/*      $NetBSD: floatdisf_ieee754.c,v 1.2 2013/08/24 00:51:48 matt Exp $       */

/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: floatdisf_ieee754.c,v 1.2 2013/08/24 00:51:48 matt Exp $");
#endif /* LIBC_SCCS and not lint */

#if defined(SOFTFLOAT) || defined(__ARM_EABI__)
#include "softfloat/softfloat-for-gcc.h"
#endif

#include <limits.h>
#include <machine/ieee.h>
#include "quad.h"

float __floatdisf(quad_t);

/*
* Convert signed quad to float.
*/
float
__floatdisf(quad_t x)
{
       union ieee_single_u ux = { .sngu_f = 0.0 };

       if (x == 0)
               return 0.0;
       if (x == 1)
               return 1.0;

       if (x < 0) {
               if (x == QUAD_MIN)
                       return -0x1.0p63;
               ux.sngu_sign = 1;
               x = -x;
       }
#if defined(_LP64) || defined(__mips_n32)
       u_int l = __builtin_clzll(x);
       x <<= (l + 1);  /* clear implicit bit */

       ux.sngu_frac = (u_quad_t)x >> (64 - SNG_FRACBITS);
#else
       union uu u = { .uq = x };
       uint32_t frac;
       u_int l;
       if (u.ul[H] == 0) {
               l = __builtin_clz(u.ul[L]);
               frac = u.ul[L] << (l + 1);      /* clear implicit bit */
               l += 32;
       } else {
               l = __builtin_clz(u.ul[H]);
               frac = u.ul[H] << (l + 1);      /* clear implicit bit */
               frac |= u.ul[L] >> (32 - (l + 1));
       }

       ux.sngu_frac = frac >> (32 - SNG_FRACBITS);
#endif
       ux.sngu_exp = SNG_EXP_BIAS + 63 - l;

       return ux.sngu_f;
}