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Diffstat (limited to 'newlib/libm/math/s_sin.c')
| -rw-r--r-- | newlib/libm/math/s_sin.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/newlib/libm/math/s_sin.c b/newlib/libm/math/s_sin.c new file mode 100644 index 00000000000..28259f378fe --- /dev/null +++ b/newlib/libm/math/s_sin.c @@ -0,0 +1,132 @@ + +/* @(#)s_sin.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. + * ==================================================== + */ + +/* +FUNCTION + <<sin>>, <<sinf>>, <<cos>>, <<cosf>>---sine or cosine +INDEX +sin +INDEX +sinf +INDEX +cos +INDEX +cosf +ANSI_SYNOPSIS + #include <math.h> + double sin(double <[x]>); + float sinf(float <[x]>); + double cos(double <[x]>); + float cosf(float <[x]>); + +TRAD_SYNOPSIS + #include <math.h> + double sin(<[x]>) + double <[x]>; + float sinf(<[x]>) + float <[x]>; + + double cos(<[x]>) + double <[x]>; + float cosf(<[x]>) + float <[x]>; + +DESCRIPTION + <<sin>> and <<cos>> compute (respectively) the sine and cosine + of the argument <[x]>. Angles are specified in radians. + + <<sinf>> and <<cosf>> are identical, save that they take and + return <<float>> values. + + +RETURNS + The sine or cosine of <[x]> is returned. + +PORTABILITY + <<sin>> and <<cos>> are ANSI C. + <<sinf>> and <<cosf>> are extensions. + +QUICKREF + sin ansi pure + sinf - pure +*/ + +/* sin(x) + * Return sine function of x. + * + * kernel function: + * __kernel_sin ... sine function on [-pi/4,pi/4] + * __kernel_cos ... cose 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 "fdlibm.h" + +#ifndef _DOUBLE_IS_32BITS + +#ifdef __STDC__ + double sin(double x) +#else + double sin(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_sin(x,z,0); + + /* sin(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_sin(y[0],y[1],1); + case 1: return __kernel_cos(y[0],y[1]); + case 2: return -__kernel_sin(y[0],y[1],1); + default: + return -__kernel_cos(y[0],y[1]); + } + } +} + +#endif /* _DOUBLE_IS_32BITS */ |