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/*
* 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 <math.h>
#include <inttypes.h>
#include "local.h"
union fshape {
float value;
uint32_t bits;
};
// This is only necessary because the implementation of isnan only works
// properly when long double == double.
// See: https://sourceware.org/ml/newlib/2014/msg00684.html
#ifdef _LDBL_EQ_DBL
float
nexttowardf (float x, long double y)
{
union fshape ux;
uint32_t e;
if (isnan(x) || isnan(y))
return x + y;
if (x == y)
return y;
ux.value = x;
if (x == 0) {
ux.bits = 1;
if (signbit(y))
ux.bits |= 0x80000000;
} else if (x < y) {
if (signbit(x))
ux.bits--;
else
ux.bits++;
} else {
if (signbit(x))
ux.bits++;
else
ux.bits--;
}
e = ux.bits & 0x7f800000;
/* raise overflow if ux.value is infinite and x is finite */
if (e == 0x7f800000) {
volatile float force_eval;
force_eval = x + x;
}
/* raise underflow if ux.value is subnormal or zero */
if (e == 0) {
volatile float force_eval;
force_eval = x*x + ux.value*ux.value;
}
return ux.value;
}
#endif // _LDBL_EQ_DBL
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