diff options
Diffstat (limited to 'sysdeps/libm-ieee754/e_atan2l.c')
| -rw-r--r-- | sysdeps/libm-ieee754/e_atan2l.c | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_atan2l.c b/sysdeps/libm-ieee754/e_atan2l.c new file mode 100644 index 0000000000..6b76f96533 --- /dev/null +++ b/sysdeps/libm-ieee754/e_atan2l.c @@ -0,0 +1,136 @@ +/* e_atan2l.c -- long double version of e_atan2.c. + * Conversion to long double by Ulrich Drepper, + * Cygnus Support, drepper@cygnus.com. + */ + +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunPro, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +#if defined(LIBM_SCCS) && !defined(lint) +static char rcsid[] = "$NetBSD: $"; +#endif + +/* __ieee754_atan2l(y,x) + * Method : + * 1. Reduce y to positive by atan2(y,x)=-atan2(-y,x). + * 2. Reduce x to positive by (if x and y are unexceptional): + * ARG (x+iy) = arctan(y/x) ... if x > 0, + * ARG (x+iy) = pi - arctan[y/(-x)] ... if x < 0, + * + * Special cases: + * + * ATAN2((anything), NaN ) is NaN; + * ATAN2(NAN , (anything) ) is NaN; + * ATAN2(+-0, +(anything but NaN)) is +-0 ; + * ATAN2(+-0, -(anything but NaN)) is +-pi ; + * ATAN2(+-(anything but 0 and NaN), 0) is +-pi/2; + * ATAN2(+-(anything but INF and NaN), +INF) is +-0 ; + * ATAN2(+-(anything but INF and NaN), -INF) is +-pi; + * ATAN2(+-INF,+INF ) is +-pi/4 ; + * ATAN2(+-INF,-INF ) is +-3pi/4; + * ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-pi/2; + * + * Constants: + * The hexadecimal values are the intended ones for the following + * constants. The decimal values may be used, provided that the + * compiler will convert from decimal to binary accurately enough + * to produce the hexadecimal values shown. + */ + +#include "math.h" +#include "math_private.h" + +#ifdef __STDC__ +static const long double +#else +static long double +#endif +tiny = 1.0e-4900L, +zero = 0.0, +pi_o_4 = 7.85398163397448309628202E-01L, /* 0x3FFE, 0xC90FDAA2, 0x2168C235 */ +pi_o_2 = 1.5707963267948966192564E+00L, /* 0x3FFF, 0xC90FDAA2, 0x2168C235 */ +pi = 3.14159265358979323851281E+00L, /* 0x4000, 0xC90FDAA2, 0x2168C235 */ +pi_lo = -5.01655761266833202345176e-20L;/* 0xBFBE, 0xECE675D1, 0xFC8F8CBB */ + +#ifdef __STDC__ + long double __ieee754_atan2l(long double y, long double x) +#else + long double __ieee754_atan2l(y,x) + long double y,x; +#endif +{ + long double z; + int32_t k,m,hx,hy,ix,iy; + u_int32_t sx,sy,lx,ly; + + EXTRACT_LDOUBLE_WORDS(sx,hx,lx,x); + ix = sx&0x7fff; + lx |= hx ^ 0x80000000; + EXTRACT_LDOUBLE_WORDS(sy,hy,ly,y); + iy = sy&0x7fff; + ly |= hy ^ 0x80000000; + if(((2*ix|((lx|-lx)>>31))>0xfffe)|| + ((2*iy|((ly|-ly)>>31))>0xfffe)) /* x or y is NaN */ + return x+y; + if((sx-0x3fff|lx)==0) return __atanl(y); /* x=1.0 */ + m = ((sy>>15)&1)|((sx>>14)&2); /* 2*sign(x)+sign(y) */ + + /* when y = 0 */ + if((iy|ly)==0) { + switch(m) { + case 0: + case 1: return y; /* atan(+-0,+anything)=+-0 */ + case 2: return pi+tiny;/* atan(+0,-anything) = pi */ + case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */ + } + } + /* when x = 0 */ + if((ix|lx)==0) return (sy>=0x8000)? -pi_o_2-tiny: pi_o_2+tiny; + + /* when x is INF */ + if(ix==0x7fff) { + if(iy==0x7fff) { + switch(m) { + case 0: return pi_o_4+tiny;/* atan(+INF,+INF) */ + case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */ + case 2: return 3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/ + case 3: return -3.0*pi_o_4-tiny;/*atan(-INF,-INF)*/ + } + } else { + switch(m) { + case 0: return zero ; /* atan(+...,+INF) */ + case 1: return -zero ; /* atan(-...,+INF) */ + case 2: return pi+tiny ; /* atan(+...,-INF) */ + case 3: return -pi-tiny ; /* atan(-...,-INF) */ + } + } + } + /* when y is INF */ + if(iy==0x7fff) return (hy>=0x8000)? -pi_o_2-tiny: pi_o_2+tiny; + + /* compute y/x */ + k = sy-sx; + if(k > 70) z=pi_o_2+0.5*pi_lo; /* |y/x| > 2**70 */ + else if(sx>=0x8000&&k<-70) z=0.0; /* |y|/x < -2**70 */ + else z=__atanl(fabsl(y/x)); /* safe to do y/x */ + switch (m) { + case 0: return z ; /* atan(+,+) */ + case 1: { + u_int32_t sz; + GET_LDOUBLE_EXP(sz,z); + SET_LDOUBLE_EXP(z,sy ^ 0x8000); + } + return z ; /* atan(-,+) */ + case 2: return pi-(z-pi_lo);/* atan(+,-) */ + default: /* case 3 */ + return (z-pi_lo)-pi;/* atan(-,-) */ + } +} |