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| | /* origin: FreeBSD /usr/src/lib/msun/src/e_atan2l.c */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunSoft, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*
*/
/*
* See comments in atan2.c.
* Converted to long double by David Schultz <das@FreeBSD.ORG>.
*/
#include "libm.h"
#ifdef LONG_DOUBLE_IS_BINARY64
long double atan2l(long double y, long double x)
{
return atan2(y, x);
}
#elif defined(LONG_DOUBLE_IS_X87_EXTENDED) || defined(LONG_DOUBLE_IS_BINARY128)
#include "__invtrigl.h"
long double atan2l(long double y, long double x)
{
union ldshape ux, uy;
long double z;
int m, ex, ey;
if (isnan(x) || isnan(y))
return x+y;
if (x == 1)
return atanl(y);
ux.f = x;
uy.f = y;
ex = ux.i.se & 0x7fff;
ey = uy.i.se & 0x7fff;
m = 2*(ux.i.se>>15) | uy.i.se>>15;
if (y == 0) {
switch(m) {
case 0:
case 1: return y; /* atan(+-0,+anything)=+-0 */
case 2: return 2*pio2_hi; /* atan(+0,-anything) = pi */
case 3: return -2*pio2_hi; /* atan(-0,-anything) =-pi */
}
}
if (x == 0)
return m&1 ? -pio2_hi : pio2_hi;
if (ex == 0x7fff) {
if (ey == 0x7fff) {
switch(m) {
case 0: return pio2_hi/2; /* atan(+INF,+INF) */
case 1: return -pio2_hi/2; /* atan(-INF,+INF) */
case 2: return 1.5*pio2_hi; /* atan(+INF,-INF) */
case 3: return -1.5*pio2_hi; /* atan(-INF,-INF) */
}
} else {
switch(m) {
case 0: return 0.0; /* atan(+...,+INF) */
case 1: return -0.0; /* atan(-...,+INF) */
case 2: return 2*pio2_hi; /* atan(+...,-INF) */
case 3: return -2*pio2_hi; /* atan(-...,-INF) */
}
}
}
if (ex+120 < ey || ey == 0x7fff)
return m&1 ? -pio2_hi : pio2_hi;
/* z = atan(|y/x|) without spurious underflow */
if ((m&2) && ey+120 < ex) /* |y/x| < 0x1p-120, x<0 */
z = 0.0;
else
z = atanl(fabsl(y/x));
switch (m) {
case 0: return z; /* atan(+,+) */
case 1: return -z; /* atan(-,+) */
case 2: return 2*pio2_hi-(z-2*pio2_lo); /* atan(+,-) */
default: /* case 3 */
return (z-2*pio2_lo)-2*pio2_hi; /* atan(-,-) */
}
}
#endif
|