| /* 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 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 |
