FreeBSD/Linux Kernel Cross Reference
sys/i386/include/npx.h

     /*-
      * Copyright (c) 1990 The Regents of the University of California.
      * All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * William Jolitz.
      *
      * 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. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
     *
     *      from: @(#)npx.h 5.3 (Berkeley) 1/18/91
     * $FreeBSD$
     */
    
    /*
     * 287/387 NPX Coprocessor Data Structures and Constants
     * W. Jolitz 1/90
     */
    
    #ifndef _MACHINE_NPX_H_
    #define _MACHINE_NPX_H_
    
    /* Environment information of floating point unit */
    struct  env87 {
            long    en_cw;          /* control word (16bits) */
            long    en_sw;          /* status word (16bits) */
            long    en_tw;          /* tag word (16bits) */
            long    en_fip;         /* floating point instruction pointer */
            u_short en_fcs;         /* floating code segment selector */
            u_short en_opcode;      /* opcode last executed (11 bits ) */
            long    en_foo;         /* floating operand offset */
            long    en_fos;         /* floating operand segment selector */
    };
    
    /* Contents of each floating point accumulator */
    struct  fpacc87 {
    #ifdef dontdef /* too unportable */
            u_long  fp_mantlo;      /* mantissa low (31:0) */
            u_long  fp_manthi;      /* mantissa high (63:32) */
            int     fp_exp:15;      /* exponent */
            int     fp_sgn:1;       /* mantissa sign */
    #else
            u_char  fp_bytes[10];
    #endif
    };
    
    /* Floating point context */
    struct  save87 {
            struct  env87 sv_env;   /* floating point control/status */
            struct  fpacc87 sv_ac[8];       /* accumulator contents, 0-7 */
            u_long  sv_ex_sw;       /* status word for last exception */
            /*
             * Bogus padding for emulators.  Emulators should use their own
             * struct and arrange to store into this struct (ending here)
             * before it is inspected for ptracing or for core dumps.  Some
             * emulators overwrite the whole struct.  We have no good way of
             * knowing how much padding to leave.  Leave just enough for the
             * GPL emulator's i387_union (176 bytes total).
             */
            u_char  sv_pad[64];     /* padding; used by emulators */
    };
    
    /*
     * The hardware default control for i387's and later coprocessors is
     * 0x37F, giving:
     *
     *      round to nearest
     *      64-bit precision
     *      all exceptions masked.
     *
     * We modify the affine mode bit and precision bits in this to give:
     *
     *      affine mode for 287's (if they work at all) (1 in bitfield 1<<12)
     *      53-bit precision (2 in bitfield 3<<8)
    *
    * 64-bit precision often gives bad results with high level languages
    * because it makes the results of calculations depend on whether
    * intermediate values are stored in memory or in FPU registers.
    */
   #define __INITIAL_NPXCW__       0x127F
   
   #ifdef KERNEL
   extern struct proc *npxproc;
   
   int     npxdna __P((void));
   void    npxexit __P((struct proc *p));
   void    npxinit __P((int control));
   void    npxsave __P((struct save87 *addr));
   #endif
   
   #endif /* !_MACHINE_NPX_H_ */

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