X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fcosl.c;h=d23c15f0298956b63f272973ec0b377ce113ea97;hb=a39d56cfe7d904b61aba940b20de06b94b6a60f8;hp=3c28f77c6db93ad510b0580ac689ab26151685f0;hpb=e1123c2f4fedae90435426a82a05cf2e3233e97d;p=gnulib.git diff --git a/lib/cosl.c b/lib/cosl.c index 3c28f77c6..d23c15f02 100644 --- a/lib/cosl.c +++ b/lib/cosl.c @@ -22,22 +22,22 @@ * Return sine function of x. * * kernel function: - * __kernel_sinl ... sine function on [-pi/4,pi/4] - * __kernel_cosl ... cose function on [-pi/4,pi/4] - * __ieee754_rem_pio2l ... argument reduction routine + * __kernel_sinl ... sine function on [-pi/4,pi/4] + * __kernel_cosl ... cose function on [-pi/4,pi/4] + * __ieee754_rem_pio2l ... 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 + * [-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 + * 0 S C T + * 1 C -S -1/T + * 2 -S -C T + * 3 -C S -1/T * ---------------------------------------------------------- * * Special cases: @@ -46,53 +46,59 @@ * trig(NaN) is that NaN; * * Accuracy: - * TRIG(x) returns trig(x) nearly rounded + * TRIG(x) returns trig(x) nearly rounded */ #include "trigl.h" -#ifdef HAVE_SINL -#include "trigl.c" -#include "sincosl.c" -#endif -long double cosl(long double x) +long double +cosl (long double x) { - long double y[2],z=0.0L; - int n; + long double y[2],z=0.0L; + int n; + + /* cosl(NaN) is NaN */ + if (isnanl (x)) + return x; - /* |x| ~< pi/4 */ - if(x >= -0.7853981633974483096156608458198757210492 && - x <= 0.7853981633974483096156608458198757210492) - return kernel_cosl(x, z); + /* |x| ~< pi/4 */ + if (x >= -0.7853981633974483096156608458198757210492 + && x <= 0.7853981633974483096156608458198757210492) + return kernel_cosl(x, z); - /* sinl(Inf or NaN) is NaN, sinl(0) is 0 */ - else if ((x + x == x && x != 0.0) || x != x) - return x-x; /* NaN */ + /* cosl(Inf) is NaN, cosl(0) is 1 */ + else if (x + x == x && x != 0.0) + return x - x; /* NaN */ - /* argument reduction needed */ - else { - n = ieee754_rem_pio2l(x,y); - switch(n&3) { - case 0: return kernel_cosl(y[0],y[1]); - case 1: return -kernel_sinl(y[0],y[1],1); - case 2: return -kernel_cosl(y[0],y[1]); - default: - return kernel_sinl(y[0],y[1],1); - } - } + /* argument reduction needed */ + else + { + n = ieee754_rem_pio2l (x, y); + switch (n & 3) + { + case 0: + return kernel_cosl (y[0], y[1]); + case 1: + return -kernel_sinl (y[0], y[1], 1); + case 2: + return -kernel_cosl (y[0], y[1]); + default: + return kernel_sinl (y[0], y[1], 1); + } + } } #if 0 int main (void) { - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492)); - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492 *29)); - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492 *2)); - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492 *30)); - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492 *4)); - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492 *32)); - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492 *2/3)); - printf ("%.16Lg\n", cosl(0.7853981633974483096156608458198757210492 *4/3)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492 *29)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492 *2)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492 *30)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492 *4)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492 *32)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492 *2/3)); + printf ("%.16Lg\n", cosl (0.7853981633974483096156608458198757210492 *4/3)); } #endif