From 885f5974cdf65b59415837ae97f5a14ef1350670 Mon Sep 17 00:00:00 2001 From: Kacper Date: Tue, 9 Dec 2025 19:20:15 +0100 Subject: feat: add gzip and new headers --- lib/libm/erff.c | 201 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 201 insertions(+) create mode 100644 lib/libm/erff.c (limited to 'lib/libm/erff.c') diff --git a/lib/libm/erff.c b/lib/libm/erff.c new file mode 100644 index 00000000..26170f62 --- /dev/null +++ b/lib/libm/erff.c @@ -0,0 +1,201 @@ +/* origin: FreeBSD /usr/src/lib/msun/src/s_erff.c */ +/* + * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@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. + * ==================================================== + */ + +#include "libm.h" + +static const float erx = 8.4506291151e-01, /* 0x3f58560b */ + /* + * Coefficients for approximation to erf on [0,0.84375] + */ + efx8 = 1.0270333290e+00, /* 0x3f8375d4 */ + pp0 = 1.2837916613e-01, /* 0x3e0375d4 */ + pp1 = -3.2504209876e-01, /* 0xbea66beb */ + pp2 = -2.8481749818e-02, /* 0xbce9528f */ + pp3 = -5.7702702470e-03, /* 0xbbbd1489 */ + pp4 = -2.3763017452e-05, /* 0xb7c756b1 */ + qq1 = 3.9791721106e-01, /* 0x3ecbbbce */ + qq2 = 6.5022252500e-02, /* 0x3d852a63 */ + qq3 = 5.0813062117e-03, /* 0x3ba68116 */ + qq4 = 1.3249473704e-04, /* 0x390aee49 */ + qq5 = -3.9602282413e-06, /* 0xb684e21a */ + /* + * Coefficients for approximation to erf in [0.84375,1.25] + */ + pa0 = -2.3621185683e-03, /* 0xbb1acdc6 */ + pa1 = 4.1485610604e-01, /* 0x3ed46805 */ + pa2 = -3.7220788002e-01, /* 0xbebe9208 */ + pa3 = 3.1834661961e-01, /* 0x3ea2fe54 */ + pa4 = -1.1089469492e-01, /* 0xbde31cc2 */ + pa5 = 3.5478305072e-02, /* 0x3d1151b3 */ + pa6 = -2.1663755178e-03, /* 0xbb0df9c0 */ + qa1 = 1.0642088205e-01, /* 0x3dd9f331 */ + qa2 = 5.4039794207e-01, /* 0x3f0a5785 */ + qa3 = 7.1828655899e-02, /* 0x3d931ae7 */ + qa4 = 1.2617121637e-01, /* 0x3e013307 */ + qa5 = 1.3637083583e-02, /* 0x3c5f6e13 */ + qa6 = 1.1984500103e-02, /* 0x3c445aa3 */ + /* + * Coefficients for approximation to erfc in [1.25,1/0.35] + */ + ra0 = -9.8649440333e-03, /* 0xbc21a093 */ + ra1 = -6.9385856390e-01, /* 0xbf31a0b7 */ + ra2 = -1.0558626175e+01, /* 0xc128f022 */ + ra3 = -6.2375331879e+01, /* 0xc2798057 */ + ra4 = -1.6239666748e+02, /* 0xc322658c */ + ra5 = -1.8460508728e+02, /* 0xc3389ae7 */ + ra6 = -8.1287437439e+01, /* 0xc2a2932b */ + ra7 = -9.8143291473e+00, /* 0xc11d077e */ + sa1 = 1.9651271820e+01, /* 0x419d35ce */ + sa2 = 1.3765776062e+02, /* 0x4309a863 */ + sa3 = 4.3456588745e+02, /* 0x43d9486f */ + sa4 = 6.4538726807e+02, /* 0x442158c9 */ + sa5 = 4.2900814819e+02, /* 0x43d6810b */ + sa6 = 1.0863500214e+02, /* 0x42d9451f */ + sa7 = 6.5702495575e+00, /* 0x40d23f7c */ + sa8 = -6.0424413532e-02, /* 0xbd777f97 */ + /* + * Coefficients for approximation to erfc in [1/.35,28] + */ + rb0 = -9.8649431020e-03, /* 0xbc21a092 */ + rb1 = -7.9928326607e-01, /* 0xbf4c9dd4 */ + rb2 = -1.7757955551e+01, /* 0xc18e104b */ + rb3 = -1.6063638306e+02, /* 0xc320a2ea */ + rb4 = -6.3756646729e+02, /* 0xc41f6441 */ + rb5 = -1.0250950928e+03, /* 0xc480230b */ + rb6 = -4.8351919556e+02, /* 0xc3f1c275 */ + sb1 = 3.0338060379e+01, /* 0x41f2b459 */ + sb2 = 3.2579251099e+02, /* 0x43a2e571 */ + sb3 = 1.5367296143e+03, /* 0x44c01759 */ + sb4 = 3.1998581543e+03, /* 0x4547fdbb */ + sb5 = 2.5530502930e+03, /* 0x451f90ce */ + sb6 = 4.7452853394e+02, /* 0x43ed43a7 */ + sb7 = -2.2440952301e+01; /* 0xc1b38712 */ + +static float erfc1(float x) +{ + float_t s, P, Q; + + s = fabsf(x) - 1; + P = pa0 + + s * (pa1 + s * (pa2 + s * (pa3 + s * (pa4 + s * (pa5 + s * pa6))))); + Q = 1 + + s * (qa1 + s * (qa2 + s * (qa3 + s * (qa4 + s * (qa5 + s * qa6))))); + return 1 - erx - P / Q; +} + +static float erfc2(uint32_t ix, float x) +{ + float_t s, R, S; + float z; + + if (ix < 0x3fa00000) /* |x| < 1.25 */ + return erfc1(x); + + x = fabsf(x); + s = 1 / (x * x); + if (ix < 0x4036db6d) { /* |x| < 1/0.35 */ + R = ra0 + + s * (ra1 + + s * (ra2 + + s * (ra3 + + s * (ra4 + + s * (ra5 + s * (ra6 + s * ra7)))))); + S = 1.0f + + s * (sa1 + + s * (sa2 + + s * (sa3 + + s * (sa4 + + s * (sa5 + + s * (sa6 + + s * (sa7 + s * sa8))))))); + } else { /* |x| >= 1/0.35 */ + R = rb0 + + s * (rb1 + + s * (rb2 + + s * (rb3 + s * (rb4 + s * (rb5 + s * rb6))))); + S = 1.0f + + s * (sb1 + + s * (sb2 + + s * (sb3 + + s * (sb4 + + s * (sb5 + s * (sb6 + s * sb7)))))); + } + GET_FLOAT_WORD(ix, x); + SET_FLOAT_WORD(z, ix & 0xffffe000); + return expf(-z * z - 0.5625f) * expf((z - x) * (z + x) + R / S) / x; +} + +float erff(float x) +{ + float r, s, z, y; + uint32_t ix; + int sign; + + GET_FLOAT_WORD(ix, x); + sign = ix >> 31; + ix &= 0x7fffffff; + if (ix >= 0x7f800000) { + /* erf(nan)=nan, erf(+-inf)=+-1 */ + return 1 - 2 * sign + 1 / x; + } + if (ix < 0x3f580000) { /* |x| < 0.84375 */ + if (ix < 0x31800000) { /* |x| < 2**-28 */ + /*avoid underflow */ + return 0.125f * (8 * x + efx8 * x); + } + z = x * x; + r = pp0 + z * (pp1 + z * (pp2 + z * (pp3 + z * pp4))); + s = 1 + z * (qq1 + z * (qq2 + z * (qq3 + z * (qq4 + z * qq5)))); + y = r / s; + return x + x * y; + } + if (ix < 0x40c00000) /* |x| < 6 */ + y = 1 - erfc2(ix, x); + else + y = 1 - 0x1p-120f; + return sign ? -y : y; +} + +float erfcf(float x) +{ + float r, s, z, y; + uint32_t ix; + int sign; + + GET_FLOAT_WORD(ix, x); + sign = ix >> 31; + ix &= 0x7fffffff; + if (ix >= 0x7f800000) { + /* erfc(nan)=nan, erfc(+-inf)=0,2 */ + return 2 * sign + 1 / x; + } + + if (ix < 0x3f580000) { /* |x| < 0.84375 */ + if (ix < 0x23800000) /* |x| < 2**-56 */ + return 1.0f - x; + z = x * x; + r = pp0 + z * (pp1 + z * (pp2 + z * (pp3 + z * pp4))); + s = 1.0f + + z * (qq1 + z * (qq2 + z * (qq3 + z * (qq4 + z * qq5)))); + y = r / s; + if (sign || ix < 0x3e800000) /* x < 1/4 */ + return 1.0f - (x + x * y); + return 0.5f - (x - 0.5f + x * y); + } + if (ix < 0x41e00000) { /* |x| < 28 */ + return sign ? 2 - erfc2(ix, x) : erfc2(ix, x); + } + return sign ? 2 - 0x1p-120f : 0x1p-120f * 0x1p-120f; +} -- cgit v1.2.3