/*      $NetBSD: fcnvxf.c,v 1.4 2012/02/04 17:03:10 skrll Exp $ */

/*      $OpenBSD: fcnvxf.c,v 1.5 2001/03/29 03:58:18 mickey Exp $       */

/*
 * Copyright 1996 1995 by Open Software Foundation, Inc.
 *              All Rights Reserved
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appears in all copies and
 * that both the copyright notice and this permission notice appear in
 * supporting documentation.
 *
 * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */
/*
 * pmk1.1
 */
/*
 * (c) Copyright 1986 HEWLETT-PACKARD COMPANY
 *
 * To anyone who acknowledges that this file is provided "AS IS"
 * without any express or implied warranty:
 *     permission to use, copy, modify, and distribute this file
 * for any purpose is hereby granted without fee, provided that
 * the above copyright notice and this notice appears in all
 * copies, and that the name of Hewlett-Packard Company not be
 * used in advertising or publicity pertaining to distribution
 * of the software without specific, written prior permission.
 * Hewlett-Packard Company makes no representations about the
 * suitability of this software for any purpose.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fcnvxf.c,v 1.4 2012/02/04 17:03:10 skrll Exp $");

#include "../spmath/float.h"
#include "../spmath/sgl_float.h"
#include "../spmath/dbl_float.h"
#include "../spmath/cnv_float.h"

/*
 *  Convert single fixed-point to single floating-point format
 */
int
sgl_to_sgl_fcnvxf(int *srcptr, sgl_floating_point *dstptr,
    unsigned int *status)
{
        register int src, dst_exponent;
        register unsigned int result = 0;

        src = *srcptr;
        /*
         * set sign bit of result and get magnitude of source
         */
        if (src < 0) {
                Sgl_setone_sign(result);
                Int_negate(src);
        }
        else {
                Sgl_setzero_sign(result);
                /* Check for zero */
                if (src == 0) {
                        Sgl_setzero(result);
                        *dstptr = result;
                        return(NOEXCEPTION);
                }
        }
        /*
         * Generate exponent and normalized mantissa
         */
        dst_exponent = 16;    /* initialize for normalization */
        /*
         * Check word for most significant bit set.  Returns
         * a value in dst_exponent indicating the bit position,
         * between -1 and 30.
         */
        Find_ms_one_bit(src,dst_exponent);
        /*  left justify source, with msb at bit position 1  */
        if (dst_exponent >= 0) src <<= dst_exponent;
        else src = 1 << 30;
        Sgl_set_mantissa(result, src >> (SGL_EXP_LENGTH-1));
        Sgl_set_exponent(result, 30+SGL_BIAS - dst_exponent);

        /* check for inexact */
        if (Int_isinexact_to_sgl(src)) {
                switch (Rounding_mode()) {
                        case ROUNDPLUS:
                                if (Sgl_iszero_sign(result))
                                        Sgl_increment(result);
                                break;
                        case ROUNDMINUS:
                                if (Sgl_isone_sign(result))
                                        Sgl_increment(result);
                                break;
                        case ROUNDNEAREST:
                                Sgl_roundnearest_from_int(src,result);
                }
                if (Is_inexacttrap_enabled()) {
                        *dstptr = result;
                        return(INEXACTEXCEPTION);
                }
                else Set_inexactflag();
        }
        *dstptr = result;
        return(NOEXCEPTION);
}

