bsd_ieeefp.h

Go to the documentation of this file.

/*-
 * 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.
 *
 *  from: @(#) ieeefp.h     1.0 (Berkeley) 9/23/93
 * $FreeBSD$
 */
 
#ifndef _MACHINE_IEEEFP_H_
#define _MACHINE_IEEEFP_H_
 
/*
 * Deprecated historical FPU control interface
 *
 * IEEE floating point type, constant and function definitions.
 * XXX: FP*FLD and FP*OFF are undocumented pollution.
 */
 
/* VBS
 
#ifndef _SYS_CDEFS_H_
#error this file needs sys/cdefs.h as a prerequisite
#endif
 
*/
 
/*
 * 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 */
 
//VBS
//#ifdef __GNUCLIKE_ASM
 
#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)))
 
/*
 * 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);
}
 
static __inline fp_rnd_t
fpgetround(void)
{
    unsigned short _cw;
 
    __fnstcw(&_cw);
    return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));
}
 
static __inline fp_rnd_t
fpsetround(fp_rnd_t _m)
{
    fp_rnd_t _p;
    unsigned short _cw, _newcw;
 
    __fnstcw(&_cw);
    _p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF);
    _newcw = _cw & ~FP_RND_FLD;
    _newcw |= (_m << FP_RND_OFF) & FP_RND_FLD;
    __fnldcw(_cw, _newcw);
    return (_p);
}
 
//static __inline fp_prec_t
OLM_DLLEXPORT fp_prec_t
fpgetprec(void)
{
    unsigned short _cw;
 
    __fnstcw(&_cw);
    return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF));
}
 
//static __inline fp_prec_t
OLM_DLLEXPORT fp_prec_t
fpsetprec(fp_prec_t _m)
{
    fp_prec_t _p;
    unsigned short _cw, _newcw;
 
    __fnstcw(&_cw);
    _p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
    _newcw = _cw & ~FP_PRC_FLD;
    _newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
    __fnldcw(_cw, _newcw);
    return (_p);
}
 
/*
 * Get or set the exception mask.
 * Note that the x87 mask bits are inverted by the API -- a mask bit of 1
 * means disable for x87 and SSE, but for fp*mask() it means enable.
 */
 
static __inline fp_except_t
fpgetmask(void)
{
    unsigned short _cw;
 
    __fnstcw(&_cw);
    return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF);
}
 
static __inline fp_except_t
fpsetmask(fp_except_t _m)
{
    fp_except_t _p;
    unsigned short _cw, _newcw;
 
    __fnstcw(&_cw);
    _p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF;
    _newcw = _cw & ~FP_MSKS_FLD;
    _newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD;
    __fnldcw(_cw, _newcw);
    return (_p);
}
 
static __inline fp_except_t
fpgetsticky(void)
{
    unsigned _ex;
    unsigned short _sw;
 
    __fnstsw(&_sw);
    _ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF;
    return ((fp_except_t)_ex);
}
 
static __inline fp_except_t
fpresetsticky(fp_except_t _m)
{
    struct {
        unsigned _cw;
        unsigned _sw;
        unsigned _other[5];
    } _env;
    fp_except_t _p;
 
    _m &= FP_STKY_FLD >> FP_STKY_OFF;
    _p = fpgetsticky();
    if ((_p & ~_m) == _p)
        return (_p);
    if ((_p & ~_m) == 0) {
        __fnclex();
        return (_p);
    }
    __fnstenv(&_env);
    _env._sw &= ~_m;
    __fldenv(&_env);
    return (_p);
}
 
//#endif /* __GNUCLIKE_ASM */
 
#endif /* !_MACHINE_IEEEFP_H_ */