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Annotation of coherent/b/lib/libm/two.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * libm/two.c
        !             3:  * Evaluate 2 to the power x.
        !             4:  * (Hart 1067, 18.08)
        !             5:  */
        !             6: 
        !             7: #include <math.h>
        !             8: 
        !             9: #if    EMU87
        !            10: #include "emumath.h"
        !            11: #endif
        !            12: 
        !            13: static readonly double twontab[] ={
        !            14:        0.1513906799054338915894328e+04,
        !            15:        0.2020206565128692722788600e+02,
        !            16:        0.2309334775375023362400000e-01
        !            17: };
        !            18: static readonly double twomtab[] ={
        !            19:        0.4368211662727558498496814e+04,
        !            20:        0.2331842114274816237902950e+03,
        !            21:        0.1000000000000000000000000e+01
        !            22: };
        !            23: 
        !            24: double
        !            25: _two(x) double x;
        !            26: {
        !            27:        double p, q, r, e;
        !            28:        register int s;
        !            29: 
        !            30:        if (x > L2HUGE_VAL) {
        !            31:                errno = ERANGE;
        !            32:                return HUGE_VAL;
        !            33:        }
        !            34:        s = 0;
        !            35:        if ((x = modf(x, &e)) < 0.0) {
        !            36:                x += 1.0;
        !            37:                e -= 1.0;
        !            38:        }
        !            39:        if (x > 0.5) {
        !            40:                s = 1;
        !            41:                x -= 0.5;
        !            42:        }
        !            43:        r = x*x;
        !            44:        p = x*_pol(r, twontab, 3);
        !            45:        q = _pol(r, twomtab, 3);
        !            46:        r = (q+p)/(q-p);
        !            47:        if (s)
        !            48:                r *= SQRT2;
        !            49:        return ldexp(r, (int) e);
        !            50: }
        !            51: 
        !            52: /* end of libm/two.c */

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