X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmath%2Fatanl.c;h=33ecff0de8d80ded1ec22c735c4e53d273fe3849;hb=3bb6bd85808ace7b588d1c523bb7badfd9e72650;hp=4e99955ed8200ba2e80ce217d1c31adc25d91db9;hpb=b69f695acedd4ce2798ef9ea28d834ceccc789bd;p=musl diff --git a/src/math/atanl.c b/src/math/atanl.c index 4e99955e..33ecff0d 100644 --- a/src/math/atanl.c +++ b/src/math/atanl.c @@ -23,9 +23,52 @@ long double atanl(long double x) } #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 #include "__invtrigl.h" -static const long double -one = 1.0, -huge = 1.0e300; + +#define ATAN_CONST (BIAS + 65) /* 2**65 */ +#define ATAN_LINEAR (BIAS - 32) /* 2**-32 */ +static const long double huge = 1.0e300; + +static const long double atanhi[] = { + 4.63647609000806116202e-01L, + 7.85398163397448309628e-01L, + 9.82793723247329067960e-01L, + 1.57079632679489661926e+00L, +}; + +static const long double atanlo[] = { + 1.18469937025062860669e-20L, + -1.25413940316708300586e-20L, + 2.55232234165405176172e-20L, + -2.50827880633416601173e-20L, +}; + +static const long double aT[] = { + 3.33333333333333333017e-01L, + -1.99999999999999632011e-01L, + 1.42857142857046531280e-01L, + -1.11111111100562372733e-01L, + 9.09090902935647302252e-02L, + -7.69230552476207730353e-02L, + 6.66661718042406260546e-02L, + -5.88158892835030888692e-02L, + 5.25499891539726639379e-02L, + -4.70119845393155721494e-02L, + 4.03539201366454414072e-02L, + -2.91303858419364158725e-02L, + 1.24822046299269234080e-02L, +}; + +static long double T_even(long double x) +{ + return aT[0] + x * (aT[2] + x * (aT[4] + x * (aT[6] + + x * (aT[8] + x * (aT[10] + x * aT[12]))))); +} + +static long double T_odd(long double x) +{ + return aT[1] + x * (aT[3] + x * (aT[5] + x * (aT[7] + + x * (aT[9] + x * aT[11])))); +} long double atanl(long double x) { @@ -53,7 +96,7 @@ long double atanl(long double x) if (expman < ((BIAS - 2) << 8) + 0xc0) { /* |x| < 0.4375 */ if (expt < ATAN_LINEAR) { /* if |x| is small, atanl(x)~=x */ /* raise inexact */ - if (huge+x > one) + if (huge+x > 1.0) return x; } id = -1; @@ -62,15 +105,15 @@ long double atanl(long double x) if (expman < (BIAS << 8) + 0x30) { /* |x| < 1.1875 */ if (expman < ((BIAS - 1) << 8) + 0x60) { /* 7/16 <= |x| < 11/16 */ id = 0; - x = (2.0*x-one)/(2.0+x); + x = (2.0*x-1.0)/(2.0+x); } else { /* 11/16 <= |x| < 19/16 */ id = 1; - x = (x-one)/(x+one); + x = (x-1.0)/(x+1.0); } } else { if (expman < ((BIAS + 1) << 8) + 0x38) { /* |x| < 2.4375 */ id = 2; - x = (x-1.5)/(one+1.5*x); + x = (x-1.5)/(1.0+1.5*x); } else { /* 2.4375 <= |x| < 2^ATAN_CONST */ id = 3; x = -1.0/x;