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newlib-cygwin/newlib/libc/stdlib/mprec.h
Hans-Peter Nilsson 5592f939b4 Fix strict-aliasing issues with _strtod_r and Storeinc. 
* libc/stdlib/strtod.c (_strtod_r): Change local variables aadj,
	rv, rv0 from double to type U.  Use accessor macros dval, dword0
	and dword1 for all accesses except for the ULtod call, where rv.i
	replaces the pointer cast.
	* libc/stdlib/mprec.h (U): Rename member L to i for easier re-use
	of access macros.  Tweak comment.
	Remove #ifdef'd YES_ALIAS code.
	(dword0, dword1, dval): Define in terms of uncast union member
	access.  Ditto for _DOUBLE_IS_32BITS variants.
	(Storeinc): Replace aliasing-flawed microoptimized definition with
	alternative suggested in comment.  Remove now stale comment.
2008-06-25 01:45:02 +00:00

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/****************************************************************
*
* The author of this software is David M. Gay.
*
* Copyright (c) 1991 by AT&T.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose without fee is hereby granted, provided that this entire notice
* is included in all copies of any software which is or includes a copy
* or modification of this software and in all copies of the supporting
* documentation for such software.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
* OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
*
***************************************************************/
/* Please send bug reports to
David M. Gay
AT&T Bell Laboratories, Room 2C-463
600 Mountain Avenue
Murray Hill, NJ 07974-2070
U.S.A.
dmg@research.att.com or research!dmg
*/
#include <ieeefp.h>
#include <math.h>
#include <float.h>
#include <errno.h>
#include <sys/config.h>
#include <sys/types.h>
#ifdef __IEEE_LITTLE_ENDIAN
#define IEEE_8087
#endif
#ifdef __IEEE_BIG_ENDIAN
#define IEEE_MC68k
#endif
#ifdef __Z8000__
#define Just_16
#endif
#ifdef DEBUG
#include "stdio.h"
#define Bug(x) {fprintf(stderr, "%s\n", x); exit(1);}
#endif
#ifdef Unsigned_Shifts
#define Sign_Extend(a,b) if (b < 0) a |= (__uint32_t)0xffff0000;
#else
#define Sign_Extend(a,b) /*no-op*/
#endif
#if defined(IEEE_8087) + defined(IEEE_MC68k) + defined(VAX) + defined(IBM) != 1
Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.
#endif
/* If we are going to examine or modify specific bits in a double using
the word0 and/or word1 macros, then we must wrap the double inside
a union. This is necessary to avoid undefined behavior according to
the ANSI C spec. */
union double_union
{
double d;
__uint32_t i[2];
};
#ifdef IEEE_8087
#define word0(x) (x.i[1])
#define word1(x) (x.i[0])
#else
#define word0(x) (x.i[0])
#define word1(x) (x.i[1])
#endif
/* The following is taken from gdtoaimp.h for use with new strtod, but
adjusted to avoid invalid type-punning. */
typedef __int32_t Long;
/* Unfortunately, because __ULong might be a different type than
__uint32_t, we can't re-use union double_union as-is without
further edits in strtod.c. */
typedef union { double d; __ULong i[2]; } U;
#define dword0(x) word0(x)
#define dword1(x) word1(x)
#define dval(x) (x.d)
#undef SI
#ifdef Sudden_Underflow
#define SI 1
#else
#define SI 0
#endif
#define Storeinc(a,b,c) (*(a)++ = (b) << 16 | (c) & 0xffff)
/* #define P DBL_MANT_DIG */
/* Ten_pmax = floor(P*log(2)/log(5)) */
/* Bletch = (highest power of 2 < DBL_MAX_10_EXP) / 16 */
/* Quick_max = floor((P-1)*log(FLT_RADIX)/log(10) - 1) */
/* Int_max = floor(P*log(FLT_RADIX)/log(10) - 1) */
#if defined(IEEE_8087) + defined(IEEE_MC68k)
#if defined (_DOUBLE_IS_32BITS)
#define Exp_shift 23
#define Exp_shift1 23
#define Exp_msk1 ((__uint32_t)0x00800000L)
#define Exp_msk11 ((__uint32_t)0x00800000L)
#define Exp_mask ((__uint32_t)0x7f800000L)
#define P 24
#define Bias 127
#define NO_HEX_FP /* not supported in this case */
#define IEEE_Arith
#define Emin (-126)
#define Exp_1 ((__uint32_t)0x3f800000L)
