181 lines
6.5 KiB
C
181 lines
6.5 KiB
C
/*
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* QEMU float support
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*
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* The code in this source file is derived from release 2a of the SoftFloat
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* IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and
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* some later contributions) are provided under that license, as detailed below.
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* It has subsequently been modified by contributors to the QEMU Project,
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* so some portions are provided under:
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* the SoftFloat-2a license
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* the BSD license
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* GPL-v2-or-later
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*
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* This header holds definitions for code that might be dealing with
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* softfloat types but not need access to the actual library functions.
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*/
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/*
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===============================================================================
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This C header file is part of the SoftFloat IEC/IEEE Floating-point
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Arithmetic Package, Release 2a.
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Written by John R. Hauser. This work was made possible in part by the
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International Computer Science Institute, located at Suite 600, 1947 Center
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Street, Berkeley, California 94704. Funding was partially provided by the
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National Science Foundation under grant MIP-9311980. The original version
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of this code was written as part of a project to build a fixed-point vector
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processor in collaboration with the University of California at Berkeley,
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overseen by Profs. Nelson Morgan and John Wawrzynek. More information
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is available through the Web page `http://HTTP.CS.Berkeley.EDU/~jhauser/
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arithmetic/SoftFloat.html'.
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THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort
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has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
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TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO
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PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
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AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
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Derivative works are acceptable, even for commercial purposes, so long as
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(1) they include prominent notice that the work is derivative, and (2) they
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include prominent notice akin to these four paragraphs for those parts of
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this code that are retained.
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===============================================================================
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*/
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/* BSD licensing:
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* Copyright (c) 2006, Fabrice Bellard
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* Portions of this work are licensed under the terms of the GNU GPL,
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* version 2 or later. See the COPYING file in the top-level directory.
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*/
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#ifndef SOFTFLOAT_TYPES_H
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#define SOFTFLOAT_TYPES_H
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/* This 'flag' type must be able to hold at least 0 and 1. It should
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* probably be replaced with 'bool' but the uses would need to be audited
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* to check that they weren't accidentally relying on it being a larger type.
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*/
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typedef uint8_t flag;
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/*
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* Software IEC/IEEE floating-point types.
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*/
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typedef uint16_t float16;
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typedef uint32_t float32;
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typedef uint64_t float64;
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#define float16_val(x) (x)
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#define float32_val(x) (x)
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#define float64_val(x) (x)
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#define make_float16(x) (x)
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#define make_float32(x) (x)
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#define make_float64(x) (x)
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#define const_float16(x) (x)
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#define const_float32(x) (x)
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#define const_float64(x) (x)
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typedef struct {
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uint64_t low;
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uint16_t high;
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} floatx80;
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#define make_floatx80(exp, mant) ((floatx80) { mant, exp })
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#define make_floatx80_init(exp, mant) { .low = mant, .high = exp }
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typedef struct {
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#ifdef HOST_WORDS_BIGENDIAN
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uint64_t high, low;
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#else
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uint64_t low, high;
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#endif
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} float128;
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#define make_float128(high_, low_) ((float128) { .high = high_, .low = low_ })
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#define make_float128_init(high_, low_) { .high = high_, .low = low_ }
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/*
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* Software IEC/IEEE floating-point underflow tininess-detection mode.
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*/
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enum {
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float_tininess_after_rounding = 0,
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float_tininess_before_rounding = 1
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};
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/*
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*Software IEC/IEEE floating-point rounding mode.
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*/
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enum {
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float_round_nearest_even = 0,
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float_round_down = 1,
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float_round_up = 2,
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float_round_to_zero = 3,
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float_round_ties_away = 4,
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/* Not an IEEE rounding mode: round to the closest odd mantissa value */
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float_round_to_odd = 5,
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};
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/*
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* Software IEC/IEEE floating-point exception flags.
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*/
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enum {
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float_flag_invalid = 1,
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float_flag_divbyzero = 4,
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float_flag_overflow = 8,
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float_flag_underflow = 16,
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float_flag_inexact = 32,
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float_flag_input_denormal = 64,
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float_flag_output_denormal = 128
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};
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/*
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* Floating Point Status. Individual architectures may maintain
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* several versions of float_status for different functions. The
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* correct status for the operation is then passed by reference to
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* most of the softfloat functions.
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*/
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typedef struct float_status {
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signed char float_detect_tininess;
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signed char float_rounding_mode;
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uint8_t float_exception_flags;
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signed char floatx80_rounding_precision;
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/* should denormalised results go to zero and set the inexact flag? */
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flag flush_to_zero;
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/* should denormalised inputs go to zero and set the input_denormal flag? */
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flag flush_inputs_to_zero;
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flag default_nan_mode;
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/* not always used -- see snan_bit_is_one() in softfloat-specialize.h */
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flag snan_bit_is_one;
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} float_status;
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#endif /* SOFTFLOAT_TYPES_H */
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