/*-
 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
 * Copyright (c) 2015-2016 Ruslan Bukin <br@bsdpad.com>
 * All rights reserved.
 *
 * Portions of this software were developed by SRI International and the
 * University of Cambridge Computer Laboratory under DARPA/AFRL contract
 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
 *
 * Portions of this software were developed by the University of Cambridge
 * Computer Laboratory as part of the CTSRD Project, with support from the
 * UK Higher Education Innovation Fund (HEIF).
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 _FENV_H_
#define _FENV_H_

#include <sys/cdefs.h>
#include <sys/_types.h>

#ifndef __fenv_static
#define __fenv_static   static
#endif

typedef __uint64_t      fenv_t;
typedef __uint64_t      fexcept_t;

/* Exception flags */
#define FE_INVALID      0x0010
#define FE_DIVBYZERO    0x0008
#define FE_OVERFLOW     0x0004
#define FE_UNDERFLOW    0x0002
#define FE_INEXACT      0x0001
#define FE_ALL_EXCEPT   (FE_DIVBYZERO | FE_INEXACT | \
                         FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)

/*
 * RISC-V Rounding modes
 */
#define _ROUND_SHIFT    5
#define FE_TONEAREST    (0x00 << _ROUND_SHIFT)
#define FE_TOWARDZERO   (0x01 << _ROUND_SHIFT)
#define FE_DOWNWARD     (0x02 << _ROUND_SHIFT)
#define FE_UPWARD       (0x03 << _ROUND_SHIFT)
#define _ROUND_MASK     (FE_TONEAREST | FE_DOWNWARD | \
                         FE_UPWARD | FE_TOWARDZERO)

__BEGIN_DECLS

/* Default floating-point environment */
extern const fenv_t     __fe_dfl_env;
#define FE_DFL_ENV      (&__fe_dfl_env)

#ifndef __riscv_float_abi_double
#error only double hard float ABI supported
#endif

#define __rfs(__fcsr)   __asm __volatile("csrr %0, fcsr" : "=r" (__fcsr))
#define __wfs(__fcsr)   __asm __volatile("csrw fcsr, %0" :: "r" (__fcsr))

int feclearexcept(int);
int fegetexceptflag(fexcept_t *, int);
int fesetexceptflag(const fexcept_t *, int);
int feraiseexcept(int);
int fetestexcept(int);
int fegetround(void);
int fesetround(int);
int fegetenv(fenv_t *);
int feholdexcept(fenv_t *);
int fesetenv(const fenv_t *);
int feupdateenv(const fenv_t *);

#define feclearexcept(a)        __feclearexcept_int(a)
#define fegetexceptflag(e, a)   __fegetexceptflag_int(e, a)
#define fesetexceptflag(e, a)   __fesetexceptflag_int(e, a)
#define feraiseexcept(a)        __feraiseexcept_int(a)
#define fetestexcept(a)         __fetestexcept_int(a)
#define fegetround()            __fegetround_int()
#define fesetround(a)           __fesetround_int(a)
#define fegetenv(e)             __fegetenv_int(e)
#define feholdexcept(e)         __feholdexcept_int(e)
#define fesetenv(e)             __fesetenv_int(e)
#define feupdateenv(e)          __feupdateenv_int(e)

__fenv_static inline int
__feclearexcept_int(int __excepts)
{

        __asm __volatile("csrc fflags, %0" :: "r"(__excepts));

        return (0);
}

__fenv_static inline int
__fegetexceptflag_int(fexcept_t *__flagp, int __excepts)
{
        fexcept_t __fcsr;

        __rfs(__fcsr);
        *__flagp = __fcsr & __excepts;

        return (0);
}

__fenv_static inline int
__fesetexceptflag_int(const fexcept_t *__flagp, int __excepts)
{
        fexcept_t __fcsr;

        __fcsr = *__flagp;
        __asm __volatile("csrc fflags, %0" :: "r"(__excepts));
        __asm __volatile("csrs fflags, %0" :: "r"(__fcsr & __excepts));

        return (0);
}

__fenv_static inline int
__feraiseexcept_int(int __excepts)
{

        __asm __volatile("csrs fflags, %0" :: "r"(__excepts));

        return (0);
}

__fenv_static inline int
__fetestexcept_int(int __excepts)
{
        fexcept_t __fcsr;

        __rfs(__fcsr);

        return (__fcsr & __excepts);
}

__fenv_static inline int
__fegetround_int(void)
{
        fexcept_t __fcsr;

        __rfs(__fcsr);

        return (__fcsr & _ROUND_MASK);
}

__fenv_static inline int
__fesetround_int(int __round)
{
        fexcept_t __fcsr;

        if (__round & ~_ROUND_MASK)
                return (-1);

        __rfs(__fcsr);
        __fcsr &= ~_ROUND_MASK;
        __fcsr |= __round;
        __wfs(__fcsr);

        return (0);
}

__fenv_static inline int
__fegetenv_int(fenv_t *__envp)
{

        __rfs(*__envp);

        return (0);
}

__fenv_static inline int
__feholdexcept_int(fenv_t *__envp __unused)
{

        /* No exception traps. */

        return (-1);
}

__fenv_static inline int
__fesetenv_int(const fenv_t *__envp)
{

        __wfs(*__envp);

        return (0);
}

__fenv_static inline int
__feupdateenv_int(const fenv_t *__envp)
{
        fexcept_t __fcsr;

        __rfs(__fcsr);
        __wfs(*__envp);
        feraiseexcept(__fcsr & FE_ALL_EXCEPT);

        return (0);
}

#if __BSD_VISIBLE

int feenableexcept(int);
int fedisableexcept(int);

#define feenableexcept(a)       __feenableexcept_int(a)
#define fedisableexcept(a)      __fedisableexcept_int(a)

__fenv_static inline int
__feenableexcept_int(int __mask __unused)
{

        /* No exception traps. */

        return (0);
}

__fenv_static inline int
__fedisableexcept_int(int __mask __unused)
{

        /* No exception traps. */

        return (0);
}

/* We currently provide no external definition of fegetexcept(). */
static inline int
fegetexcept(void)
{

        /* No exception traps. */

        return (0);
}

#endif /* __BSD_VISIBLE */

__END_DECLS

#endif  /* !_FENV_H_ */