cosmopolitan/libc/tinymath/truncl.c
Justine Tunney 550b52abf6
Port a lot more code to AARCH64
- Introduce epoll_pwait()
- Rewrite -ftrapv and ffs() libraries in C code
- Use more FreeBSD code in math function library
- Get significantly more tests passing on qemu-aarch64
- Fix many Musl long double functions that were broken on AARCH64
2023-05-14 09:37:26 -07:00

73 lines
3.5 KiB
C

/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
│vi: set et ft=c ts=8 tw=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: │
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│ The above copyright notice and this permission notice shall be │
│ included in all copies or substantial portions of the Software. │
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│ 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/internal.h"
#include "libc/tinymath/ldshape.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
/**
* Rounds to integer, towards zero.
*/
long double truncl(long double x)
{
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
return trunc(x);
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
static const long double toint = 1/LDBL_EPSILON;
union ldshape u = {x};
int e = u.i.se & 0x7fff;
int s = u.i.se >> 15;
long double y;
if (e >= 0x3fff+LDBL_MANT_DIG-1)
return x;
if (e <= 0x3fff-1) {
FORCE_EVAL(x + 0x1p120f);
return x*0;
}
/* y = int(|x|) - |x|, where int(|x|) is an integer neighbor of |x| */
if (s)
x = -x;
y = x + toint - toint - x;
if (y > 0)
y -= 1;
x += y;
return s ? -x : x;
#else
#error "architecture unsupported"
#endif
}