {
    63  		if (ux.i2.lo == 0)
    64  			ux.i2.hi--;
    65  		ux.i2.lo--;
    66  	}
    67  	/* raise overflow if ux is infinite and x is finite */
    68  	if ((ux.i.se & 0x7fff) == 0x7fff)
    69  		return x + x;
    70  	/* raise underflow if ux is subnormal or zero */
    71  	if ((ux.i.se & 0x7fff) == 0)
    72  		FORCE_EVAL(x*x + ux.f*ux.f);
    73  	return ux.f;
    74  }
    75  #endif