/*
 *  Single Fixed-point to Double Floating-point
 */
int
sgl_to_dbl_fcnvxf(int *srcptr, dbl_floating_point *dstptr,
    unsigned int *status)
{
        register int src, dst_exponent;
        register unsigned int resultp1 = 0, resultp2 = 0;

        src = *srcptr;
        /*
         * set sign bit of result and get magnitude of source
         */
        if (src < 0) {
                Dbl_setone_sign(resultp1);
                Int_negate(src);
        }
        else {
                Dbl_setzero_sign(resultp1);
                /* Check for zero */
                if (src == 0) {
                        Dbl_setzero(resultp1,resultp2);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        return(NOEXCEPTION);
                }
        }
        /*
         * Generate exponent and normalized mantissa
         */
        dst_exponent = 16;    /* initialize for normalization */
        /*
         * Check word for most significant bit set.  Returns
         * a value in dst_exponent indicating the bit position,
         * between -1 and 30.
         */
        Find_ms_one_bit(src,dst_exponent);
        /*  left justify source, with msb at bit position 1  */
        if (dst_exponent >= 0) src <<= dst_exponent;
        else src = 1 << 30;
        Dbl_set_mantissap1(resultp1, (src >> (DBL_EXP_LENGTH - 1)));
        Dbl_set_mantissap2(resultp2, (src << (33-DBL_EXP_LENGTH)));
        Dbl_set_exponent(resultp1, (30+DBL_BIAS) - dst_exponent);
        Dbl_copytoptr(resultp1,resultp2,dstptr);
        return(NOEXCEPTION);
}

/*
 *  Double Fixed-point to Single Floating-point
 */
int
dbl_to_sgl_fcnvxf(dbl_integer *srcptr, sgl_floating_point *dstptr,
    unsigned int *status)
{
        int dst_exponent, srcp1;
        unsigned int result = 0, srcp2;

        Dint_copyfromptr(srcptr,srcp1,srcp2);
        /*
         * set sign bit of result and get magnitude of source
         */
        if (srcp1 < 0) {
                Sgl_setone_sign(result);
                Dint_negate(srcp1,srcp2);
        }
        else {
                Sgl_setzero_sign(result);
                /* Check for zero */
                if (srcp1 == 0 && srcp2 == 0) {
                        Sgl_setzero(result);
                        *dstptr = result;
                        return(NOEXCEPTION);
                }
        }
        /*
         * Generate exponent and normalized mantissa
         */
        dst_exponent = 16;    /* initialize for normalization */
        if (srcp1 == 0) {
                /*
                 * Check word for most significant bit set.  Returns
                 * a value in dst_exponent indicating the bit position,
                 * between -1 and 30.
                 */
                Find_ms_one_bit(srcp2,dst_exponent);
                /*  left justify source, with msb at bit position 1  */
                if (dst_exponent >= 0) {
                        srcp1 = srcp2 << dst_exponent;
                        srcp2 = 0;
                }
                else {
                        srcp1 = srcp2 >> 1;
                        srcp2 <<= 31;
                }
                /*
                 *  since msb set is in second word, need to
                 *  adjust bit position count
                 */
                dst_exponent += 32;
        }
        else {
                /*
                 * Check word for most significant bit set.  Returns
                 * a value in dst_exponent indicating the bit position,
                 * between -1 and 30.
                 *
                 */
                Find_ms_one_bit(srcp1,dst_exponent);
                /*  left justify source, with msb at bit position 1  */
                if (dst_exponent > 0) {
                        Variable_shift_double(srcp1,srcp2,(32-dst_exponent),
                         srcp1);
                        srcp2 <<= dst_exponent;
                }
                /*
                 * If dst_exponent = 0, we don't need to shift anything.
                 * If dst_exponent = -1, src = - 2**63 so we won't need to
                 * shift srcp2.
                 */
                else srcp1 >>= -(dst_exponent);
        }
        Sgl_set_mantissa(result, (srcp1 >> (SGL_EXP_LENGTH - 1)));
        Sgl_set_exponent(result, (62+SGL_BIAS) - dst_exponent);