#define Exp_11 ((__uint32_t)0x3f800000L)
#define Ebits 8
#define Frac_mask ((__uint32_t)0x007fffffL)
#define Frac_mask1 ((__uint32_t)0x007fffffL)
#define Ten_pmax 10
#define Sign_bit ((__uint32_t)0x80000000L)
#define Ten_pmax 10
#define Bletch 2
#define Bndry_mask ((__uint32_t)0x007fffffL)
#define Bndry_mask1 ((__uint32_t)0x007fffffL)
#define LSB 1
#define Sign_bit ((__uint32_t)0x80000000L)
#define Log2P 1
#define Tiny0 0
#define Tiny1 1
#define Quick_max 5
#define Int_max 6
#define Infinite(x) (word0(x) == ((__uint32_t)0x7f800000L))
#undef word0
#undef word1
#undef dword0
#undef dword1
#define word0(x) (x.i[0])
#define word1(x) 0
#define dword0(x) word0(x)
#define dword1(x) 0
#else
#define Exp_shift 20
#define Exp_shift1 20
#define Exp_msk1 ((__uint32_t)0x100000L)
#define Exp_msk11 ((__uint32_t)0x100000L)
#define Exp_mask ((__uint32_t)0x7ff00000L)
#define P 53
#define Bias 1023
#define IEEE_Arith
#define Emin (-1022)
#define Exp_1 ((__uint32_t)0x3ff00000L)
#define Exp_11 ((__uint32_t)0x3ff00000L)
#define Ebits 11
#define Frac_mask ((__uint32_t)0xfffffL)
#define Frac_mask1 ((__uint32_t)0xfffffL)
#define Ten_pmax 22
#define Bletch 0x10
#define Bndry_mask ((__uint32_t)0xfffffL)
#define Bndry_mask1 ((__uint32_t)0xfffffL)
#define LSB 1
#define Sign_bit ((__uint32_t)0x80000000L)
#define Log2P 1
#define Tiny0 0
#define Tiny1 1
#define Quick_max 14
#define Int_max 14
#define Infinite(x) (word0(x) == ((__uint32_t)0x7ff00000L)) /* sufficient test for here */
#endif /* !_DOUBLE_IS_32BITS */
#ifndef Flt_Rounds
#ifdef FLT_ROUNDS
#define Flt_Rounds FLT_ROUNDS
#else
#define Flt_Rounds 1
#endif
#endif /*Flt_Rounds*/
#else /* !IEEE_8087 && !IEEE_MC68k */
#undef Sudden_Underflow
#define Sudden_Underflow
#ifdef IBM
#define Flt_Rounds 0
#define Exp_shift 24
#define Exp_shift1 24
#define Exp_msk1 ((__uint32_t)0x1000000L)
#define Exp_msk11 ((__uint32_t)0x1000000L)
#define Exp_mask ((__uint32_t)0x7f000000L)
#define P 14
#define Bias 65
#define Exp_1 ((__uint32_t)0x41000000L)
#define Exp_11 ((__uint32_t)0x41000000L)
#define Ebits 8 /* exponent has 7 bits, but 8 is the right value in b2d */
#define Frac_mask ((__uint32_t)0xffffffL)
#define Frac_mask1 ((__uint32_t)0xffffffL)
#define Bletch 4
#define Ten_pmax 22
#define Bndry_mask ((__uint32_t)0xefffffL)
#define Bndry_mask1 ((__uint32_t)0xffffffL)
#define LSB 1
#define Sign_bit ((__uint32_t)0x80000000L)
#define Log2P 4
#define Tiny0 ((__uint32_t)0x100000L)
#define Tiny1 0
#define Quick_max 14
#define Int_max 15
#else /* VAX */
#define Flt_Rounds 1
#define Exp_shift 23
#define Exp_shift1 7
#define Exp_msk1 0x80
#define Exp_msk11 ((__uint32_t)0x800000L)
#define Exp_mask ((__uint32_t)0x7f80L)
#define P 56
#define Bias 129
#define Exp_1 ((__uint32_t)0x40800000L)
#define Exp_11 ((__uint32_t)0x4080L)
#define Ebits 8
#define Frac_mask ((__uint32_t)0x7fffffL)
#define Frac_mask1 ((__uint32_t)0xffff007fL)
#define Ten_pmax 24
#define Bletch 2
#define Bndry_mask ((__uint32_t)0xffff007fL)
#define Bndry_mask1 ((__uint32_t)0xffff007fL)
#define LSB ((__uint32_t)0x10000L)
#define Sign_bit ((__uint32_t)0x8000L)
#define Log2P 1
#define Tiny0 0x80
#define Tiny1 0
#define Quick_max 15
#define Int_max 15
#endif
#endif
#ifndef IEEE_Arith
#define ROUND_BIASED
#else
#define Scale_Bit 0x10
#if defined(_DOUBLE_IS_32BITS) && defined(__v800)
#define n_bigtens 2
#else
#define n_bigtens 5
#endif
#endif
#ifdef IBM
#define n_bigtens 3
#endif
#ifdef VAX
#define n_bigtens 2
#endif
#ifndef __NO_INFNAN_CHECK
#define INFNAN_CHECK
#endif
/*
* NAN_WORD0 and NAN_WORD1 are only referenced in strtod.c. Prior to
* 20050115, they used to be hard-wired here (to 0x7ff80000 and 0,
* respectively), but now are determined by compiling and running
* qnan.c to generate gd_qnan.h, which specifies d_QNAN0 and d_QNAN1.
* Formerly gdtoaimp.h recommended supplying suitable -DNAN_WORD0=...
* and -DNAN_WORD1=... values if necessary. This should still work.
