103 lines
1.9 KiB
C
103 lines
1.9 KiB
C
/*
|
|
* (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
|
|
*
|
|
* This product is part of the Amsterdam Compiler Kit.
|
|
*
|
|
* Permission to use, sell, duplicate or disclose this software must be
|
|
* obtained in writing. Requests for such permissions may be sent to
|
|
*
|
|
* Dr. Andrew S. Tanenbaum
|
|
* Wiskundig Seminarium
|
|
* Vrije Universiteit
|
|
* Postbox 7161
|
|
* 1007 MC Amsterdam
|
|
* The Netherlands
|
|
*
|
|
*/
|
|
|
|
/* $Header $ */
|
|
|
|
/* Author: J.W. Stevenson */
|
|
|
|
extern double _fif();
|
|
|
|
/*
|
|
C program for floating point sin/cos.
|
|
Calls _fif.
|
|
There are no error exits.
|
|
Coefficients are #3370 from Hart & Cheney (18.80D).
|
|
*/
|
|
|
|
static double twoopi = 0.63661977236758134308;
|
|
static double p0 = .1357884097877375669092680e8;
|
|
static double p1 = -.4942908100902844161158627e7;
|
|
static double p2 = .4401030535375266501944918e6;
|
|
static double p3 = -.1384727249982452873054457e5;
|
|
static double p4 = .1459688406665768722226959e3;
|
|
static double q0 = .8644558652922534429915149e7;
|
|
static double q1 = .4081792252343299749395779e6;
|
|
static double q2 = .9463096101538208180571257e4;
|
|
static double q3 = .1326534908786136358911494e3;
|
|
|
|
static double
|
|
sinus(arg, quad)
|
|
double arg;
|
|
int quad;
|
|
{
|
|
double e, f;
|
|
double ysq;
|
|
double x,y;
|
|
int k;
|
|
double temp1, temp2;
|
|
|
|
x = arg;
|
|
if(x<0) {
|
|
x = -x;
|
|
quad = quad + 2;
|
|
}
|
|
x = x*twoopi; /*underflow?*/
|
|
if(x>32764){
|
|
y = _fif(x, 10.0, &e);
|
|
e = e + quad;
|
|
_fif(0.25, e, &f);
|
|
quad = e - 4*f;
|
|
}else{
|
|
k = x;
|
|
y = x - k;
|
|
quad = (quad + k) & 03;
|
|
}
|
|
if (quad & 01)
|
|
y = 1-y;
|
|
if(quad > 1)
|
|
y = -y;
|
|
|
|
ysq = y*y;
|
|
temp1 = ((((p4*ysq+p3)*ysq+p2)*ysq+p1)*ysq+p0)*y;
|
|
temp2 = ((((ysq+q3)*ysq+q2)*ysq+q1)*ysq+q0);
|
|
return(temp1/temp2);
|
|
}
|
|
|
|
double
|
|
_cos(arg)
|
|
double arg;
|
|
{
|
|
if(arg<0)
|
|
arg = -arg;
|
|
return(sinus(arg, 1));
|
|
}
|
|
|
|
double
|
|
_sin(arg)
|
|
double arg;
|
|
{
|
|
return(sinus(arg, 0));
|
|
}
|
|
|
|
/* EXTENSION */
|
|
double
|
|
_tan(arg)
|
|
double arg;
|
|
{
|
|
return( _sin(arg)/_cos(arg));
|
|
}
|