/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 2003 Peter Wemm.
 * Copyright (c) 1990 Andrew Moore, Talke Studio
 * All rights reserved.
 *
 * 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.
 */

#ifndef _X86_X86_IEEEFP_H_
#define _X86_X86_IEEEFP_H_

/* Deprecated historical FPU control interface */

/*
 * IEEE floating point type, constant and function definitions.
 * XXX: {FP,SSE}*FLD and {FP,SSE}*OFF are undocumented pollution.
 */

/*
 * Rounding modes.
 */
typedef enum {
        FP_RN=0,        /* round to nearest */
        FP_RM,          /* round down towards minus infinity */
        FP_RP,          /* round up towards plus infinity */
        FP_RZ           /* truncate */
} fp_rnd_t;

/*
 * Precision (i.e., rounding precision) modes.
 */
typedef enum {
        FP_PS=0,        /* 24 bit (single-precision) */
        FP_PRS,         /* reserved */
        FP_PD,          /* 53 bit (double-precision) */
        FP_PE           /* 64 bit (extended-precision) */
} fp_prec_t;

#define fp_except_t     int

/*
 * Exception bit masks.
 */
#define FP_X_INV        0x01    /* invalid operation */
#define FP_X_DNML       0x02    /* denormal */
#define FP_X_DZ         0x04    /* zero divide */
#define FP_X_OFL        0x08    /* overflow */
#define FP_X_UFL        0x10    /* underflow */
#define FP_X_IMP        0x20    /* (im)precision */
#define FP_X_STK        0x40    /* stack fault */

/*
 * FPU control word bit-field masks.
 */
#define FP_MSKS_FLD     0x3f    /* exception masks field */
#define FP_PRC_FLD      0x300   /* precision control field */
#define FP_RND_FLD      0xc00   /* rounding control field */

/*
 * FPU status word bit-field masks.
 */
#define FP_STKY_FLD     0x3f    /* sticky flags field */

/*
 * FPU control word bit-field offsets (shift counts).
 */
#define FP_MSKS_OFF     0       /* exception masks offset */
#define FP_PRC_OFF      8       /* precision control offset */
#define FP_RND_OFF      10      /* rounding control offset */

/*
 * FPU status word bit-field offsets (shift counts).
 */
#define FP_STKY_OFF     0       /* sticky flags offset */

#define __fldcw(addr)   __asm __volatile("fldcw %0" : : "m" (*(addr)))
#define __fldenv(addr)  __asm __volatile("fldenv %0" : : "m" (*(addr)))
#define __fnclex()      __asm __volatile("fnclex")
#define __fnstcw(addr)  __asm __volatile("fnstcw %0" : "=m" (*(addr)))
#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
#define __fnstsw(addr)  __asm __volatile("fnstsw %0" : "=m" (*(addr)))
#define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : : "m" (*(addr)))
#define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr)))

/*
 * Load the control word.  Be careful not to trap if there is a currently
 * unmasked exception (ones that will become freshly unmasked are not a
 * problem).  This case must be handled by a save/restore of the
 * environment or even of the full x87 state.  Accessing the environment
 * is very inefficient, so only do it when necessary.
 */
static __inline void
__fnldcw(unsigned short _cw, unsigned short _newcw)
{
        struct {
                unsigned _cw;
                unsigned _other[6];
        } _env;
        unsigned short _sw;

        if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) {
                __fnstsw(&_sw);
                if (((_sw & ~_cw) & FP_STKY_FLD) != 0) {
                        __fnstenv(&_env);
                        _env._cw = _newcw;
                        __fldenv(&_env);
                        return;
                }
        }
        __fldcw(&_newcw);
}

#endif/* _X86_X86_IEEEFP_H_ */