port/fp/fconvert.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "lint.h"
#include "base_conversion.h"
#include <sys/types.h>
#include "libc.h"

char *
fconvert(double arg, int ndigits, int *decpt, int *sign, char *buf)
{
    decimal_mode    dm;
    decimal_record  dr;
    fp_exception_field_type ef;
    int     i;

#if defined(__sparc)
    dm.rd = _QgetRD();
#elif defined(__i386) || defined(__amd64)
    dm.rd = __xgetRD();
#else
#error Unknown architecture
#endif
    dm.df = fixed_form; /* F format. */
    if (ndigits <= -DECIMAL_STRING_LENGTH)
        ndigits = -DECIMAL_STRING_LENGTH + 1;
    else if (ndigits >= DECIMAL_STRING_LENGTH)
        ndigits = DECIMAL_STRING_LENGTH - 1;
    dm.ndigits = ndigits;   /* Number of digits after point. */
    double_to_decimal(&arg, &dm, &dr, &ef);
    *sign = dr.sign;
    switch (dr.fpclass) {
    case fp_normal:
    case fp_subnormal:
        *decpt = dr.exponent + dr.ndigits;
        for (i = 0; i < dr.ndigits; i++)
            buf[i] = dr.ds[i];
        /*
         * Pad with zeroes if we didn't get all the digits
         * we asked for.
         */
        if (ndigits > 0 && dr.exponent > -ndigits) {
            while (i < dr.ndigits + dr.exponent + ndigits)
                buf[i++] = '0';
        }
        buf[i] = 0;
        break;
    case fp_zero:
        *decpt = 0;
        buf[0] = '0';
        for (i = 1; i < ndigits; i++)
            buf[i] = '0';
        buf[i] = 0;
        break;
    default:
        *decpt = 0;
        __infnanstring(dr.fpclass, ndigits, buf);
        break;
    }
    return (buf);
}

char *
sfconvert(single *arg, int ndigits, int *decpt, int *sign, char *buf)
{
    decimal_mode    dm;
    decimal_record  dr;
    fp_exception_field_type ef;
    int     i;

#if defined(__sparc)
    dm.rd = _QgetRD();
#elif defined(__i386) || defined(__amd64)
    dm.rd = __xgetRD();
#else
#error Unknown architecture
#endif
    dm.df = fixed_form; /* F format. */
    if (ndigits <= -DECIMAL_STRING_LENGTH)
        ndigits = -DECIMAL_STRING_LENGTH + 1;
    else if (ndigits >= DECIMAL_STRING_LENGTH)
        ndigits = DECIMAL_STRING_LENGTH - 1;
    dm.ndigits = ndigits;   /* Number of digits after point. */
    single_to_decimal(arg, &dm, &dr, &ef);
    *sign = dr.sign;
    switch (dr.fpclass) {
    case fp_normal:
    case fp_subnormal:
        *decpt = dr.exponent + dr.ndigits;
        for (i = 0; i < dr.ndigits; i++)
            buf[i] = dr.ds[i];
        /*
         * Pad with zeroes if we didn't get all the digits
         * we asked for.
         */
        if (ndigits > 0 && dr.exponent > -ndigits) {
            while (i < dr.ndigits + dr.exponent + ndigits)
                buf[i++] = '0';
        }
        buf[i] = 0;
        break;
    case fp_zero:
        *decpt = 0;
        buf[0] = '0';
        for (i = 1; i < ndigits; i++)
            buf[i] = '0';
        buf[i] = 0;
        break;
    default:
        *decpt = 0;
        __infnanstring(dr.fpclass, ndigits, buf);
        break;
    }
    return (buf);
}

char *
qfconvert(quadruple *arg, int ndigits, int *decpt, int *sign, char *buf)
{
    decimal_mode    dm;
    decimal_record  dr;
    fp_exception_field_type ef;
    int     i;

#if defined(__sparc)
    dm.rd = _QgetRD();
#elif defined(__i386) || defined(__amd64)
    dm.rd = __xgetRD();
#else
#error Unknown architecture
#endif
    dm.df = fixed_form; /* F format. */
    if (ndigits <= -DECIMAL_STRING_LENGTH)
        ndigits = -DECIMAL_STRING_LENGTH + 1;
    else if (ndigits >= DECIMAL_STRING_LENGTH)
        ndigits = DECIMAL_STRING_LENGTH - 1;
    dm.ndigits = ndigits;   /* Number of digits after point. */
#if defined(__sparc)
    quadruple_to_decimal(arg, &dm, &dr, &ef);
#elif defined(__i386) || defined(__amd64)
    extended_to_decimal((extended *)arg, &dm, &dr, &ef);
#else
#error Unknown architecture
#endif
    *sign = dr.sign;
    if (ef & (1 << fp_overflow)) {
        /*
         * *_to_decimal raises overflow whenever dr.ds isn't large
         * enough to hold all the digits requested.  For float and
         * double, this can only happen when the requested format
         * would require trailing zeroes, in which case fconvert
         * and sfconvert just add them.  For long double, the arg-
         * ument might be large enough that even the nonzero digits
         * would overflow dr.ds, so we punt instead.  (We could
         * distinguish these two cases, but it doesn't seem worth
         * changing things now, particularly since no real appli-
         * cation prints floating point numbers to 500 digits.)
         */
        *decpt = 0;
        buf[0] = 0;
        return (buf);
    }
    switch (dr.fpclass) {
    case fp_normal:
    case fp_subnormal:
        *decpt = dr.exponent + dr.ndigits;
        for (i = 0; i < dr.ndigits; i++)
            buf[i] = dr.ds[i];
        buf[i] = 0;
        break;
    case fp_zero:
        *decpt = 0;
        buf[0] = '0';
        for (i = 1; i < ndigits; i++)
            buf[i] = '0';
        buf[i] = 0;
        break;
    default:
        *decpt = 0;
        __infnanstring(dr.fpclass, ndigits, buf);
        break;
    }
    return (buf);
}