asin.rar_ARGUMENT!_cody and waite

#if !defined(lint) && defined(SCCSIDS) static char sccsid[] = "@(#)asin.c 1.1 92/07/30 SMI"; /* from S5R3 1.14 */ #endif /* Copyright (c) 1984 AT&T */ /* All Rights Reserved */ /* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T */ /* The copyright notice above does not evidence any */ /* actual or intended publication of such source code. */ /*LINTLIBRARY*/ /* * C program for double-precision asin/acos. * Returns EDOM error and value 0 if |argument| > 1. * Algorithm and coefficients from Cody and Waite (1980). * Calls sqrt if |argument| > 0.5. */ #include <math.h> #include <values.h> #include <errno.h> double asin(x) double x; { extern double asin_acos(); return (asin_acos(x, 0)); } static double asin_acos(x, acosflag) register double x; int acosflag; { register double y; register int neg = 0, large = 0; struct exception exc; exc.arg1 = x; if (x < 0) { x = -x; neg++; } if (x > 1) { exc.type = DOMAIN; exc.name = acosflag ? "acos" : "asin"; exc.retval = 0.0; if (!matherr(&exc)) { (void) write(2, exc.name, 4); (void) write(2, ": DOMAIN error\n", 15); errno = EDOM; } return (exc.retval); } if (x > X_EPS) { /* skip for efficiency and to prevent underflow */ static double p[] = { -0.69674573447350646411e0, 0.10152522233806463645e2, -0.39688862997504877339e2, 0.57208227877891731407e2, -0.27368494524164255994e2, }, q[] = { 1.0, -0.23823859153670238830e2, 0.15095270841030604719e3, -0.38186303361750149284e3, 0.41714430248260412556e3, -0.16421096714498560795e3, }; if (x <= 0.5) y = x * x; else { large++; y = 0.5 - 0.5 * x; x = -sqrt(y); x += x; } x += x * y * _POLY4(y, p)/_POLY5(y, q); } if (acosflag) { if (!neg) x = -x; return (!large ? M_PI_2 + x : neg ? M_PI + x : x); } if (large) x += M_PI_2; return (neg ? -x : x); } double acos(x) double x; { return (asin_acos(x, 1)); }