ieeefp.h

标准c库代码,可以应用于各个系统提供了大量的基本函数

#ifndef _IEEE_FP_H_
#define _IEEE_FP_H_

#include "_ansi.h"

#include <machine/ieeefp.h>

/* FIXME FIXME FIXME:
   Neither of __ieee_{float,double}_shape_tape seem to be used anywhere
   except in libm/test.  If that is the case, please delete these from here.
   If that is not the case, please insert documentation here describing why
   they're needed.  */

#ifdef __IEEE_BIG_ENDIAN

typedef union 
{
  double value;
  struct 
  {
    unsigned int sign : 1;
    unsigned int exponent: 11;
    unsigned int fraction0:4;
    unsigned int fraction1:16;
    unsigned int fraction2:16;
    unsigned int fraction3:16;
    
  } number;
  struct 
  {
    unsigned int sign : 1;
    unsigned int exponent: 11;
    unsigned int quiet:1;
    unsigned int function0:3;
    unsigned int function1:16;
    unsigned int function2:16;
    unsigned int function3:16;
  } nan;
  struct 
  {
    unsigned long msw;
    unsigned long lsw;
  } parts;
    long aslong[2];
} __ieee_double_shape_type;

#endif

#ifdef __IEEE_LITTLE_ENDIAN

typedef union 
{
  double value;
  struct 
  {
#ifdef __SMALL_BITFIELDS
    unsigned int fraction3:16;
    unsigned int fraction2:16;
    unsigned int fraction1:16;
    unsigned int fraction0: 4;
#else
    unsigned int fraction1:32;
    unsigned int fraction0:20;
#endif
    unsigned int exponent :11;
    unsigned int sign     : 1;
  } number;
  struct 
  {
#ifdef __SMALL_BITFIELDS
    unsigned int function3:16;
    unsigned int function2:16;
    unsigned int function1:16;
    unsigned int function0:3;
#else
    unsigned int function1:32;
    unsigned int function0:19;
#endif
    unsigned int quiet:1;
    unsigned int exponent: 11;
    unsigned int sign : 1;
  } nan;
  struct 
  {
    unsigned long lsw;
    unsigned long msw;
  } parts;

  long aslong[2];

} __ieee_double_shape_type;

#endif

#ifdef __IEEE_BIG_ENDIAN

typedef union
{
  float value;
  struct 
  {
    unsigned int sign : 1;
    unsigned int exponent: 8;
    unsigned int fraction0: 7;
    unsigned int fraction1: 16;
  } number;
  struct 
  {
    unsigned int sign:1;
    unsigned int exponent:8;
    unsigned int quiet:1;
    unsigned int function0:6;
    unsigned int function1:16;
  } nan;
  long p1;
  
} __ieee_float_shape_type;

#endif

#ifdef __IEEE_LITTLE_ENDIAN

typedef union
{
  float value;
  struct 
  {
    unsigned int fraction0: 7;
    unsigned int fraction1: 16;
    unsigned int exponent: 8;
    unsigned int sign : 1;
  } number;
  struct 
  {
    unsigned int function1:16;
    unsigned int function0:6;
    unsigned int quiet:1;
    unsigned int exponent:8;
    unsigned int sign:1;
  } nan;
  long p1;
  
} __ieee_float_shape_type;

#endif





/* FLOATING ROUNDING */

typedef int fp_rnd;
#define FP_RN 0 	/* Round to nearest 		*/
#define FP_RM 1		/* Round down 			*/
#define FP_RP 2		/* Round up 			*/
#define FP_RZ 3		/* Round to zero (trunate) 	*/

fp_rnd _EXFUN(fpgetround,(void));
fp_rnd _EXFUN(fpsetround, (fp_rnd));

/* EXCEPTIONS */

typedef int fp_except;
#define FP_X_INV 0x10	/* Invalid operation 		*/
#define FP_X_DX  0x80	/* Divide by zero		*/
#define FP_X_OFL 0x04	/* Overflow exception		*/
#define FP_X_UFL 0x02	/* Underflow exception		*/
#define FP_X_IMP 0x01	/* imprecise exception		*/

fp_except _EXFUN(fpgetmask,(void));
fp_except _EXFUN(fpsetmask,(fp_except));
fp_except _EXFUN(fpgetsticky,(void));
fp_except _EXFUN(fpsetsticky, (fp_except));

/* INTEGER ROUNDING */

typedef int fp_rdi;
#define FP_RDI_TOZ 0	/* Round to Zero 		*/
#define FP_RDI_RD  1	/* Follow float mode		*/

fp_rdi _EXFUN(fpgetroundtoi,(void));
fp_rdi _EXFUN(fpsetroundtoi,(fp_rdi));

int _EXFUN(isnan, (double));
int _EXFUN(isinf, (double));
int _EXFUN(finite, (double));



int _EXFUN(isnanf, (float));
int _EXFUN(isinff, (float));
int _EXFUN(finitef, (float));

#define __IEEE_DBL_EXPBIAS 1023
#define __IEEE_FLT_EXPBIAS 127

#define __IEEE_DBL_EXPLEN 11
#define __IEEE_FLT_EXPLEN 8


#define __IEEE_DBL_FRACLEN (64 - (__IEEE_DBL_EXPLEN + 1))
#define __IEEE_FLT_FRACLEN (32 - (__IEEE_FLT_EXPLEN + 1))

#define __IEEE_DBL_MAXPOWTWO	((double)(1L << 32 - 2) * (1L << (32-11) - 32 + 1))
#define __IEEE_FLT_MAXPOWTWO	((float)(1L << (32-8) - 1))

#define __IEEE_DBL_NAN_EXP 0x7ff
#define __IEEE_FLT_NAN_EXP 0xff


#define isnanf(x) (((*(long *)&(x) & 0x7f800000L)==0x7f800000L) && \
		   ((*(long *)&(x) & 0x007fffffL)!=0000000000L))

#define isinff(x) (((*(long *)&(x) & 0x7f800000L)==0x7f800000L) && \
		   ((*(long *)&(x) & 0x007fffffL)==0000000000L))

#define finitef(x) (((*(long *)&(x) & 0x7f800000L)!=0x7f800000L))

#ifdef _DOUBLE_IS_32BITS
#undef __IEEE_DBL_EXPBIAS
#define __IEEE_DBL_EXPBIAS __IEEE_FLT_EXPBIAS

#undef __IEEE_DBL_EXPLEN
#define __IEEE_DBL_EXPLEN __IEEE_FLT_EXPLEN

#undef __IEEE_DBL_FRACLEN
#define __IEEE_DBL_FRACLEN __IEEE_FLT_FRACLEN

#undef __IEEE_DBL_MAXPOWTWO
#define __IEEE_DBL_MAXPOWTWO __IEEE_FLT_MAXPOWTWO

#undef __IEEE_DBL_NAN_EXP
#define __IEEE_DBL_NAN_EXP __IEEE_FLT_NAN_EXP

#undef __ieee_double_shape_type
#define __ieee_double_shape_type __ieee_float_shape_type

#endif /* _DOUBLE_IS_32BITS */

#endif /* _IEEE_FP_H_ */