73 lines
2.1 KiB
C
73 lines
2.1 KiB
C
/* s_tanf.c -- float version of s_tan.c.
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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* Optimized by Bruce D. Evans.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include "cdefs-compat.h"
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//__FBSDID("$FreeBSD: src/lib/msun/src/s_tanf.c,v 1.17 2008/02/25 22:19:17 bde Exp $");
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#include <float.h>
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#include <openlibm_math.h>
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//#define INLINE_KERNEL_TANDF
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//#define INLINE_REM_PIO2F
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#include "math_private.h"
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//#include "e_rem_pio2f.c"
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//#include "k_tanf.c"
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/* Small multiples of pi/2 rounded to double precision. */
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static const double
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t1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
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t2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
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t3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
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t4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
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OLM_DLLEXPORT float
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tanf(float x)
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{
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double y;
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int32_t n, hx, ix;
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GET_FLOAT_WORD(hx,x);
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ix = hx & 0x7fffffff;
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if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */
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if(ix<0x39800000) /* |x| < 2**-12 */
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if(((int)x)==0) return x; /* x with inexact if x != 0 */
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return __kernel_tandf(x,1);
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}
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if(ix<=0x407b53d1) { /* |x| ~<= 5*pi/4 */
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if(ix<=0x4016cbe3) /* |x| ~<= 3pi/4 */
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return __kernel_tandf(x + (hx>0 ? -t1pio2 : t1pio2), -1);
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else
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return __kernel_tandf(x + (hx>0 ? -t2pio2 : t2pio2), 1);
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}
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if(ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */
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if(ix<=0x40afeddf) /* |x| ~<= 7*pi/4 */
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return __kernel_tandf(x + (hx>0 ? -t3pio2 : t3pio2), -1);
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else
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return __kernel_tandf(x + (hx>0 ? -t4pio2 : t4pio2), 1);
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}
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/* tan(Inf or NaN) is NaN */
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else if (ix>=0x7f800000) return x-x;
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/* general argument reduction needed */
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else {
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n = __ieee754_rem_pio2f(x,&y);
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/* integer parameter: 1 -- n even; -1 -- n odd */
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return __kernel_tandf(y,1-((n&1)<<1));
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}
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}
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