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Annotation of coherent/b/lib/libc/gen/ieee_f.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * libc/gen/ieee_f.c
        !             3:  */
        !             4: 
        !             5: /*
        !             6:  * ieee_f(float *ifp, float *dfp)
        !             7:  * Convert float from DECVAX format to IEEE format.
        !             8:  * dfp points to a DECVAX format float to convert.
        !             9:  * ifp points to a destination for the converted IEEE value;
        !            10:  * ifp may be identical to dfp for in-place conversion.
        !            11:  * The significand remains unchanged.
        !            12:  * Returns 0 if successful, -1 on underflow.
        !            13:  */
        !            14: 
        !            15: int
        !            16: ieee_f(ifp, dfp) float *ifp, *dfp;
        !            17: {
        !            18:        register int exp;
        !            19:        register unsigned char *cp;
        !            20: 
        !            21:        /* Copy to destination. */
        !            22:        cp = (char *)ifp;
        !            23:        if (ifp != dfp)
        !            24:                memcpy(cp, (char *)dfp, sizeof(float));
        !            25: 
        !            26:        /* Adjust exponent bias from 129 to 127. */
        !            27:        exp = ((cp[3] & 0x7F) << 1) | ((cp[2] & 0x80) >> 7);
        !            28:        if (exp == 0)
        !            29:                return 0;
        !            30:        else if (exp > 2) {
        !            31:                /* Subtract 2 by decrementing the low bit of the hi byte. */
        !            32:                --cp[3];
        !            33:                return 0;
        !            34:        }
        !            35: 
        !            36:        /* Exponent underflow. */
        !            37:        cp[3] = cp[2] = cp[1] = cp[0] = 0;
        !            38:        return -1;
        !            39: }
        !            40: 
        !            41: /* end of libc/gen/ieee_f.c */

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