sys/arch/x86/include/ieee.h

   1 /*      $NetBSD: ieee.h,v 1.11 2010/09/15 16:11:28 christos Exp $ */
   2
   3 /*
   4  * Copyright (c) 1992, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This software was developed by the Computer Systems Engineering group
   8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   9  * contributed to Berkeley.
  10  *
  11  * All advertising materials mentioning features or use of this software
  12  * must display the following acknowledgement:
  13  *      This product includes software developed by the University of
  14  *      California, Lawrence Berkeley Laboratory.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  * 3. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  *
  40  *      @(#)ieee.h      8.1 (Berkeley) 6/11/93
  41  */
  42
  43 /*
  44  * ieee.h defines the machine-dependent layout of the machine's IEEE
  45  * floating point.  It does *not* define (yet?) any of the rounding
  46  * mode bits, exceptions, and so forth.
  47  */
  48
  49 #include <sys/ieee754.h>
  50
  51 #define EXT_EXPBITS     15
  52 #define EXT_FRACHBITS   32
  53 #define EXT_FRACLBITS   32
  54 #define EXT_FRACBITS    (EXT_FRACLBITS + EXT_FRACHBITS)
  55
  56 #define EXT_TO_ARRAY32(u, a) do {                       \
  57         (a)[0] = (uint32_t)(u).extu_ext.ext_fracl;      \
  58         (a)[1] = (uint32_t)(u).extu_ext.ext_frach;      \
  59 } while(/*CONSTCOND*/0)
  60
  61 /*
  62  * struct ieee_ext is the raw storage layout of the 80-bit
  63  * extended-precision type as implemented by the FPU.  Per the
  64  * respective ABI specifications, it is followed by a tail padding of
  65  *
  66  *   amd64: 48 bits,
  67  *   i386:  16 bits.
  68  */
  69 struct ieee_ext {
  70         u_int   ext_fracl:EXT_FRACLBITS;
  71         u_int   ext_frach:EXT_FRACHBITS;
  72 #if 0
  73         u_int   ext_int:1;
  74 #endif
  75         u_int   ext_exp:EXT_EXPBITS;
  76         u_int   ext_sign:1;
  77 };
  78
  79 /*
  80  * Floats whose exponent is in [1..INFNAN) (of whatever type) are
  81  * `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
  82  * Floats whose exponent is zero are either zero (iff all fraction
  83  * bits are zero) or subnormal values.
  84  *
  85  * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
  86  * high fraction; if the bit is set, it is a `quiet NaN'.
  87  */
  88 #define EXT_EXP_INFNAN  0x7fff
  89 #define EXT_EXP_INF     0x7fff
  90 #define EXT_EXP_NAN     0x7fff
  91
  92 #if 0
  93 #define SNG_QUIETNAN    (1 << 22)
  94 #define DBL_QUIETNAN    (1 << 19)
  95 #define EXT_QUIETNAN    (1 << 30)
  96 #endif
  97
  98 /*
  99  * Exponent biases.
 100  */
 101 #define EXT_EXP_BIAS    16383
 102
 103 /*
 104  * Convenience data structures.
 105  */
 106 union ieee_ext_u {
 107         long double             extu_ld;
 108         struct ieee_ext         extu_ext;
 109 };
 110
 111 #define extu_exp        extu_ext.ext_exp
 112 #define extu_sign       extu_ext.ext_sign
 113 #define extu_fracl      extu_ext.ext_fracl
 114 #define extu_frach      extu_ext.ext_frach
 115
 116 #define LDBL_NBIT       0x80000000
 117 #define mask_nbit_l(u)  ((u).extu_frach &= ~LDBL_NBIT)