text: /*-
   * 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: src/sys/amd64/include/ieeefp.h,v 1.11 2003/11/08 04:39:22 peter Exp $
   */
  
  /*
   *	IEEE floating point type and constant definitions.
   */
  
  #ifndef _MACHINE_IEEEFP_H_
  #define _MACHINE_IEEEFP_H_
  
  /*
   * FP rounding modes
   */
  typedef enum {
  	FP_RN=0,	/* round to nearest */
  	FP_RM,		/* round down to minus infinity */
  	FP_RP,		/* round up to plus infinity */
  	FP_RZ		/* truncate */
  } fp_rnd_t;
  
  /*
   * FP 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
  
  /*
   * FP exception 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 */
  
  /*
   * FP registers
   */
  #define FP_MSKS_REG	0	/* exception masks */
  #define FP_PRC_REG	0	/* precision */
  #define FP_RND_REG	0	/* direction */
  #define FP_STKY_REG	1	/* sticky flags */
  
  /*
   * FP register bit field masks
   */
  #define FP_MSKS_FLD	0x3f	/* exception masks field */
  #define FP_PRC_FLD	0x300	/* precision control field */
  #define FP_RND_FLD	0xc00	/* round control field */
  #define FP_STKY_FLD	0x3f	/* sticky flags field */
  
  /*
   * SSE mxcsr register bit field masks
   */
  #define	SSE_STKY_FLD	0x3f	/* exception flags */
  #define	SSE_DAZ_FLD	0x40	/* Denormals are zero */
  #define	SSE_MSKS_FLD	0x1f80	/* exception masks field */
  #define	SSE_RND_FLD	0x6000	/* rounding control */
  #define	SSE_FZ_FLD	0x8000	/* flush to zero on underflow */
  
  /*
   * FP register bit field offsets
   */
  #define FP_MSKS_OFF	0	/* exception masks offset */
  #define FP_PRC_OFF	8	/* precision control offset */
  #define FP_RND_OFF	10	/* round control offset */
  #define FP_STKY_OFF	0	/* sticky flags offset */
  
  /*
   * SSE mxcsr register bit field offsets
   */
  #define	SSE_STKY_OFF	0	/* exception flags offset */
  #define	SSE_DAZ_OFF	6	/* DAZ exception mask offset */
  #define	SSE_MSKS_OFF	7	/* other exception masks offset */
  #define	SSE_RND_OFF	13	/* rounding control offset */
  #define	SSE_FZ_OFF	15	/* flush to zero offset */
  
  #if defined(__GNUC__) && !defined(__cplusplus)
  
  #define	__fldenv(addr)	__asm __volatile("fldenv %0" : : "m" (*(addr)))
  #define	__fnstenv(addr)	__asm __volatile("fnstenv %0" : "=m" (*(addr)))
  #define	__fldcw(addr)	__asm __volatile("fldcw %0" : "=m" (*(addr)))
  #define	__fnstcw(addr)	__asm __volatile("fnstcw %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)))
  
  /*
   * General notes about conflicting SSE vs FP status bits.
   * This code assumes that software will not fiddle with the control
   * bits of the SSE and x87 in such a way to get them out of sync and
   * still expect this to work.  Break this at your peril.
   * Because I based this on the i386 port, the x87 state is used for
   * the fpget*() functions, and is shadowed into the SSE state for
   * the fpset*() functions.  For dual source fpget*() functions, I
   * merge the two together.  I think.
   */
  
  /* Set rounding control */
  static __inline__ fp_rnd_t
  __fpgetround(void)
  {
  	unsigned short _cw;
  
  	__fnstcw(&_cw);
  	return ((_cw & FP_RND_FLD) >> FP_RND_OFF);
  }
  
  static __inline__ fp_rnd_t
  __fpsetround(fp_rnd_t _m)
  {
  	unsigned short _cw;
  	unsigned int _mxcsr;
  	fp_rnd_t _p;
  
  	__fnstcw(&_cw);
  	_p = (_cw & FP_RND_FLD) >> FP_RND_OFF;
  	_cw &= ~FP_RND_FLD;
  	_cw |= (_m << FP_RND_OFF) & FP_RND_FLD;
  	__fldcw(&_cw);
  	__stmxcsr(&_mxcsr);
  	_mxcsr &= ~SSE_RND_FLD;
  	_mxcsr |= (_m << SSE_RND_OFF) & SSE_RND_FLD;
  	__ldmxcsr(&_mxcsr);
  	return (_p);
  }
  
