X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fsinl.c;h=b0106b4fa4e706d20398bf6bf47f52e91f8caf1a;hb=ea6b0b0c5caf18a059bb974a2d0c1739d5be671c;hp=3bec0bb4aaaa2c3d546050636b945a7264556fbb;hpb=5657b2536d242966c41c268b9ab4fe8df727bb13;p=gnulib.git diff --git a/lib/sinl.c b/lib/sinl.c index 3bec0bb4a..b0106b4fa 100644 --- a/lib/sinl.c +++ b/lib/sinl.c @@ -13,26 +13,31 @@ * ==================================================== */ +#include + +/* Specification. */ +#include + /* sinl(x) * 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: @@ -41,16 +46,10 @@ * trig(NaN) is that NaN; * * Accuracy: - * TRIG(x) returns trig(x) nearly rounded + * TRIG(x) returns trig(x) nearly rounded */ -#include - -#include "mathl.h" - #include "trigl.h" -#include "trigl.c" -#include "sincosl.c" long double sinl (long double x) @@ -58,44 +57,48 @@ sinl (long double x) long double y[2], z = 0.0L; int n; + /* sinl(NaN) is NaN */ + if (isnanl (x)) + return x; + /* |x| ~< pi/4 */ - if (x >= -0.7853981633974483096156608458198757210492 && - x <= 0.7853981633974483096156608458198757210492) + if (x >= -0.7853981633974483096156608458198757210492 + && x <= 0.7853981633974483096156608458198757210492) return kernel_sinl (x, z, 0); - /* sinl(Inf or NaN) is NaN, sinl(0) is 0 */ - else if (x + x == x || x != x) - return x - x; /* NaN */ + /* sinl(Inf) is NaN, sinl(0) is 0 */ + else if (x + x == x) + return x - x; /* NaN */ /* argument reduction needed */ else { n = ieee754_rem_pio2l (x, y); switch (n & 3) - { - case 0: - return kernel_sinl (y[0], y[1], 1); - case 1: - return kernel_cosl (y[0], y[1]); - case 2: - return -kernel_sinl (y[0], y[1], 1); - default: - return -kernel_cosl (y[0], y[1]); - } + { + case 0: + return kernel_sinl (y[0], y[1], 1); + case 1: + return kernel_cosl (y[0], y[1]); + case 2: + return -kernel_sinl (y[0], y[1], 1); + default: + return -kernel_cosl (y[0], y[1]); + } } } #if 0 int -main () +main (void) { - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492)); - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492 *29)); - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492 *2)); - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492 *30)); - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492 *4)); - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492 *32)); - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492 *2/3)); - printf ("%.16Lg\n", sinl(0.7853981633974483096156608458198757210492 *4/3)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *29)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *2)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *30)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *4)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *32)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *2/3)); + printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *4/3)); } #endif