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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"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double atan2l(long double y, long double x)
{
return atan2(y, x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
#include "__invtrigl.h"
long double atan2l(long double y, long double x)
{
union IEEEl2bits ux, uy;
long double z;
int m;
uint16_t exptx, expsignx, expty, expsigny;
if (isnan(x) || isnan(y))
return x+y;
if (x == 1)
return atanl(y);
uy.e = y;
expsigny = uy.xbits.expsign;
expty = expsigny & 0x7fff;
ux.e = x;
expsignx = ux.xbits.expsign;
exptx = expsignx & 0x7fff;
m = ((expsigny>>15)&1) | ((expsignx>>14)&2); /* 2*sign(x)+sign(y) */
if (y == 0) {
switch(m) {
case 0:
case 1: return y; /* atan(+-0,+anything)=+-0 */
case 2: return 2*pio2_hi+0x1p-120f; /* atan(+0,-anything) = pi */
case 3: return -2*pio2_hi-0x1p-120f; /* atan(-0,-anything) =-pi */
}
}
if (x == 0)
return m&1 ? -pio2_hi-0x1p-120f : pio2_hi+0x1p-120f;
/* when x is INF */
if (exptx == 0x7fff) {
if (expty == 0x7fff) {
switch(m) {
case 0: return pio2_hi*0.5+0x1p-120f; /* atan(+INF,+INF) */
case 1: return -pio2_hi*0.5-0x1p-120f; /* atan(-INF,+INF) */
case 2: return 1.5*pio2_hi+0x1p-120f; /* atan(+INF,-INF) */
case 3: return -1.5*pio2_hi-0x1p-120f; /* 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+0x1p-120f; /* atan(+...,-INF) */
case 3: return -2*pio2_hi-0x1p-120f; /* atan(-...,-INF) */
}
}
}
/* when y is INF */
if (exptx+120 < expty || expty == 0x7fff)
return m&1 ? -pio2_hi-0x1p-120f : pio2_hi+0x1p-120f;
if ((m&2) && expty+120 < exptx) /* |y/x| tiny, 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
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