view src/libm/s_cos.c @ 3415:1756b9569141

Adam Strzelecki to SDL Actually after my patch commited in r4928 MinGW configure seems to generate broken Makefile due MSYS bash bug. (Attaching cure/patch below) The problem is that: TEST=`echo 'one\\ two\\ three\\'` echo "$TEST" Should echo: one\ two\ three\ Does it on Linux, Mac.. all UNIX but not on MSYS (MinGW) which outputs: one\two\three\ (new lines removed, probably it doesn't like backslashes) Probably this bug should be submitted to MSYS team, but not waiting till MSYS gets it fixed (they have very slow release cycles) here goes simple cure... My patch simply replaces single quoted SED rules where we needed newlien injection with double quoted ones. Tested on Mac, Linux & MinGW. Please review it ASAP coz this may be showstopper for everybody compiling with MinGW.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 28 Oct 2009 04:27:50 +0000
parents dc1eb82ffdaa
children
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/* @(#)s_cos.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#if defined(LIBM_SCCS) && !defined(lint)
static const char rcsid[] =
    "$NetBSD: s_cos.c,v 1.7 1995/05/10 20:47:02 jtc Exp $";
#endif

/* cos(x)
 * Return cosine function of x.
 *
 * kernel function:
 *	__kernel_sin		... sine function on [-pi/4,pi/4]
 *	__kernel_cos		... cosine function on [-pi/4,pi/4]
 *	__ieee754_rem_pio2	... argument reduction routine
 *
 * Method.
 *      Let S,C and T denote the sin, cos and tan respectively on
 *	[-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
 *	in [-pi/4 , +pi/4], and let n = k mod 4.
 *	We have
 *
 *          n        sin(x)      cos(x)        tan(x)
 *     ----------------------------------------------------------
 *	    0	       S	   C		 T
 *	    1	       C	  -S		-1/T
 *	    2	      -S	  -C		 T
 *	    3	      -C	   S		-1/T
 *     ----------------------------------------------------------
 *
 * Special cases:
 *      Let trig be any of sin, cos, or tan.
 *      trig(+-INF)  is NaN, with signals;
 *      trig(NaN)    is that NaN;
 *
 * Accuracy:
 *	TRIG(x) returns trig(x) nearly rounded
 */

#include "math.h"
#include "math_private.h"

libm_hidden_proto(cos)
#ifdef __STDC__
     double cos(double x)
#else
     double cos(x)
     double x;
#endif
{
    double y[2], z = 0.0;
    int32_t n, ix;

    /* High word of x. */
    GET_HIGH_WORD(ix, x);

    /* |x| ~< pi/4 */
    ix &= 0x7fffffff;
    if (ix <= 0x3fe921fb)
        return __kernel_cos(x, z);

    /* cos(Inf or NaN) is NaN */
    else if (ix >= 0x7ff00000)
        return x - x;

    /* argument reduction needed */
    else {
        n = __ieee754_rem_pio2(x, y);
        switch (n & 3) {
        case 0:
            return __kernel_cos(y[0], y[1]);
        case 1:
            return -__kernel_sin(y[0], y[1], 1);
        case 2:
            return -__kernel_cos(y[0], y[1]);
        default:
            return __kernel_sin(y[0], y[1], 1);
        }
    }
}

libm_hidden_def(cos)