sys/arch/i386/include/fenv.h

   1 /*      $NetBSD: fenv.h,v 1.1 2010/07/31 21:47:54 joerg Exp $   */
   2 /*-
   3  * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #ifndef _X86_FENV_H_
  29 #define _X86_FENV_H_
  30
  31 #include <sys/stdint.h>
  32 #include <i386/npx.h>
  33
  34 /*
  35  * Each symbol representing a floating point exception expands to an integer
  36  * constant expression with values, such that bitwise-inclusive ORs of _all
  37  * combinations_ of the constants result in distinct values.
  38  *
  39  * We use such values that allow direct bitwise operations on FPU/SSE registers.
  40  */
  41 #define FE_INVALID      0x01    /* 000000000001 */
  42 #define FE_DENORMAL     0x02    /* 000000000010 */
  43 #define FE_DIVBYZERO    0x04    /* 000000000100 */
  44 #define FE_OVERFLOW     0x08    /* 000000001000 */
  45 #define FE_UNDERFLOW    0x10    /* 000000010000 */
  46 #define FE_INEXACT      0x20    /* 000000100000 */
  47
  48 /*
  49  * The following symbol is simply the bitwise-inclusive OR of all floating-point
  50  * exception constants defined above.
  51  */
  52 #define FE_ALL_EXCEPT   (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \
  53                          FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
  54
  55 /*
  56  * Each symbol representing the rounding direction, expands to an integer
  57  * constant expression whose value is distinct non-negative value.
  58  *
  59  * We use such values that allow direct bitwise operations on FPU/SSE registers.
  60  */
  61 #define FE_TONEAREST    0x000   /* 000000000000 */
  62 #define FE_DOWNWARD     0x400   /* 010000000000 */
  63 #define FE_UPWARD       0x800   /* 100000000000 */
  64 #define FE_TOWARDZERO   0xC00   /* 110000000000 */
  65
  66 /*
  67  * As compared to the x87 control word, the SSE unit's control has the rounding
  68  * control bits offset by 3 and the exception mask bits offset by 7
  69  */
  70 #define __X87_ROUND_MASK        0xC00           /* 110000000000 */
  71 #define __SSE_ROUND_SHIFT       3
  72 #define __SSE_EMASK_SHIFT       7
  73
  74 /*
  75  * fenv_t represents the entire floating-point environment
  76  */
  77 typedef struct {
  78         struct {
  79                 uint16_t control;       /* Control word register */
  80                 uint16_t unused1;
  81                 uint16_t status;        /* Status word register */
  82                 uint16_t unused2;
  83                 uint16_t tag;           /* Tag word register */
  84                 uint16_t unused3;
  85                 uint32_t others[4];     /* EIP, Pointer Selector, etc */
  86         } x87;
  87
  88         uint32_t mxcsr;                 /* Control and status register */
  89 } fenv_t;
  90
  91 /*
  92  * The following constant represents the default floating-point environment
  93  * (that is, the one installed at program startup) and has type pointer to
  94  * const-qualified fenv_t.
  95  *
  96  * It can be used as an argument to the functions within the <fenv.h> header
  97  * that manage the floating-point environment.
  98  */
  99 extern  fenv_t          __fe_dfl_env;
 100 #define FE_DFL_ENV      ((const fenv_t *) &__fe_dfl_env)
 101
 102 /*
 103  * fexcept_t represents the floating-point status flags collectively, including
 104  * any status the implementation associates with the flags.
 105  *
 106  * A floating-point status flag is a system variable whose value is set (but
 107  * never cleared) when a floating-point exception is raised, which occurs as a
 108  * side effect of exceptional floating-point arithmetic to provide auxiliary
 109  * information.
 110  *
 111  * A floating-point control mode is a system variable whose value may be set by
 112  * the user to affect the subsequent behavior of floating-point arithmetic.
 113  */
 114 typedef uint32_t fexcept_t;
 115
 116 #endif  /* ! _X86_FENV_H_ */