/*
* tan(x) = sin(x) / cos(x)
*/
struct fpn *
fpu_tan(struct fpemu *fe)
{
struct fpn x;
struct fpn s;
struct fpn *r;
if (ISNAN(&fe->fe_f2))
return &fe->fe_f2;
if (ISINF(&fe->fe_f2))
return fpu_newnan(fe);
/* if x is +0/-0, return +0/-0 */
if (ISZERO(&fe->fe_f2))
return &fe->fe_f2;
CPYFPN(&x, &fe->fe_f2);
/* sin(x) */
CPYFPN(&fe->fe_f2, &x);
r = fpu_sin(fe);
CPYFPN(&s, r);
/* cos(x) */
CPYFPN(&fe->fe_f2, &x);
r = fpu_cos(fe);
CPYFPN(&fe->fe_f2, r);
CPYFPN(&fe->fe_f1, &s);
r = fpu_div(fe);
return r;
}
/* undefined functions will result in a berp (panic) or whatever when called */
double sin( double ang )
{
extern double fpu_sin(double);
return fpu_sin(ang);
}