cosmopolitan/libc/tinymath/trunc.c
Justine Tunney 592f6ebc20
Make quality improvements
- Write some more unit tests
- memcpy() on ARM is now faster
- Address the Musl complex math FIXME comments
- Some libm funcs like pow() now support setting errno
- Import the latest and greatest math functions from ARM
- Use more accurate atan2f() and log1pf() implementations
- atoi() and atol() will no longer saturate or clobber errno
2024-02-25 19:08:43 -08:00

84 lines
3.6 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. │
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│ Permission is hereby granted, free of charge, to any person obtaining │
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│ "Software"), to deal in the Software without restriction, including │
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│ 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 │
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╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/math.h"
#include "libc/tinymath/internal.h"
#ifndef __llvm__
#include "third_party/intel/smmintrin.internal.h"
#endif
__static_yoink("musl_libc_notice");
/**
* Rounds to integer, towards zero.
*/
double trunc(double x)
{
#ifdef __aarch64__
asm("frintz\t%d0,%d1" : "=w"(x) : "w"(x));
return x;
#elif defined(__powerpc64__) && defined(_ARCH_PWR5X)
asm("friz\t%0,%1" : "=d"(x) : "d"(x));
return x;
#elif defined(__s390x__) && (defined(__HTM__) || __ARCH__ >= 9)
asm("fidbra\t%0,5,%1,4" : "=f"(x) : "f"(x));
return x;
#elif defined(__x86_64__) && defined(__SSE4_1__) && !defined(__llvm__) && !defined(__chibicc__)
asm("roundsd\t%2,%1,%0"
: "=x"(x)
: "x"(x), "i"(_MM_FROUND_TO_ZERO | _MM_FROUND_NO_EXC));
return x;
#else
union {double f; uint64_t i;} u = {x};
int e = (int)(u.i >> 52 & 0x7ff) - 0x3ff + 12;
uint64_t m;
if (e >= 52 + 12)
return x;
if (e < 12)
e = 1;
m = -1ULL >> e;
if ((u.i & m) == 0)
return x;
FORCE_EVAL(x + 0x1p120f);
u.i &= ~m;
return u.f;
#endif /* __aarch64__ */
}
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
__weak_reference(trunc, truncl);
#endif