  /*
   * Set precision for fadd/fsub/fsqrt etc x87 instructions
   * There is no equivalent SSE mode or control.
   */
  static __inline__ fp_prec_t
  __fpgetprec(void)
  {
  	unsigned short _cw;
  
  	__fnstcw(&_cw);
  	return ((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
  }
  
  static __inline__ fp_prec_t
  __fpsetprec(fp_rnd_t _m)
  {
  	unsigned short _cw;
  	fp_prec_t _p;
  
  	__fnstcw(&_cw);
  	_p = (_cw & FP_PRC_FLD) >> FP_PRC_OFF;
  	_cw &= ~FP_PRC_FLD;
  	_cw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
  	__fldcw(&_cw);
  	return (_p);
  }
  
  /*
   * Look at the exception masks
   * Note that x87 masks are inverse of the fp*() functions
   * API.  ie: mask = 1 means disable for x87 and SSE, but
   * for the fp*() api, mask = 1 means enabled.
   */
  static __inline__ fp_except_t
  __fpgetmask(void)
  {
  	unsigned short _cw;
  
  	__fnstcw(&_cw);
  	return ((~_cw) & FP_MSKS_FLD);
  }
  
  static __inline__ fp_except_t
  __fpsetmask(fp_except_t _m)
  {
  	unsigned short _cw;
  	unsigned int _mxcsr;
  	fp_except_t _p;
  
  	__fnstcw(&_cw);
  	_p = (~_cw) & FP_MSKS_FLD;
  	_cw &= ~FP_MSKS_FLD;
  	_cw |= (~_m) & FP_MSKS_FLD;
  	__fldcw(&_cw);
  	__stmxcsr(&_mxcsr);
  	/* XXX should we clear non-ieee SSE_DAZ_FLD and SSE_FZ_FLD ? */
  	_mxcsr &= ~SSE_MSKS_FLD;
  	_mxcsr |= ((~_m) << SSE_MSKS_OFF) & SSE_MSKS_FLD;
  	__ldmxcsr(&_mxcsr);
  	return (_p);
  }
  
  /* See which sticky exceptions are pending, and reset them */
  static __inline__ fp_except_t
  __fpgetsticky(void)
  {
  	unsigned short _sw;
  	unsigned int _mxcsr;
  	fp_except_t _ex;
  
  	__fnstsw(&_sw);
  	_ex = _sw & FP_STKY_FLD;
  	__stmxcsr(&_mxcsr);
  	_ex |= _mxcsr & SSE_STKY_FLD;
  	return (_ex);
  }
  
  /* Note that this should really be called fpresetsticky() */
  static __inline__ fp_except_t
  __fpsetsticky(fp_except_t _m)
  {
  	unsigned _env[7];
  	unsigned int _mxcsr;
  	fp_except_t _p;
  
  	__fnstenv(_env);
  	_p = _env[FP_STKY_REG] & _m;
  	__stmxcsr(&_mxcsr);
  	_p |= _mxcsr & SSE_STKY_FLD;
  	_env[FP_STKY_REG] &= ~_m;
  	__fldenv(_env);
  	_mxcsr &= ~_m;
  	__ldmxcsr(&_mxcsr);
  	return (_p);
  }
  
  #endif /* __GNUC__ && !__cplusplus */
  
  #if !defined(__IEEEFP_NOINLINES__) && !defined(__cplusplus) && defined(__GNUC__)
  
  #define	fpgetround()	__fpgetround()
  #define	fpsetround(_m)	__fpsetround(_m)
  #define	fpgetprec()	__fpgetprec()
  #define	fpsetprec(_m)	__fpsetprec(_m)
  #define	fpgetmask()	__fpgetmask()
  #define	fpsetmask(_m)	__fpsetmask(_m)
  #define	fpgetsticky()	__fpgetsticky()
  #define	fpsetsticky(_m)	__fpsetsticky(_m)
  
  /* Suppress prototypes in the MI header. */
  #define	_IEEEFP_INLINED_	1
  
  #else /* !__IEEEFP_NOINLINES__ && !__cplusplus && __GNUC__ */
  
  /* Augment the userland declarations */
  __BEGIN_DECLS
  extern fp_prec_t fpgetprec(void);
  extern fp_prec_t fpsetprec(fp_prec_t);
  __END_DECLS
  
  #endif /* !__IEEEFP_NOINLINES__ && !__cplusplus && __GNUC__ */
  
  #endif /* !_MACHINE_IEEEFP_H_ */
  