X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fmath%2Fatanl.c;h=e76693e47d339baf503a08832898ff9f34d431d9;hp=36072c173b02e9618f5253f50dbdca665fe7dd82;hb=01739902843e93ec6e9bf8e17d32c8ddf73fad81;hpb=0cbb65479147ecdaa664e88cc2a5a925f3de502f diff --git a/src/math/atanl.c b/src/math/atanl.c index 36072c17..e76693e4 100644 --- a/src/math/atanl.c +++ b/src/math/atanl.c @@ -22,8 +22,48 @@ long double atanl(long double x) return atan(x); } #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 -#include "__invtrigl.h" -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) { @@ -36,29 +76,27 @@ long double atanl(long double x) u.e = x; expsign = u.xbits.expsign; expt = expsign & 0x7fff; - if (expt >= ATAN_CONST) { /* if |x| is large, atan(x)~=pi/2 */ - if (expt == BIAS + LDBL_MAX_EXP && + if (expt >= 0x3fff + 65) { /* if |x| is large, atan(x)~=pi/2 */ + if (expt == 0x7fff && ((u.bits.manh&~LDBL_NBIT)|u.bits.manl)!=0) /* NaN */ return x+x; - if (expsign > 0) - return atanhi[3]+atanlo[3]; - else - return -atanhi[3]-atanlo[3]; + z = atanhi[3] + 0x1p-120f; + return expsign < 0 ? -z : z; } /* Extract the exponent and the first few bits of the mantissa. */ /* XXX There should be a more convenient way to do this. */ - expman = (expt << 8) | ((u.bits.manh >> (MANH_SIZE - 9)) & 0xff); - 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 > 1.0) - return x; + expman = (expt << 8) | ((u.bits.manh >> (LDBL_MANH_SIZE - 9)) & 0xff); + if (expman < ((0x3fff - 2) << 8) + 0xc0) { /* |x| < 0.4375 */ + if (expt < 0x3fff - 32) { /* if |x| is small, atanl(x)~=x */ + /* raise inexact if x!=0 */ + FORCE_EVAL(x + 0x1p120f); + return x; } id = -1; } else { x = fabsl(x); - if (expman < (BIAS << 8) + 0x30) { /* |x| < 1.1875 */ - if (expman < ((BIAS - 1) << 8) + 0x60) { /* 7/16 <= |x| < 11/16 */ + if (expman < (0x3fff << 8) + 0x30) { /* |x| < 1.1875 */ + if (expman < ((0x3fff - 1) << 8) + 0x60) { /* 7/16 <= |x| < 11/16 */ id = 0; x = (2.0*x-1.0)/(2.0+x); } else { /* 11/16 <= |x| < 19/16 */ @@ -66,7 +104,7 @@ long double atanl(long double x) x = (x-1.0)/(x+1.0); } } else { - if (expman < ((BIAS + 1) << 8) + 0x38) { /* |x| < 2.4375 */ + if (expman < ((0x3fff + 1) << 8) + 0x38) { /* |x| < 2.4375 */ id = 2; x = (x-1.5)/(1.0+1.5*x); } else { /* 2.4375 <= |x| < 2^ATAN_CONST */