207 lines
9.8 KiB
C
207 lines
9.8 KiB
C
/****************************************************************
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The author of this software is David M. Gay.
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Copyright (C) 1998-2000 by Lucent Technologies
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and
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its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appear in all
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copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of Lucent or any of its entities
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not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior
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permission.
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LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
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SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
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IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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****************************************************************/
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/* This is a variation on dtoa.c that converts arbitary binary
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floating-point formats to and from decimal notation. It uses
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double-precision arithmetic internally, so there are still
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various #ifdefs that adapt the calculations to the native
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double-precision arithmetic (any of IEEE, VAX D_floating,
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or IBM mainframe arithmetic).
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Please send bug reports to David M. Gay (dmg at acm dot org,
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with " at " changed at "@" and " dot " changed to ".").
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*/
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/* On a machine with IEEE extended-precision registers, it is
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* necessary to specify double-precision (53-bit) rounding precision
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* before invoking strtod or dtoa. If the machine uses (the equivalent
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* of) Intel 80x87 arithmetic, the call
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* _control87(PC_53, MCW_PC);
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* does this with many compilers. Whether this or another call is
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* appropriate depends on the compiler; for this to work, it may be
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* necessary to #include "float.h" or another system-dependent header
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* file.
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*/
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/* strtod for IEEE-, VAX-, and IBM-arithmetic machines.
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*
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* This strtod returns a nearest machine number to the input decimal
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* string (or sets errno to ERANGE). With IEEE arithmetic, ties are
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* broken by the IEEE round-even rule. Otherwise ties are broken by
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* biased rounding (add half and chop).
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*
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* Inspired loosely by William D. Clinger's paper "How to Read Floating
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* Point Numbers Accurately" [Proc. ACM SIGPLAN '90, pp. 112-126].
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*
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* Modifications:
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*
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* 1. We only require IEEE, IBM, or VAX double-precision
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* arithmetic (not IEEE double-extended).
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* 2. We get by with floating-point arithmetic in a case that
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* Clinger missed -- when we're computing d * 10^n
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* for a small integer d and the integer n is not too
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* much larger than 22 (the maximum integer k for which
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* we can represent 10^k exactly), we may be able to
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* compute (d*10^k) * 10^(e-k) with just one roundoff.
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* 3. Rather than a bit-at-a-time adjustment of the binary
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* result in the hard case, we use floating-point
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* arithmetic to determine the adjustment to within
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* one bit; only in really hard cases do we need to
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* compute a second residual.
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* 4. Because of 3., we don't need a large table of powers of 10
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* for ten-to-e (just some small tables, e.g. of 10^k
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* for 0 <= k <= 22).
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*/
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/*
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* #define IEEE_8087 for IEEE-arithmetic machines where the least
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* significant byte has the lowest address.
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* #define IEEE_MC68k for IEEE-arithmetic machines where the most
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* significant byte has the lowest address.
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* #define Long int on machines with 32-bit ints and 64-bit longs.
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* #define Sudden_Underflow for IEEE-format machines without gradual
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* underflow (i.e., that flush to zero on underflow).
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* #define IBM for IBM mainframe-style floating-point arithmetic.
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* #define VAX for VAX-style floating-point arithmetic (D_floating).
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* #define No_leftright to omit left-right logic in fast floating-point
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* computation of dtoa and gdtoa. This will cause modes 4 and 5 to be
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* treated the same as modes 2 and 3 for some inputs.
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* #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3.
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* #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines
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* that use extended-precision instructions to compute rounded
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* products and quotients) with IBM.
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* #define ROUND_BIASED for IEEE-format with biased rounding and arithmetic
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* that rounds toward +Infinity.
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* #define ROUND_BIASED_without_Round_Up for IEEE-format with biased
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* rounding when the underlying floating-point arithmetic uses
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* unbiased rounding. This prevent using ordinary floating-point
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* arithmetic when the result could be computed with one rounding error.
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* #define Inaccurate_Divide for IEEE-format with correctly rounded
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* products but inaccurate quotients, e.g., for Intel i860.
