include/fpu/softfloat-types.h

   1 /*
   2  * QEMU float support
   3  *
   4  * The code in this source file is derived from release 2a of the SoftFloat
   5  * IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and
   6  * some later contributions) are provided under that license, as detailed below.
   7  * It has subsequently been modified by contributors to the QEMU Project,
   8  * so some portions are provided under:
   9  *  the SoftFloat-2a license
  10  *  the BSD license
  11  *  GPL-v2-or-later
  12  *
  13  * This header holds definitions for code that might be dealing with
  14  * softfloat types but not need access to the actual library functions.
  15  */
  16 /*
  17 ===============================================================================
  18 This C header file is part of the SoftFloat IEC/IEEE Floating-point
  19 Arithmetic Package, Release 2a.
  20
  21 Written by John R. Hauser.  This work was made possible in part by the
  22 International Computer Science Institute, located at Suite 600, 1947 Center
  23 Street, Berkeley, California 94704.  Funding was partially provided by the
  24 National Science Foundation under grant MIP-9311980.  The original version
  25 of this code was written as part of a project to build a fixed-point vector
  26 processor in collaboration with the University of California at Berkeley,
  27 overseen by Profs. Nelson Morgan and John Wawrzynek.  More information
  28 is available through the Web page `http://HTTP.CS.Berkeley.EDU/~jhauser/
  29 arithmetic/SoftFloat.html'.
  30
  31 THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort
  32 has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
  33 TIMES RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO
  34 PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
  35 AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
  36
  37 Derivative works are acceptable, even for commercial purposes, so long as
  38 (1) they include prominent notice that the work is derivative, and (2) they
  39 include prominent notice akin to these four paragraphs for those parts of
  40 this code that are retained.
  41
  42 ===============================================================================
  43 */
  44
  45 /* BSD licensing:
  46  * Copyright (c) 2006, Fabrice Bellard
  47  * All rights reserved.
  48  *
  49  * Redistribution and use in source and binary forms, with or without
  50  * modification, are permitted provided that the following conditions are met:
  51  *
  52  * 1. Redistributions of source code must retain the above copyright notice,
  53  * this list of conditions and the following disclaimer.
  54  *
  55  * 2. Redistributions in binary form must reproduce the above copyright notice,
  56  * this list of conditions and the following disclaimer in the documentation
  57  * and/or other materials provided with the distribution.
  58  *
  59  * 3. Neither the name of the copyright holder nor the names of its contributors
  60  * may be used to endorse or promote products derived from this software without
  61  * specific prior written permission.
  62  *
  63  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  64  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  65  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  66  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  67  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  68  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  69  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  70  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  71  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  72  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  73  * THE POSSIBILITY OF SUCH DAMAGE.
  74  */
  75
  76 /* Portions of this work are licensed under the terms of the GNU GPL,
  77  * version 2 or later. See the COPYING file in the top-level directory.
  78  */
  79
  80 #ifndef SOFTFLOAT_TYPES_H
  81 #define SOFTFLOAT_TYPES_H
  82
  83 /*
  84  * Software IEC/IEEE floating-point types.
  85  */
  86
  87 typedef uint16_t float16;
  88 typedef uint32_t float32;
  89 typedef uint64_t float64;
  90 #define float16_val(x) (x)
  91 #define float32_val(x) (x)
  92 #define float64_val(x) (x)
  93 #define make_float16(x) (x)
  94 #define make_float32(x) (x)
  95 #define make_float64(x) (x)
  96 #define const_float16(x) (x)
  97 #define const_float32(x) (x)
  98 #define const_float64(x) (x)
  99 typedef struct {
 100     uint64_t low;
 101     uint16_t high;
 102 } floatx80;
 103 #define make_floatx80(exp, mant) ((floatx80) { mant, exp })
 104 #define make_floatx80_init(exp, mant) { .low = mant, .high = exp }
 105 typedef struct {
 106 #if HOST_BIG_ENDIAN
 107     uint64_t high, low;
 108 #else
 109     uint64_t low, high;
 110 #endif
 111 } float128;
 112 #define make_float128(high_, low_) ((float128) { .high = high_, .low = low_ })
 113 #define make_float128_init(high_, low_) { .high = high_, .low = low_ }
 114
 115 /*
 116  * Software neural-network floating-point types.
