mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
592f6ebc20
- 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
100 lines
4 KiB
C
100 lines
4 KiB
C
/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
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│ vi: set noet ft=c ts=8 sw=8 fenc=utf-8 :vi │
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╚──────────────────────────────────────────────────────────────────────────────╝
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│ │
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│ Musl Libc │
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│ Copyright © 2005-2014 Rich Felker, et al. │
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│ │
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│ Permission is hereby granted, free of charge, to any person obtaining │
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│ a copy of this software and associated documentation files (the │
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│ "Software"), to deal in the Software without restriction, including │
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│ without limitation the rights to use, copy, modify, merge, publish, │
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│ distribute, sublicense, and/or sell copies of the Software, and to │
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│ permit persons to whom the Software is furnished to do so, subject to │
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│ the following conditions: │
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│ │
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│ The above copyright notice and this permission notice shall be │
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│ included in all copies or substantial portions of the Software. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
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│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
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│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
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│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
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│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
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│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
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│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/math.h"
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__static_yoink("musl_libc_notice");
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#if FLT_EVAL_METHOD > 1U && LDBL_MANT_DIG == 64
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#define SPLIT (0x1p32 + 1)
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#else
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#define SPLIT (0x1p27 + 1)
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#endif
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static void sq(double_t *hi, double_t *lo, double x)
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{
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double_t xh, xl, xc;
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xc = (double_t)x*SPLIT;
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xh = x - xc + xc;
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xl = x - xh;
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*hi = (double_t)x*x;
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*lo = xh*xh - *hi + 2*xh*xl + xl*xl;
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}
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/**
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* Returns euclidean distance.
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*/
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double hypot(double x, double y)
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{
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union {double f; uint64_t i;} ux = {x}, uy = {y}, ut;
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int ex, ey;
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double_t hx, lx, hy, ly, z;
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/* arrange |x| >= |y| */
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ux.i &= -1ULL>>1;
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uy.i &= -1ULL>>1;
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if (ux.i < uy.i) {
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ut = ux;
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ux = uy;
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uy = ut;
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}
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/* special cases */
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ex = ux.i>>52;
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ey = uy.i>>52;
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x = ux.f;
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y = uy.f;
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/* note: hypot(inf,nan) == inf */
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if (ey == 0x7ff)
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return y;
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if (ex == 0x7ff || uy.i == 0)
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return x;
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/* note: hypot(x,y) ~= x + y*y/x/2 with inexact for small y/x */
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/* 64 difference is enough for ld80 double_t */
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if (ex - ey > 64)
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return x + y;
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/* precise sqrt argument in nearest rounding mode without overflow */
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/* xh*xh must not overflow and xl*xl must not underflow in sq */
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z = 1;
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if (ex > 0x3ff+510) {
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z = 0x1p700;
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x *= 0x1p-700;
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y *= 0x1p-700;
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} else if (ey < 0x3ff-450) {
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z = 0x1p-700;
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x *= 0x1p700;
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y *= 0x1p700;
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}
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sq(&hx, &lx, x);
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sq(&hy, &ly, y);
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return z*sqrt(ly+lx+hy+hx);
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}
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#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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__weak_reference(hypot, hypotl);
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#endif
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