newlib-cygwin/newlib/libc/stdlib/gdtoaimp.h

/****************************************************************

The author of this software is David M. Gay.

Copyright (C) 1998-2000 by Lucent Technologies
All Rights Reserved

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****************************************************************/

/* This is a variation on dtoa.c that converts arbitary binary
   floating-point formats to and from decimal notation.  It uses
   double-precision arithmetic internally, so there are still
   various #ifdefs that adapt the calculations to the native
   double-precision arithmetic (any of IEEE, VAX D_floating,
   or IBM mainframe arithmetic).

   Please send bug reports to David M. Gay (dmg at acm dot org,
   with " at " changed at "@" and " dot " changed to ".").
 */

/* On a machine with IEEE extended-precision registers, it is
 * necessary to specify double-precision (53-bit) rounding precision
 * before invoking strtod or dtoa.  If the machine uses (the equivalent
 * of) Intel 80x87 arithmetic, the call
 *	_control87(PC_53, MCW_PC);
 * does this with many compilers.  Whether this or another call is
 * appropriate depends on the compiler; for this to work, it may be
 * necessary to #include "float.h" or another system-dependent header
 * file.
 */

/* strtod for IEEE-, VAX-, and IBM-arithmetic machines.
 *
 * This strtod returns a nearest machine number to the input decimal
 * string (or sets errno to ERANGE).  With IEEE arithmetic, ties are
 * broken by the IEEE round-even rule.  Otherwise ties are broken by
 * biased rounding (add half and chop).
 *
 * Inspired loosely by William D. Clinger's paper "How to Read Floating
 * Point Numbers Accurately" [Proc. ACM SIGPLAN '90, pp. 112-126].
 *
 * Modifications:
 *
 *	1. We only require IEEE, IBM, or VAX double-precision
 *		arithmetic (not IEEE double-extended).
 *	2. We get by with floating-point arithmetic in a case that
 *		Clinger missed -- when we're computing d * 10^n
 *		for a small integer d and the integer n is not too
 *		much larger than 22 (the maximum integer k for which
 *		we can represent 10^k exactly), we may be able to
 *		compute (d*10^k) * 10^(e-k) with just one roundoff.
 *	3. Rather than a bit-at-a-time adjustment of the binary
 *		result in the hard case, we use floating-point
 *		arithmetic to determine the adjustment to within
 *		one bit; only in really hard cases do we need to
 *		compute a second residual.
 *	4. Because of 3., we don't need a large table of powers of 10
 *		for ten-to-e (just some small tables, e.g. of 10^k
 *		for 0 <= k <= 22).
 */

