FreeBSD/Linux Kernel Cross Reference
sys/x86/include/fpu.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.
     * 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: releng/10.2/sys/x86/include/fpu.h 279211 2015-02-23 18:38:41Z jhb $
     */
    
    /*
     * Floating Point Data Structures and Constants
     * W. Jolitz 1/90
     */
    
    #ifndef _X86_FPU_H_
    #define _X86_FPU_H_
    
    /* Environment information of floating point unit. */
    struct env87 {
            int32_t         en_cw;          /* control word (16bits) */
            int32_t         en_sw;          /* status word (16bits) */
            int32_t         en_tw;          /* tag word (16bits) */
            int32_t         en_fip;         /* fp instruction pointer */
            uint16_t        en_fcs;         /* fp code segment selector */
            uint16_t        en_opcode;      /* opcode last executed (11 bits) */
            int32_t         en_foo;         /* fp operand offset */
            int32_t         en_fos;         /* fp operand segment selector */
    };
    
    /* Contents of each x87 floating point accumulator. */
    struct fpacc87 {
            uint8_t         fp_bytes[10];
    };
    
    /* Floating point context. (i386 fnsave/frstor) */
    struct save87 {
            struct env87    sv_env;         /* floating point control/status */
            struct fpacc87  sv_ac[8];       /* accumulator contents, 0-7 */
            uint8_t         sv_pad0[4];     /* saved status word (now unused) */
            uint8_t         sv_pad[64];
    };
    
    /* Contents of each SSE extended accumulator. */
    struct xmmacc {
            uint8_t         xmm_bytes[16];
    };
    
    /* Contents of the upper 16 bytes of each AVX extended accumulator. */
    struct ymmacc {
            uint8_t         ymm_bytes[16];
    };
    
    /* Rename structs below depending on machine architecture. */
    #ifdef __i386__
    #define __envxmm32      envxmm
    #else
    #define __envxmm32      envxmm32
    #define __envxmm64      envxmm
    #endif
    
    struct __envxmm32 {
            uint16_t        en_cw;          /* control word (16bits) */
            uint16_t        en_sw;          /* status word (16bits) */
            uint16_t        en_tw;          /* tag word (16bits) */
            uint16_t        en_opcode;      /* opcode last executed (11 bits) */
            uint32_t        en_fip;         /* fp instruction pointer */
            uint16_t        en_fcs;         /* fp code segment selector */
            uint16_t        en_pad0;        /* padding */
            uint32_t        en_foo;         /* fp operand offset */
            uint16_t        en_fos;         /* fp operand segment selector */
            uint16_t        en_pad1;        /* padding */
            uint32_t        en_mxcsr;       /* SSE control/status register */
            uint32_t        en_mxcsr_mask;  /* valid bits in mxcsr */
   };
   
   struct __envxmm64 {
           uint16_t        en_cw;          /* control word (16bits) */
           uint16_t        en_sw;          /* status word (16bits) */
           uint8_t         en_tw;          /* tag word (8bits) */
           uint8_t         en_zero;
           uint16_t        en_opcode;      /* opcode last executed (11 bits ) */
           uint64_t        en_rip;         /* fp instruction pointer */
           uint64_t        en_rdp;         /* fp operand pointer */
           uint32_t        en_mxcsr;       /* SSE control/status register */
           uint32_t        en_mxcsr_mask;  /* valid bits in mxcsr */
   };
   
   /* Floating point context. (i386 fxsave/fxrstor) */
   struct savexmm {
           struct __envxmm32       sv_env;
           struct {
                   struct fpacc87  fp_acc;
                   uint8_t         fp_pad[6];      /* padding */
           } sv_fp[8];
           struct xmmacc           sv_xmm[8];
           uint8_t                 sv_pad[224];
   } __aligned(16);
   
   #ifdef __i386__
   union savefpu {
           struct save87   sv_87;
           struct savexmm  sv_xmm;
   };
   #else
   /* Floating point context. (amd64 fxsave/fxrstor) */
   struct savefpu {
           struct __envxmm64       sv_env;
           struct {
                   struct fpacc87  fp_acc;
                   uint8_t         fp_pad[6];      /* padding */
           } sv_fp[8];
           struct xmmacc           sv_xmm[16];
           uint8_t                 sv_pad[96];
   } __aligned(16);
   #endif
   
   struct xstate_hdr {
           uint64_t        xstate_bv;
           uint64_t        xstate_xcomp_bv;
           uint8_t         xstate_rsrv0[8];
           uint8_t         xstate_rsrv[40];
   };
   #define XSTATE_XCOMP_BV_COMPACT (1ULL << 63)
   
   struct savexmm_xstate {
           struct xstate_hdr       sx_hd;
           struct ymmacc           sx_ymm[16];
   };
   
   struct savexmm_ymm {
           struct __envxmm32       sv_env;
           struct {
                   struct fpacc87  fp_acc;
                   int8_t          fp_pad[6];      /* padding */
           } sv_fp[8];
           struct xmmacc           sv_xmm[16];
           uint8_t                 sv_pad[96];
           struct savexmm_xstate   sv_xstate;
   } __aligned(64);
   
   struct savefpu_xstate {
           struct xstate_hdr       sx_hd;
           struct ymmacc           sx_ymm[16];
   };
   
   struct savefpu_ymm {
           struct __envxmm64       sv_env;
           struct {
                   struct fpacc87  fp_acc;
                   int8_t          fp_pad[6];      /* padding */
           } sv_fp[8];
           struct xmmacc           sv_xmm[16];
           uint8_t                 sv_pad[96];
           struct savefpu_xstate   sv_xstate;
   } __aligned(64);
   
   #undef __envxmm32
   #undef __envxmm64
   
   /*
    * The hardware default control word for i387's and later coprocessors is
    * 0x37F, giving:
    *
    *      round to nearest
    *      64-bit precision
    *      all exceptions masked.
    *
    * FreeBSD/i386 uses 53 bit precision for things like fadd/fsub/fsqrt etc
    * because of the difference between memory and fpu register stack arguments.
    * If its using an intermediate fpu register, it has 80/64 bits to work
    * with.  If it uses memory, it has 64/53 bits to work with.  However,
    * gcc is aware of this and goes to a fair bit of trouble to make the
    * best use of it.
    *
    * This is mostly academic for AMD64, because the ABI prefers the use
    * SSE2 based math.  For FreeBSD/amd64, we go with the default settings.
    */
   #define __INITIAL_FPUCW__       0x037F
   #define __INITIAL_FPUCW_I386__  0x127F
   #define __INITIAL_NPXCW__       __INITIAL_FPUCW_I386__
   #define __INITIAL_MXCSR__       0x1F80
   #define __INITIAL_MXCSR_MASK__  0xFFBF
   
   /*
    * The current value of %xcr0 is saved in the sv_pad[] field of the FPU
    * state in the NT_X86_XSTATE note in core dumps.  This offset is chosen
    * to match the offset used by NT_X86_XSTATE in other systems.
    */
   #define X86_XSTATE_XCR0_OFFSET  464
   
   #endif /* !_X86_FPU_H_ */

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