sys/arch/i386/include/npx.h

   1 /*      $NetBSD: npx.h,v 1.22 2006/05/02 19:03:24 drochner Exp $        */
   2
   3 /*-
   4  * Copyright (c) 1990 The Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * William Jolitz.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)npx.h       5.3 (Berkeley) 1/18/91
  35  */
  36
  37 /*
  38  * 287/387 NPX Coprocessor Data Structures and Constants
  39  * W. Jolitz 1/90
  40  */
  41
  42 #ifndef _I386_NPX_H_
  43 #define _I386_NPX_H_
  44
  45 /* Environment information of floating point unit */
  46 struct env87 {
  47         long    en_cw;          /* control word (16bits) */
  48         long    en_sw;          /* status word (16bits) */
  49         long    en_tw;          /* tag word (16bits) */
  50         long    en_fip;         /* floating point instruction pointer */
  51         u_short en_fcs;         /* floating code segment selector */
  52         u_short en_opcode;      /* opcode last executed (11 bits ) */
  53         long    en_foo;         /* floating operand offset */
  54         long    en_fos;         /* floating operand segment selector */
  55 };
  56
  57 /* Contents of each floating point accumulator */
  58 struct fpacc87 {
  59 #ifdef dontdef  /* too unportable */
  60         u_long  fp_mantlo;      /* mantissa low (31:0) */
  61         u_long  fp_manthi;      /* mantissa high (63:32) */
  62         int     fp_exp:15;      /* exponent */
  63         int     fp_sgn:1;       /* mantissa sign */
  64 #else
  65         u_char  fp_bytes[10];
  66 #endif
  67 };
  68
  69 /* Floating point context */
  70 struct save87 {
  71         struct  env87 sv_env;           /* floating point control/status */
  72         struct  fpacc87 sv_ac[8];       /* accumulator contents, 0-7 */
  73 #ifndef dontdef
  74         u_long  sv_ex_sw;       /* status word for last exception (was pad) */
  75         u_long  sv_ex_tw;       /* tag word for last exception (was pad) */
  76         u_char  sv_pad[8 * 2 - 2 * 4];  /* bogus historical padding */
  77 #endif
  78 };
  79
  80 /* Environment of FPU/MMX/SSE/SSE2. */
  81 struct envxmm {
  82 /*0*/   uint16_t en_cw;         /* FPU Control Word */
  83         uint16_t en_sw;         /* FPU Status Word */
  84         uint8_t  en_tw;         /* FPU Tag Word (abridged) */
  85         uint8_t  en_rsvd0;
  86         uint16_t en_opcode;     /* FPU Opcode */
  87         uint32_t en_fip;        /* FPU Instruction Pointer */
  88         uint16_t en_fcs;        /* FPU IP selector */
  89         uint16_t en_rsvd1;
  90 /*16*/  uint32_t en_foo;        /* FPU Data pointer */
  91         uint16_t en_fos;        /* FPU Data pointer selector */
  92         uint16_t en_rsvd2;
  93         uint32_t en_mxcsr;      /* MXCSR Register State */
  94         uint32_t en_rsvd3;
  95 };
  96
  97 /* FPU regsters in the extended save format. */
  98 struct fpaccxmm {
  99         uint8_t fp_bytes[10];
 100         uint8_t fp_rsvd[6];
 101 };
 102
 103 /* SSE/SSE2 registers. */
 104 struct xmmreg {
 105         uint8_t sse_bytes[16];
 106 };
 107
 108 /* FPU/MMX/SSE/SSE2 context */
 109 struct savexmm {
 110         struct envxmm sv_env;           /* control/status context */
 111         struct fpaccxmm sv_ac[8];       /* ST/MM regs */
 112         struct xmmreg sv_xmmregs[8];    /* XMM regs */
 113         uint8_t sv_rsvd[16 * 14];
 114         /* 512-bytes --- end of hardware portion of save area */
 115         uint32_t sv_ex_sw;              /* saved SW from last exception */
 116         uint32_t sv_ex_tw;              /* saved TW from last exception */
 117 } __aligned(16);
 118
 119 union savefpu {
 120         struct save87 sv_87;
 121         struct savexmm sv_xmm;
 122 };
 123
 124 /*
 125  * The i387 defaults to Intel extended precision mode and round to nearest,
 126  * with all exceptions masked.
 127  */
 128 #define __INITIAL_NPXCW__       0x037f
 129 /* NetBSD uses IEEE double precision. */
 130 #define __NetBSD_NPXCW__        0x127f
 131 /* FreeBSD leaves some exceptions unmasked as well. */
 132 #define __FreeBSD_NPXCW__       0x1272
 133 /* iBCS2 goes a bit further and leaves the underflow exception unmasked. */
 134 #define __iBCS2_NPXCW__         0x0262
 135 /* Linux just uses the default control word. */
 136 #define __Linux_NPXCW__         0x037f
 137 /* SVR4 uses the same control word as iBCS2. */
 138 #define __SVR4_NPXCW__          0x0262
 139
 140 /*
 141  * The default MXCSR value at reset is 0x1f80, IA-32 Instruction
 142  * Set Reference, pg. 3-369.
 143  */
 144 #define __INITIAL_MXCSR__       0x1f80
 145
 146
 147 /*
 148  * 80387 control word bits
 149  */
 150 #define EN_SW_INVOP     0x0001  /* Invalid operation */
 151 #define EN_SW_DENORM    0x0002  /* Denormalized operand */
 152 #define EN_SW_ZERODIV   0x0004  /* Divide by zero */
 153 #define EN_SW_OVERFLOW  0x0008  /* Overflow */
 154 #define EN_SW_UNDERFLOW 0x0010  /* Underflow */
 155 #define EN_SW_PRECLOSS  0x0020  /* Loss of precision */
 156 #define EN_SW_DATACHAIN 0x0080  /* Data chain exception */
 157 #define EN_SW_CTL_PREC  0x0300  /* Precision control */
 158 #define EN_SW_CTL_ROUND 0x0c00  /* Rounding control */
 159 #define EN_SW_CTL_INF   0x1000  /* Infinity control */
 160
 161 /*
 162  * The standard control word from finit is 0x37F, giving:
 163  *      round to nearest
 164  *      64-bit precision
 165  *      all exceptions masked.
 166  *
 167  * Now we want:
 168  *      affine mode (if we decide to support 287's)
 169  *      round to nearest
 170  *      53-bit precision
 171  *      all exceptions masked.
 172  *
 173  * 64-bit precision often gives bad results with high level languages
 174  * because it makes the results of calculations depend on whether
 175  * intermediate values are stored in memory or in FPU registers.
 176  *
 177  * The iBCS control word has underflow, overflow, zero divide, and invalid
 178  * operation exceptions unmasked.  But that causes an unexpected exception
 179  * in the test program 'paranoia' and makes denormals useless (DBL_MIN / 2
 180  * underflows).  It doesn't make a lot of sense to trap underflow without
 181  * trapping denormals.
 182  */
 183
 184 #ifdef _KERNEL
 185
 186 void    probeintr(void);
 187 void    probetrap(void);
 188 int     npx586bug1(int, int);
 189 void    npxinit(struct cpu_info *);
 190 void    process_xmm_to_s87(const struct savexmm *, struct save87 *);
 191 void    process_s87_to_xmm(const struct save87 *, struct savexmm *);
 192
 193 #endif
 194
 195 #endif /* !_I386_NPX_H_ */