mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-05 19:21:05 +00:00
30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
161 lines
5.1 KiB
C
161 lines
5.1 KiB
C
/* s_nextafterl.c -- long double version of s_nextafter.c.
|
|
*/
|
|
|
|
/*
|
|
* ====================================================
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
|
* Permission to use, copy, modify, and distribute this
|
|
* software is freely granted, provided that this notice
|
|
* is preserved.
|
|
* ====================================================
|
|
*/
|
|
|
|
#if defined(LIBM_SCCS) && !defined(lint)
|
|
static char rcsid[] = "$NetBSD: $";
|
|
#endif
|
|
|
|
/* IEEE functions
|
|
* nextafterl(x,y)
|
|
* return the next machine floating-point number of x in the
|
|
* direction toward y.
|
|
* Special cases:
|
|
*/
|
|
|
|
#include <errno.h>
|
|
#include <float.h>
|
|
#include <math.h>
|
|
#include <math-barriers.h>
|
|
#include <math_private.h>
|
|
#include <math_ldbl_opt.h>
|
|
|
|
long double __nextafterl(long double x, long double y)
|
|
{
|
|
int64_t hx, hy, ihx, ihy, lx;
|
|
double xhi, xlo, yhi;
|
|
|
|
ldbl_unpack (x, &xhi, &xlo);
|
|
EXTRACT_WORDS64 (hx, xhi);
|
|
EXTRACT_WORDS64 (lx, xlo);
|
|
yhi = ldbl_high (y);
|
|
EXTRACT_WORDS64 (hy, yhi);
|
|
ihx = hx&0x7fffffffffffffffLL; /* |hx| */
|
|
ihy = hy&0x7fffffffffffffffLL; /* |hy| */
|
|
|
|
if((ihx>0x7ff0000000000000LL) || /* x is nan */
|
|
(ihy>0x7ff0000000000000LL)) /* y is nan */
|
|
return x+y; /* signal the nan */
|
|
if(x==y)
|
|
return y; /* x=y, return y */
|
|
if(ihx == 0) { /* x == 0 */
|
|
long double u; /* return +-minsubnormal */
|
|
hy = (hy & 0x8000000000000000ULL) | 1;
|
|
INSERT_WORDS64 (yhi, hy);
|
|
x = yhi;
|
|
u = math_opt_barrier (x);
|
|
u = u * u;
|
|
math_force_eval (u); /* raise underflow flag */
|
|
return x;
|
|
}
|
|
|
|
long double u;
|
|
if(x > y) { /* x > y, x -= ulp */
|
|
/* This isn't the largest magnitude correctly rounded
|
|
long double as you can see from the lowest mantissa
|
|
bit being zero. It is however the largest magnitude
|
|
long double with a 106 bit mantissa, and nextafterl
|
|
is insane with variable precision. So to make
|
|
nextafterl sane we assume 106 bit precision. */
|
|
if((hx==0xffefffffffffffffLL)&&(lx==0xfc8ffffffffffffeLL)) {
|
|
u = x+x; /* overflow, return -inf */
|
|
math_force_eval (u);
|
|
__set_errno (ERANGE);
|
|
return y;
|
|
}
|
|
if (hx >= 0x7ff0000000000000LL) {
|
|
u = 0x1.fffffffffffff7ffffffffffff8p+1023L;
|
|
return u;
|
|
}
|
|
if(ihx <= 0x0360000000000000LL) { /* x <= LDBL_MIN */
|
|
u = math_opt_barrier (x);
|
|
x -= LDBL_TRUE_MIN;
|
|
if (ihx < 0x0360000000000000LL
|
|
|| (hx > 0 && lx <= 0)
|
|
|| (hx < 0 && lx > 1)) {
|
|
u = u * u;
|
|
math_force_eval (u); /* raise underflow flag */
|
|
__set_errno (ERANGE);
|
|
}
|
|
/* Avoid returning -0 in FE_DOWNWARD mode. */
|
|
if (x == 0.0L)
|
|
return 0.0L;
|
|
return x;
|
|
}
|
|
/* If the high double is an exact power of two and the low
|
|
double is the opposite sign, then 1ulp is one less than
|
|
what we might determine from the high double. Similarly
|
|
if X is an exact power of two, and positive, because
|
|
making it a little smaller will result in the exponent
|
|
decreasing by one and normalisation of the mantissa. */
|
|
if ((hx & 0x000fffffffffffffLL) == 0
|
|
&& ((lx != 0 && (hx ^ lx) < 0)
|
|
|| (lx == 0 && hx >= 0)))
|
|
ihx -= 1LL << 52;
|
|
if (ihx < (106LL << 52)) { /* ulp will denormal */
|
|
INSERT_WORDS64 (yhi, ihx & (0x7ffLL<<52));
|
|
u = yhi * 0x1p-105;
|
|
} else {
|
|
INSERT_WORDS64 (yhi, (ihx & (0x7ffLL<<52))-(105LL<<52));
|
|
u = yhi;
|
|
}
|
|
return x - u;
|
|
} else { /* x < y, x += ulp */
|
|
if((hx==0x7fefffffffffffffLL)&&(lx==0x7c8ffffffffffffeLL)) {
|
|
u = x+x; /* overflow, return +inf */
|
|
math_force_eval (u);
|
|
__set_errno (ERANGE);
|
|
return y;
|
|
}
|
|
if ((uint64_t) hx >= 0xfff0000000000000ULL) {
|
|
u = -0x1.fffffffffffff7ffffffffffff8p+1023L;
|
|
return u;
|
|
}
|
|
if(ihx <= 0x0360000000000000LL) { /* x <= LDBL_MIN */
|
|
u = math_opt_barrier (x);
|
|
x += LDBL_TRUE_MIN;
|
|
if (ihx < 0x0360000000000000LL
|
|
|| (hx > 0 && lx < 0 && lx != 0x8000000000000001LL)
|
|
|| (hx < 0 && lx >= 0)) {
|
|
u = u * u;
|
|
math_force_eval (u); /* raise underflow flag */
|
|
__set_errno (ERANGE);
|
|
}
|
|
if (x == 0.0L) /* handle negative LDBL_TRUE_MIN case */
|
|
x = -0.0L;
|
|
return x;
|
|
}
|
|
/* If the high double is an exact power of two and the low
|
|
double is the opposite sign, then 1ulp is one less than
|
|
what we might determine from the high double. Similarly
|
|
if X is an exact power of two, and negative, because
|
|
making it a little larger will result in the exponent
|
|
decreasing by one and normalisation of the mantissa. */
|
|
if ((hx & 0x000fffffffffffffLL) == 0
|
|
&& ((lx != 0 && (hx ^ lx) < 0)
|
|
|| (lx == 0 && hx < 0)))
|
|
ihx -= 1LL << 52;
|
|
if (ihx < (106LL << 52)) { /* ulp will denormal */
|
|
INSERT_WORDS64 (yhi, ihx & (0x7ffLL<<52));
|
|
u = yhi * 0x1p-105;
|
|
} else {
|
|
INSERT_WORDS64 (yhi, (ihx & (0x7ffLL<<52))-(105LL<<52));
|
|
u = yhi;
|
|
}
|
|
return x + u;
|
|
}
|
|
}
|
|
strong_alias (__nextafterl, __nexttowardl)
|
|
long_double_symbol (libm, __nextafterl, nextafterl);
|
|
long_double_symbol (libm, __nexttowardl, nexttowardl);
|