diff options
Diffstat (limited to 'newlib/libm/ld/e_atan2l.c')
| -rw-r--r-- | newlib/libm/ld/e_atan2l.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/newlib/libm/ld/e_atan2l.c b/newlib/libm/ld/e_atan2l.c new file mode 100644 index 000000000..619bfb595 --- /dev/null +++ b/newlib/libm/ld/e_atan2l.c @@ -0,0 +1,120 @@ + +/* @(#)e_atan2.c 1.3 95/01/18 */ +/* FreeBSD: head/lib/msun/src/e_atan2.c 176451 2008-02-22 02:30:36Z das */ +/* + * ==================================================== + * 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. + * ==================================================== + * + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * See comments in e_atan2.c. + * Converted to long double by David Schultz <das@FreeBSD.ORG>. + */ + +#include <float.h> + +#include "invtrig.h" +#include "math.h" +#include "math_private.h" + +static volatile long double +tiny = 1.0e-300; +static const long double +zero = 0.0; + +#ifdef __i386__ +/* XXX Work around the fact that gcc truncates long double constants on i386 */ +static volatile double +pi1 = 3.14159265358979311600e+00, /* 0x1.921fb54442d18p+1 */ +pi2 = 1.22514845490862001043e-16; /* 0x1.1a80000000000p-53 */ +#define pi ((long double)pi1 + pi2) +#else +static const long double +pi = 3.14159265358979323846264338327950280e+00L; +#endif + +long double +atan2l(long double y, long double x) +{ + union IEEEl2bits ux, uy; + long double z; + int32_t k,m; + int16_t exptx, expsignx, expty, expsigny; + + uy.e = y; + expsigny = uy.xbits.expsign; + expty = expsigny & 0x7fff; + ux.e = x; + expsignx = ux.xbits.expsign; + exptx = expsignx & 0x7fff; + + if ((exptx==BIAS+LDBL_MAX_EXP && + ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl)!=0) || /* x is NaN */ + (expty==BIAS+LDBL_MAX_EXP && + ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl)!=0)) /* y is NaN */ + return nan_mix(x, y); + if (expsignx==BIAS && ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl)==0) + return atanl(y); /* x=1.0 */ + m = ((expsigny>>15)&1)|((expsignx>>14)&2); /* 2*sign(x)+sign(y) */ + + /* when y = 0 */ + if(expty==0 && ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl)==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(exptx==0 && ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl)==0) + return (expsigny<0)? -pio2_hi-tiny: pio2_hi+tiny; + + /* when x is INF */ + if(exptx==BIAS+LDBL_MAX_EXP) { + if(expty==BIAS+LDBL_MAX_EXP) { + switch(m) { + case 0: return pio2_hi*0.5+tiny;/* atan(+INF,+INF) */ + case 1: return -pio2_hi*0.5-tiny;/* atan(-INF,+INF) */ + case 2: return 1.5*pio2_hi+tiny;/*atan(+INF,-INF)*/ + case 3: return -1.5*pio2_hi-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(expty==BIAS+LDBL_MAX_EXP) + return (expsigny<0)? -pio2_hi-tiny: pio2_hi+tiny; + + /* compute y/x */ + k = expty-exptx; + if(k > LDBL_MANT_DIG+2) { /* |y/x| huge */ + z=pio2_hi+pio2_lo; + m&=1; + } + else if(expsignx<0&&k<-LDBL_MANT_DIG-2) z=0.0; /* |y/x| tiny, x<0 */ + else z=atanl(fabsl(y/x)); /* safe to do y/x */ + switch (m) { + case 0: return z ; /* atan(+,+) */ + case 1: return -z ; /* atan(-,+) */ + case 2: return pi-(z-pi_lo);/* atan(+,-) */ + default: /* case 3 */ + return (z-pi_lo)-pi;/* atan(-,-) */ + } +} |