        /* check for inexact */
        if (Dint_isinexact_to_sgl(srcp1,srcp2)) {
                switch (Rounding_mode()) {
                        case ROUNDPLUS:
                                if (Sgl_iszero_sign(result))
                                        Sgl_increment(result);
                                break;
                        case ROUNDMINUS:
                                if (Sgl_isone_sign(result))
                                        Sgl_increment(result);
                                break;
                        case ROUNDNEAREST:
                                Sgl_roundnearest_from_dint(srcp1,srcp2,result);
                }
                if (Is_inexacttrap_enabled()) {
                        *dstptr = result;
                        return(INEXACTEXCEPTION);
                }
                else Set_inexactflag();
        }
        *dstptr = result;
        return(NOEXCEPTION);
}

/*
 *  Double Fixed-point to Double Floating-point
 */
int
dbl_to_dbl_fcnvxf(dbl_integer *srcptr, dbl_floating_point *dstptr,
    unsigned int *status)
{
        register int srcp1, dst_exponent;
        register unsigned int srcp2, resultp1 = 0, resultp2 = 0;

        Dint_copyfromptr(srcptr,srcp1,srcp2);
        /*
         * set sign bit of result and get magnitude of source
         */
        if (srcp1 < 0) {
                Dbl_setone_sign(resultp1);
                Dint_negate(srcp1,srcp2);
        }
        else {
                Dbl_setzero_sign(resultp1);
                /* Check for zero */
                if (srcp1 == 0 && srcp2 ==0) {
                        Dbl_setzero(resultp1,resultp2);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        return(NOEXCEPTION);
                }
        }
        /*
         * Generate exponent and normalized mantissa
         */
        dst_exponent = 16;    /* initialize for normalization */
        if (srcp1 == 0) {
                /*
                 * Check word for most significant bit set.  Returns
                 * a value in dst_exponent indicating the bit position,
                 * between -1 and 30.
                 */
                Find_ms_one_bit(srcp2,dst_exponent);
                /*  left justify source, with msb at bit position 1  */
                if (dst_exponent >= 0) {
                        srcp1 = srcp2 << dst_exponent;
                        srcp2 = 0;
                }
                else {
                        srcp1 = srcp2 >> 1;
                        srcp2 <<= 31;
                }
                /*
                 *  since msb set is in second word, need to
                 *  adjust bit position count
                 */
                dst_exponent += 32;
        }
        else {
                /*
                 * Check word for most significant bit set.  Returns
                 * a value in dst_exponent indicating the bit position,
                 * between -1 and 30.
                 */
                Find_ms_one_bit(srcp1,dst_exponent);
                /*  left justify source, with msb at bit position 1  */
                if (dst_exponent > 0) {
                        Variable_shift_double(srcp1,srcp2,(32-dst_exponent),
                         srcp1);
                        srcp2 <<= dst_exponent;
                }
                /*
                 * If dst_exponent = 0, we don't need to shift anything.
                 * If dst_exponent = -1, src = - 2**63 so we won't need to
                 * shift srcp2.
                 */
                else srcp1 >>= -(dst_exponent);
        }
        Dbl_set_mantissap1(resultp1, srcp1 >> (DBL_EXP_LENGTH-1));
        Shiftdouble(srcp1,srcp2,DBL_EXP_LENGTH-1,resultp2);
        Dbl_set_exponent(resultp1, (62+DBL_BIAS) - dst_exponent);

        /* check for inexact */
        if (Dint_isinexact_to_dbl(srcp2)) {
                switch (Rounding_mode()) {
                        case ROUNDPLUS:
                                if (Dbl_iszero_sign(resultp1)) {
                                        Dbl_increment(resultp1,resultp2);
                                }
                                break;
                        case ROUNDMINUS:
                                if (Dbl_isone_sign(resultp1)) {
                                        Dbl_increment(resultp1,resultp2);
                                }
                                break;
                        case ROUNDNEAREST:
                                Dbl_roundnearest_from_dint(srcp2,resultp1,
                                resultp2);
                }
                if (Is_inexacttrap_enabled()) {
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        return(INEXACTEXCEPTION);
                }
                else Set_inexactflag();
        }
        Dbl_copytoptr(resultp1,resultp2,dstptr);
        return(NOEXCEPTION);
}