/*
 * #define IEEE_8087 for IEEE-arithmetic machines where the least
 *	significant byte has the lowest address.
 * #define IEEE_MC68k for IEEE-arithmetic machines where the most
 *	significant byte has the lowest address.
 * #define Long int on machines with 32-bit ints and 64-bit longs.
 * #define Sudden_Underflow for IEEE-format machines without gradual
 *	underflow (i.e., that flush to zero on underflow).
 * #define IBM for IBM mainframe-style floating-point arithmetic.
 * #define VAX for VAX-style floating-point arithmetic (D_floating).
 * #define No_leftright to omit left-right logic in fast floating-point
 *	computation of dtoa and gdtoa.  This will cause modes 4 and 5 to be
 *	treated the same as modes 2 and 3 for some inputs.
 * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3.
 * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines
 *	that use extended-precision instructions to compute rounded
 *	products and quotients) with IBM.
 * #define ROUND_BIASED for IEEE-format with biased rounding and arithmetic
 *	that rounds toward +Infinity.
 * #define ROUND_BIASED_without_Round_Up for IEEE-format with biased
 *	rounding when the underlying floating-point arithmetic uses
 *	unbiased rounding.  This prevent using ordinary floating-point
 *	arithmetic when the result could be computed with one rounding error.
 * #define Inaccurate_Divide for IEEE-format with correctly rounded
 *	products but inaccurate quotients, e.g., for Intel i860.
 * #define NO_LONG_LONG on machines that do not have a "long long"
 *	integer type (of >= 64 bits).  On such machines, you can
 *	#define Just_16 to store 16 bits per 32-bit Long when doing
 *	high-precision integer arithmetic.  Whether this speeds things
 *	up or slows things down depends on the machine and the number
 *	being converted.  If long long is available and the name is
 *	something other than "long long", #define Llong to be the name,
 *	and if "unsigned Llong" does not work as an unsigned version of
 *	Llong, #define #ULLong to be the corresponding unsigned type.
 * #define KR_headers for old-style C function headers.
 * #define Bad_float_h if your system lacks a float.h or if it does not
 *	define some or all of DBL_DIG, DBL_MAX_10_EXP, DBL_MAX_EXP,
 *	FLT_RADIX, FLT_ROUNDS, and DBL_MAX.
 * #define MALLOC your_malloc, where your_malloc(n) acts like malloc(n)
 *	if memory is available and otherwise does something you deem
 *	appropriate.  If MALLOC is undefined, malloc will be invoked
 *	directly -- and assumed always to succeed.  Similarly, if you
 *	want something other than the system's free() to be called to
 *	recycle memory acquired from MALLOC, #define FREE to be the
 *	name of the alternate routine.  (FREE or free is only called in
 *	pathological cases, e.g., in a gdtoa call after a gdtoa return in
 *	mode 3 with thousands of digits requested.)
 * #define Omit_Private_Memory to omit logic (added Jan. 1998) for making
 *	memory allocations from a private pool of memory when possible.
 *	When used, the private pool is PRIVATE_MEM bytes long:  2304 bytes,
 *	unless #defined to be a different length.  This default length
 *	suffices to get rid of MALLOC calls except for unusual cases,
 *	such as decimal-to-binary conversion of a very long string of
 *	digits.  When converting IEEE double precision values, the
 *	longest string gdtoa can return is about 751 bytes long.  For
 *	conversions by strtod of strings of 800 digits and all gdtoa
 *	conversions of IEEE doubles in single-threaded executions with
 *	8-byte pointers, PRIVATE_MEM >= 7400 appears to suffice; with
 *	4-byte pointers, PRIVATE_MEM >= 7112 appears adequate.
 * #define NO_INFNAN_CHECK if you do not wish to have INFNAN_CHECK
 *	#defined automatically on IEEE systems.  On such systems,
 *	when INFNAN_CHECK is #defined, strtod checks
 *	for Infinity and NaN (case insensitively).
 *	When INFNAN_CHECK is #defined and No_Hex_NaN is not #defined,
 *	strtodg also accepts (case insensitively) strings of the form
 *	NaN(x), where x is a string of hexadecimal digits (optionally
 *	preceded by 0x or 0X) and spaces; if there is only one string
 *	of hexadecimal digits, it is taken for the fraction bits of the
 *	resulting NaN; if there are two or more strings of hexadecimal
 *	digits, each string is assigned to the next available sequence
 *	of 32-bit words of fractions bits (starting with the most
 *	significant), right-aligned in each sequence.
 *	Unless GDTOA_NON_PEDANTIC_NANCHECK is #defined, input "NaN(...)"
 *	is consumed even when ... has the wrong form (in which case the
 *	"(...)" is consumed but ignored).
 * #define MULTIPLE_THREADS if the system offers preemptively scheduled
 *	multiple threads.  In this case, you must provide (or suitably
 *	#define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed
 *	by FREE_DTOA_LOCK(n) for n = 0 or 1.  (The second lock, accessed
 *	in pow5mult, ensures lazy evaluation of only one copy of high
 *	powers of 5; omitting this lock would introduce a small
 *	probability of wasting memory, but would otherwise be harmless.)
 *	You must also invoke freedtoa(s) to free the value s returned by
 *	dtoa.  You may do so whether or not MULTIPLE_THREADS is #defined.
 * #define IMPRECISE_INEXACT if you do not care about the setting of
 *	the STRTOG_Inexact bits in the special case of doing IEEE double
 *	precision conversions (which could also be done by the strtod in
 *	dtoa.c).
 * #define NO_HEX_FP to disable recognition of C9x's hexadecimal
 *	floating-point constants.
 * #define -DNO_ERRNO to suppress setting errno (in strtod.c and
 *	strtodg.c).
 * #define NO_STRING_H to use private versions of memcpy.
 *	On some K&R systems, it may also be necessary to
 *	#define DECLARE_SIZE_T in this case.
 * #define USE_LOCALE to use the current locale's decimal_point value.
 */

#ifndef GDTOAIMP_H_INCLUDED
#define GDTOAIMP_H_INCLUDED
#include "mprec.h"
#include "gdtoa.h"

#ifndef __SINGLE_THREAD__
#define MULTIPLE_THREADS
#endif

#define dtoa __dtoa
#define gdtoa __gdtoa
#define freedtoa __freedtoa

#define dtoa_result __dtoa_result_D2A
#define nrv_alloc __nrv_alloc_D2A
#define quorem __quorem_D2A
#define rshift __rshift_D2A
#define rv_alloc __rv_alloc_D2A
#define trailz __trailz_D2A

extern char *dtoa_result;
extern char *nrv_alloc ANSI((struct _reent *, char*, char **, int));
extern int quorem ANSI((Bigint*, Bigint*));
extern void rshift ANSI((Bigint*, int));
extern char *rv_alloc ANSI((struct _reent *, int));
extern int trailz ANSI((Bigint*));

#endif /* GDTOAIMP_H_INCLUDED */