340076f0f6
necessary, so that cosl(), sinl() and tanl() work on i386 even for naive callers. Suggested by: bde Reviewed by: bde Approved by: das (mentor)
96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
/*-
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* Copyright (c) 2007 Steven G. Kargl
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Limited testing on pseudorandom numbers drawn within [0:4e8] shows
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* an accuracy of <= 1.5 ULP where 247024 values of x out of 40 million
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* possibles resulted in tan(x) that exceeded 0.5 ULP (ie., 0.6%).
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*/
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#include <float.h>
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#ifdef __i386__
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#include <ieeefp.h>
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#endif
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#include "math.h"
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#include "math_private.h"
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#if LDBL_MANT_DIG == 64
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#include "../ld80/e_rem_pio2l.h"
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#elif LDBL_MANT_DIG == 113
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#include "../ld128/e_rem_pio2l.h"
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#else
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#error "Unsupported long double format"
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#endif
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long double
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tanl(long double x)
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{
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union IEEEl2bits z;
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int e0, s;
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long double y[2];
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long double hi, lo;
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z.e = x;
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s = z.bits.sign;
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z.bits.sign = 0;
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/* If x = +-0 or x is subnormal, then tan(x) = x. */
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if (z.bits.exp == 0)
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return (x);
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/* If x = NaN or Inf, then tan(x) = NaN. */
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if (z.bits.exp == 32767)
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return ((x - x) / (x - x));
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ENTERI();
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/* Optimize the case where x is already within range. */
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if (z.e < M_PI_4) {
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hi = __kernel_tanl(z.e, 0, 0);
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RETURNI(s ? -hi : hi);
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}
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e0 = __ieee754_rem_pio2l(x, y);
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hi = y[0];
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lo = y[1];
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switch (e0 & 3) {
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case 0:
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case 2:
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hi = __kernel_tanl(hi, lo, 0);
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break;
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case 1:
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case 3:
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hi = __kernel_tanl(hi, lo, 1);
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break;
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}
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RETURNI(hi);
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}
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