include/fpu/softfloat-types.h

/*
 * QEMU float support
 *
 * The code in this source file is derived from release 2a of the SoftFloat
 * IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and
 * some later contributions) are provided under that license, as detailed below.
 * It has subsequently been modified by contributors to the QEMU Project,
 * so some portions are provided under:
 *  the SoftFloat-2a license
 *  the BSD license
 *  GPL-v2-or-later
 *
 * This header holds definitions for code that might be dealing with
 * softfloat types but not need access to the actual library functions.
 */
/*
===============================================================================
This C header file is part of the SoftFloat IEC/IEEE Floating-point
Arithmetic Package, Release 2a.

Written by John R. Hauser.  This work was made possible in part by the
International Computer Science Institute, located at Suite 600, 1947 Center
Street, Berkeley, California 94704.  Funding was partially provided by the
National Science Foundation under grant MIP-9311980.  The original version
of this code was written as part of a project to build a fixed-point vector
processor in collaboration with the University of California at Berkeley,
overseen by Profs. Nelson Morgan and John Wawrzynek.  More information
is available through the Web page `http://HTTP.CS.Berkeley.EDU/~jhauser/
arithmetic/SoftFloat.html'.

THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort
has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
TIMES RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO
PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.

Derivative works are acceptable, even for commercial purposes, so long as
(1) they include prominent notice that the work is derivative, and (2) they
include prominent notice akin to these four paragraphs for those parts of
this code that are retained.

===============================================================================
*/

/* BSD licensing:
 * Copyright (c) 2006, Fabrice Bellard
 * All rights reserved.
 *
 * 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.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
 */

/* Portions of this work are licensed under the terms of the GNU GPL,
 * version 2 or later. See the COPYING file in the top-level directory.
 */

#ifndef SOFTFLOAT_TYPES_H
#define SOFTFLOAT_TYPES_H

/* This 'flag' type must be able to hold at least 0 and 1. It should
 * probably be replaced with 'bool' but the uses would need to be audited
 * to check that they weren't accidentally relying on it being a larger type.
 */
typedef uint8_t flag;

/*
 * Software IEC/IEEE floating-point types.
 */

typedef uint16_t float16;
typedef uint32_t float32;
typedef uint64_t float64;
#define float16_val(x) (x)
#define float32_val(x) (x)
#define float64_val(x) (x)
#define make_float16(x) (x)
#define make_float32(x) (x)
#define make_float64(x) (x)
#define const_float16(x) (x)
#define const_float32(x) (x)
#define const_float64(x) (x)
typedef struct {
    uint64_t low;
    uint16_t high;
} floatx80;
#define make_floatx80(exp, mant) ((floatx80) { mant, exp })
#define make_floatx80_init(exp, mant) { .low = mant, .high = exp }
typedef struct {
#ifdef HOST_WORDS_BIGENDIAN
    uint64_t high, low;
#else
    uint64_t low, high;
#endif
} float128;
#define make_float128(high_, low_) ((float128) { .high = high_, .low = low_ })
#define make_float128_init(high_, low_) { .high = high_, .low = low_ }

/*
 * Software IEC/IEEE floating-point underflow tininess-detection mode.
 */

enum {
    float_tininess_after_rounding  = 0,
    float_tininess_before_rounding = 1
};

/*
 *Software IEC/IEEE floating-point rounding mode.
 */

enum {
    float_round_nearest_even = 0,
    float_round_down         = 1,
    float_round_up           = 2,
    float_round_to_zero      = 3,
    float_round_ties_away    = 4,
    /* Not an IEEE rounding mode: round to the closest odd mantissa value */
    float_round_to_odd       = 5,
};

/*
 * Software IEC/IEEE floating-point exception flags.
 */

enum {
    float_flag_invalid   =  1,
    float_flag_divbyzero =  4,
    float_flag_overflow  =  8,
    float_flag_underflow = 16,
    float_flag_inexact   = 32,
    float_flag_input_denormal = 64,
    float_flag_output_denormal = 128
};


/*
 * Floating Point Status. Individual architectures may maintain
 * several versions of float_status for different functions. The
 * correct status for the operation is then passed by reference to
 * most of the softfloat functions.
 */

typedef struct float_status {
    signed char float_detect_tininess;
    signed char float_rounding_mode;
    uint8_t     float_exception_flags;
    signed char floatx80_rounding_precision;
    /* should denormalised results go to zero and set the inexact flag? */
    flag flush_to_zero;
    /* should denormalised inputs go to zero and set the input_denormal flag? */
    flag flush_inputs_to_zero;
    flag default_nan_mode;
    /* not always used -- see snan_bit_is_one() in softfloat-specialize.h */
    flag snan_bit_is_one;
} float_status;

#endif /* SOFTFLOAT_TYPES_H */