cosmopolitan/libc/tinymath/nextafter.c
Jōshin 2fc507c98f
Fix more vi modelines (#1006)
* modelines: tw -> sw

shiftwidth, not textwidth.

* space-surround modelines

* fix irregular modelines

* Fix modeline in titlegen.c
2023-12-13 02:28:11 -05:00

69 lines
3.4 KiB
C

/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
│ vi: set noet ft=c ts=8 sw=8 fenc=utf-8 :vi │
╚──────────────────────────────────────────────────────────────────────────────╝
│ │
│ Musl Libc │
│ Copyright © 2005-2014 Rich Felker, et al. │
│ │
│ Permission is hereby granted, free of charge, to any person obtaining │
│ a copy of this software and associated documentation files (the │
│ "Software"), to deal in the Software without restriction, including │
│ without limitation the rights to use, copy, modify, merge, publish, │
│ distribute, sublicense, and/or sell copies of the Software, and to │
│ permit persons to whom the Software is furnished to do so, subject to │
│ the following conditions: │
│ │
│ The above copyright notice and this permission notice shall be │
│ included in all copies or substantial portions of the Software. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
│ │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/math.h"
#include "libc/tinymath/feval.internal.h"
asm(".ident\t\"\\n\\n\
Musl libc (MIT License)\\n\
Copyright 2005-2014 Rich Felker, et. al.\"");
asm(".include \"libc/disclaimer.inc\"");
// clang-format off
double nextafter(double x, double y)
{
union {double f; uint64_t i;} ux={x}, uy={y};
uint64_t ax, ay;
int e;
if (isunordered(x, y))
return x + y;
if (ux.i == uy.i)
return y;
ax = ux.i & -1ULL/2;
ay = uy.i & -1ULL/2;
if (ax == 0) {
if (ay == 0)
return y;
ux.i = (uy.i & 1ULL<<63) | 1;
} else if (ax > ay || ((ux.i ^ uy.i) & 1ULL<<63))
ux.i--;
else
ux.i++;
e = ux.i >> 52 & 0x7ff;
/* raise overflow if ux.f is infinite and x is finite */
if (e == 0x7ff)
feval(x+x);
/* raise underflow if ux.f is subnormal or zero */
if (e == 0)
feval(x*x + ux.f*ux.f);
return ux.f;
}
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
__weak_reference(nextafter, nextafterl);
#endif