* (On HP Series 700/800 machines, -DNAN_WORD0=0x7ff40000 works.)
*/
#ifdef IEEE_Arith
#ifdef IEEE_MC68k
#define _0 0
#define _1 1
#ifndef NAN_WORD0
#define NAN_WORD0 d_QNAN0
#endif
#ifndef NAN_WORD1
#define NAN_WORD1 d_QNAN1
#endif
#else
#define _0 1
#define _1 0
#ifndef NAN_WORD0
#define NAN_WORD0 d_QNAN1
#endif
#ifndef NAN_WORD1
#define NAN_WORD1 d_QNAN0
#endif
#endif
#else
#undef INFNAN_CHECK
#endif
#ifdef RND_PRODQUOT
#define rounded_product(a,b) a = rnd_prod(a, b)
#define rounded_quotient(a,b) a = rnd_quot(a, b)
#ifdef KR_headers
extern double rnd_prod(), rnd_quot();
#else
extern double rnd_prod(double, double), rnd_quot(double, double);
#endif
#else
#define rounded_product(a,b) a *= b
#define rounded_quotient(a,b) a /= b
#endif
#define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1))
#define Big1 ((__uint32_t)0xffffffffL)
#ifndef Just_16
/* When Pack_32 is not defined, we store 16 bits per 32-bit long.
* This makes some inner loops simpler and sometimes saves work
* during multiplications, but it often seems to make things slightly
* slower. Hence the default is now to store 32 bits per long.
*/
#ifndef Pack_32
#define Pack_32
#endif
#else /* Just_16 */
#ifndef Pack_16
#define Pack_16
#endif
#endif /* Just_16 */
#ifdef Pack_32
#define ULbits 32
#define kshift 5
#define kmask 31
#define ALL_ON 0xffffffff
#else
#define ULbits 16
#define kshift 4
#define kmask 15
#define ALL_ON 0xffff
#endif
#ifdef __cplusplus
extern "C" double strtod(const char *s00, char **se);
extern "C" char *dtoa(double d, int mode, int ndigits,
int *decpt, int *sign, char **rve);
#endif
typedef struct _Bigint _Bigint;
#define Balloc _Balloc
#define Bfree _Bfree
#define multadd __multadd
#define s2b __s2b
#define lo0bits __lo0bits
#define hi0bits __hi0bits
#define i2b __i2b
#define mult __multiply
#define pow5mult __pow5mult
#define lshift __lshift
#define cmp __mcmp
#define diff __mdiff
#define ulp __ulp
#define b2d __b2d
#define d2b __d2b
#define ratio __ratio
#define any_on __any_on
#define gethex __gethex
#define copybits __copybits
#define hexnan __hexnan
#define hexdig_init __hexdig_init
#define hexdig __hexdig
#define tens __mprec_tens
#define bigtens __mprec_bigtens
#define tinytens __mprec_tinytens
struct _reent ;
struct FPI;
double _EXFUN(ulp,(double x));
double _EXFUN(b2d,(_Bigint *a , int *e));
_Bigint * _EXFUN(Balloc,(struct _reent *p, int k));
void _EXFUN(Bfree,(struct _reent *p, _Bigint *v));
_Bigint * _EXFUN(multadd,(struct _reent *p, _Bigint *, int, int));
_Bigint * _EXFUN(s2b,(struct _reent *, const char*, int, int, __ULong));
_Bigint * _EXFUN(i2b,(struct _reent *,int));
_Bigint * _EXFUN(mult, (struct _reent *, _Bigint *, _Bigint *));
_Bigint * _EXFUN(pow5mult, (struct _reent *, _Bigint *, int k));
int _EXFUN(hi0bits,(__ULong));
int _EXFUN(lo0bits,(__ULong *));
_Bigint * _EXFUN(d2b,(struct _reent *p, double d, int *e, int *bits));
_Bigint * _EXFUN(lshift,(struct _reent *p, _Bigint *b, int k));
_Bigint * _EXFUN(diff,(struct _reent *p, _Bigint *a, _Bigint *b));
int _EXFUN(cmp,(_Bigint *a, _Bigint *b));
int _EXFUN(gethex,(struct _reent *p, _CONST char **sp, struct FPI *fpi, Long *exp, _Bigint **bp, int sign));
double _EXFUN(ratio,(_Bigint *a, _Bigint *b));
__ULong _EXFUN(any_on,(_Bigint *b, int k));
void _EXFUN(copybits,(__ULong *c, int n, _Bigint *b));
void _EXFUN(hexdig_init,(void));
#ifdef INFNAN_CHECK
int _EXFUN(hexnan,(_CONST char **sp, struct FPI *fpi, __ULong *x0));
#endif
#define Bcopy(x,y) memcpy((char *)&x->_sign, (char *)&y->_sign, y->_wds*sizeof(__Long) + 2*sizeof(int))
extern _CONST double tinytens[];
extern _CONST double bigtens[];
extern _CONST double tens[];
extern unsigned char hexdig[];
double _EXFUN(_mprec_log10,(int));
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