 117  */
 118 typedef uint16_t bfloat16;
 119
 120 /*
 121  * Software IEC/IEEE floating-point underflow tininess-detection mode.
 122  */
 123
 124 #define float_tininess_after_rounding  false
 125 #define float_tininess_before_rounding true
 126
 127 /*
 128  *Software IEC/IEEE floating-point rounding mode.
 129  */
 130
 131 typedef enum __attribute__((__packed__)) {
 132     float_round_nearest_even = 0,
 133     float_round_down         = 1,
 134     float_round_up           = 2,
 135     float_round_to_zero      = 3,
 136     float_round_ties_away    = 4,
 137     /* Not an IEEE rounding mode: round to closest odd, overflow to max */
 138     float_round_to_odd       = 5,
 139     /* Not an IEEE rounding mode: round to closest odd, overflow to inf */
 140     float_round_to_odd_inf   = 6,
 141 } FloatRoundMode;
 142
 143 /*
 144  * Software IEC/IEEE floating-point exception flags.
 145  */
 146
 147 enum {
 148     float_flag_invalid         = 0x0001,
 149     float_flag_divbyzero       = 0x0002,
 150     float_flag_overflow        = 0x0004,
 151     float_flag_underflow       = 0x0008,
 152     float_flag_inexact         = 0x0010,
 153     float_flag_input_denormal  = 0x0020,
 154     float_flag_output_denormal = 0x0040,
 155     float_flag_invalid_isi     = 0x0080,  /* inf - inf */
 156     float_flag_invalid_imz     = 0x0100,  /* inf * 0 */
 157     float_flag_invalid_idi     = 0x0200,  /* inf / inf */
 158     float_flag_invalid_zdz     = 0x0400,  /* 0 / 0 */
 159     float_flag_invalid_sqrt    = 0x0800,  /* sqrt(-x) */
 160     float_flag_invalid_cvti    = 0x1000,  /* non-nan to integer */
 161     float_flag_invalid_snan    = 0x2000,  /* any operand was snan */
 162 };
 163
 164 /*
 165  * Rounding precision for floatx80.
 166  */
 167 typedef enum __attribute__((__packed__)) {
 168     floatx80_precision_x,
 169     floatx80_precision_d,
 170     floatx80_precision_s,
 171 } FloatX80RoundPrec;
 172
 173 /*
 174  * Floating Point Status. Individual architectures may maintain
 175  * several versions of float_status for different functions. The
 176  * correct status for the operation is then passed by reference to
 177  * most of the softfloat functions.
 178  */
 179
 180 typedef struct float_status {
 181     uint16_t float_exception_flags;
 182     FloatRoundMode float_rounding_mode;
 183     FloatX80RoundPrec floatx80_rounding_precision;
 184     bool tininess_before_rounding;
 185     /* should denormalised results go to zero and set the inexact flag? */
 186     bool flush_to_zero;
 187     /* should denormalised inputs go to zero and set the input_denormal flag? */
 188     bool flush_inputs_to_zero;
 189     bool default_nan_mode;
 190     /*
 191      * The flags below are not used on all specializations and may
 192      * constant fold away (see snan_bit_is_one()/no_signalling_nans() in
 193      * softfloat-specialize.inc.c)
 194      */
 195     bool snan_bit_is_one;
 196     bool use_first_nan;
 197     bool no_signaling_nans;
 198     /* should overflowed results subtract re_bias to its exponent? */
 199     bool rebias_overflow;
 200     /* should underflowed results add re_bias to its exponent? */
 201     bool rebias_underflow;
 202 } float_status;
 203
 204 #endif /* SOFTFLOAT_TYPES_H */