first commit of the new libm!
[musl] / src / math / s_erff.c
diff --git a/src/math/s_erff.c b/src/math/s_erff.c
deleted file mode 100644 (file)
index 28e2f7b..0000000
+++ /dev/null
@@ -1,207 +0,0 @@
-/* s_erff.c -- float version of s_erf.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 <math.h>
-#include "math_private.h"
-
-static const float
-tiny        = 1e-30,
-half=  5.0000000000e-01, /* 0x3F000000 */
-one =  1.0000000000e+00, /* 0x3F800000 */
-two =  2.0000000000e+00, /* 0x40000000 */
-        /* c = (subfloat)0.84506291151 */
-erx =  8.4506291151e-01, /* 0x3f58560b */
-/*
- * Coefficients for approximation to  erf on [0,0.84375]
- */
-efx =  1.2837916613e-01, /* 0x3e0375d4 */
-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 */
-
-float
-erff(float x)
-{
-        int32_t hx,ix,i;
-        float R,S,P,Q,s,y,z,r;
-        GET_FLOAT_WORD(hx,x);
-        ix = hx&0x7fffffff;
-        if(ix>=0x7f800000) {            /* erf(nan)=nan */
-            i = ((uint32_t)hx>>31)<<1;
-            return (float)(1-i)+one/x;  /* erf(+-inf)=+-1 */
-        }
-
-        if(ix < 0x3f580000) {           /* |x|<0.84375 */
-            if(ix < 0x31800000) {       /* |x|<2**-28 */
-                if (ix < 0x04000000)
-                    /*avoid underflow */
-                    return (float)0.125*((float)8.0*x+efx8*x);
-                return x + efx*x;
-            }
-            z = x*x;
-            r = pp0+z*(pp1+z*(pp2+z*(pp3+z*pp4)));
-            s = one+z*(qq1+z*(qq2+z*(qq3+z*(qq4+z*qq5))));
-            y = r/s;
-            return x + x*y;
-        }
-        if(ix < 0x3fa00000) {           /* 0.84375 <= |x| < 1.25 */
-            s = fabsf(x)-one;
-            P = pa0+s*(pa1+s*(pa2+s*(pa3+s*(pa4+s*(pa5+s*pa6)))));
-            Q = one+s*(qa1+s*(qa2+s*(qa3+s*(qa4+s*(qa5+s*qa6)))));
-            if(hx>=0) return erx + P/Q; else return -erx - P/Q;
-        }
-        if (ix >= 0x40c00000) {         /* inf>|x|>=6 */
-            if(hx>=0) return one-tiny; else return tiny-one;
-        }
-        x = fabsf(x);
-        s = one/(x*x);
-        if(ix< 0x4036DB6E) {    /* |x| < 1/0.35 */
-            R=ra0+s*(ra1+s*(ra2+s*(ra3+s*(ra4+s*(
-                                ra5+s*(ra6+s*ra7))))));
-            S=one+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=one+s*(sb1+s*(sb2+s*(sb3+s*(sb4+s*(
-                                sb5+s*(sb6+s*sb7))))));
-        }
-        GET_FLOAT_WORD(ix,x);
-        SET_FLOAT_WORD(z,ix&0xfffff000);
-        r  =  expf(-z*z-(float)0.5625)*expf((z-x)*(z+x)+R/S);
-        if(hx>=0) return one-r/x; else return  r/x-one;
-}
-
-float
-erfcf(float x)
-{
-        int32_t hx,ix;
-        float R,S,P,Q,s,y,z,r;
-        GET_FLOAT_WORD(hx,x);
-        ix = hx&0x7fffffff;
-        if(ix>=0x7f800000) {                    /* erfc(nan)=nan */
-                                                /* erfc(+-inf)=0,2 */
-            return (float)(((uint32_t)hx>>31)<<1)+one/x;
-        }
-
-        if(ix < 0x3f580000) {           /* |x|<0.84375 */
-            if(ix < 0x23800000)         /* |x|<2**-56 */
-                return one-x;
-            z = x*x;
-            r = pp0+z*(pp1+z*(pp2+z*(pp3+z*pp4)));
-            s = one+z*(qq1+z*(qq2+z*(qq3+z*(qq4+z*qq5))));
-            y = r/s;
-            if(hx < 0x3e800000) {       /* x<1/4 */
-                return one-(x+x*y);
-            } else {
-                r = x*y;
-                r += (x-half);
-                return half - r ;
-            }
-        }
-        if(ix < 0x3fa00000) {           /* 0.84375 <= |x| < 1.25 */
-            s = fabsf(x)-one;
-            P = pa0+s*(pa1+s*(pa2+s*(pa3+s*(pa4+s*(pa5+s*pa6)))));
-            Q = one+s*(qa1+s*(qa2+s*(qa3+s*(qa4+s*(qa5+s*qa6)))));
-            if(hx>=0) {
-                z  = one-erx; return z - P/Q;
-            } else {
-                z = erx+P/Q; return one+z;
-            }
-        }
-        if (ix < 0x41e00000) {          /* |x|<28 */
-            x = fabsf(x);
-            s = one/(x*x);
-            if(ix< 0x4036DB6D) {        /* |x| < 1/.35 ~ 2.857143*/
-                R=ra0+s*(ra1+s*(ra2+s*(ra3+s*(ra4+s*(
-                                ra5+s*(ra6+s*ra7))))));
-                S=one+s*(sa1+s*(sa2+s*(sa3+s*(sa4+s*(
-                                sa5+s*(sa6+s*(sa7+s*sa8)))))));
-            } else {                    /* |x| >= 1/.35 ~ 2.857143 */
-                if(hx<0&&ix>=0x40c00000) return two-tiny;/* x < -6 */
-                R=rb0+s*(rb1+s*(rb2+s*(rb3+s*(rb4+s*(
-                                rb5+s*rb6)))));
-                S=one+s*(sb1+s*(sb2+s*(sb3+s*(sb4+s*(
-                                sb5+s*(sb6+s*sb7))))));
-            }
-            GET_FLOAT_WORD(ix,x);
-            SET_FLOAT_WORD(z,ix&0xfffff000);
-            r  =  expf(-z*z-(float)0.5625)*
-                        expf((z-x)*(z+x)+R/S);
-            if(hx>0) return r/x; else return two-r/x;
-        } else {
-            if(hx>0) return tiny*tiny; else return two-tiny;
-        }
-}