usr/src/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.
 *
 * %sccs.include.noredist.c%
 *
 *      @(#)npx.h       5.1 (Berkeley) %G%
 */

/*
 * 287/387 Floating Point Data Structures and Constants
 * W. Jolitz 1/90
 */

#ifndef ___FPU87___
#define ___FPU87___

/* 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 {
        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 */
};

/* Floating point context */
struct  save87 {
        struct  env87 sv_env;           /* floating point control/status */
        struct  fpacc87 sv_ac[8];       /* accumulator contents, 0-7 */
};

#endif  ___FPU87___