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* #define NO_LONG_LONG on machines that do not have a "long long"
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* integer type (of >= 64 bits). On such machines, you can
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* #define Just_16 to store 16 bits per 32-bit Long when doing
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* high-precision integer arithmetic. Whether this speeds things
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* up or slows things down depends on the machine and the number
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* being converted. If long long is available and the name is
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* something other than "long long", #define Llong to be the name,
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* and if "unsigned Llong" does not work as an unsigned version of
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* Llong, #define #ULLong to be the corresponding unsigned type.
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* #define KR_headers for old-style C function headers.
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* #define Bad_float_h if your system lacks a float.h or if it does not
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* define some or all of DBL_DIG, DBL_MAX_10_EXP, DBL_MAX_EXP,
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* FLT_RADIX, FLT_ROUNDS, and DBL_MAX.
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* #define MALLOC your_malloc, where your_malloc(n) acts like malloc(n)
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* if memory is available and otherwise does something you deem
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* appropriate. If MALLOC is undefined, malloc will be invoked
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* directly -- and assumed always to succeed. Similarly, if you
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* want something other than the system's free() to be called to
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* recycle memory acquired from MALLOC, #define FREE to be the
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* name of the alternate routine. (FREE or free is only called in
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* pathological cases, e.g., in a gdtoa call after a gdtoa return in
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* mode 3 with thousands of digits requested.)
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* #define Omit_Private_Memory to omit logic (added Jan. 1998) for making
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* memory allocations from a private pool of memory when possible.
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* When used, the private pool is PRIVATE_MEM bytes long: 2304 bytes,
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* unless #defined to be a different length. This default length
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* suffices to get rid of MALLOC calls except for unusual cases,
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* such as decimal-to-binary conversion of a very long string of
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* digits. When converting IEEE double precision values, the
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* longest string gdtoa can return is about 751 bytes long. For
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* conversions by strtod of strings of 800 digits and all gdtoa
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* conversions of IEEE doubles in single-threaded executions with
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* 8-byte pointers, PRIVATE_MEM >= 7400 appears to suffice; with
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* 4-byte pointers, PRIVATE_MEM >= 7112 appears adequate.
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* #define NO_INFNAN_CHECK if you do not wish to have INFNAN_CHECK
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* #defined automatically on IEEE systems. On such systems,
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* when INFNAN_CHECK is #defined, strtod checks
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* for Infinity and NaN (case insensitively).
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* When INFNAN_CHECK is #defined and No_Hex_NaN is not #defined,
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* strtodg also accepts (case insensitively) strings of the form
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* NaN(x), where x is a string of hexadecimal digits (optionally
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* preceded by 0x or 0X) and spaces; if there is only one string
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* of hexadecimal digits, it is taken for the fraction bits of the
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* resulting NaN; if there are two or more strings of hexadecimal
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* digits, each string is assigned to the next available sequence
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* of 32-bit words of fractions bits (starting with the most
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* significant), right-aligned in each sequence.
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* Unless GDTOA_NON_PEDANTIC_NANCHECK is #defined, input "NaN(...)"
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* is consumed even when ... has the wrong form (in which case the
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* "(...)" is consumed but ignored).
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* #define MULTIPLE_THREADS if the system offers preemptively scheduled
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* multiple threads. In this case, you must provide (or suitably
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* #define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed
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* by FREE_DTOA_LOCK(n) for n = 0 or 1. (The second lock, accessed
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* in pow5mult, ensures lazy evaluation of only one copy of high
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* powers of 5; omitting this lock would introduce a small
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* probability of wasting memory, but would otherwise be harmless.)
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* You must also invoke freedtoa(s) to free the value s returned by
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* dtoa. You may do so whether or not MULTIPLE_THREADS is #defined.
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* #define IMPRECISE_INEXACT if you do not care about the setting of
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* the STRTOG_Inexact bits in the special case of doing IEEE double
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* precision conversions (which could also be done by the strtod in
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* dtoa.c).
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* #define NO_HEX_FP to disable recognition of C9x's hexadecimal
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* floating-point constants.
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* #define -DNO_ERRNO to suppress setting errno (in strtod.c and
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* strtodg.c).
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* #define NO_STRING_H to use private versions of memcpy.
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* On some K&R systems, it may also be necessary to
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* #define DECLARE_SIZE_T in this case.
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* #define USE_LOCALE to use the current locale's decimal_point value.
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*/
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#ifndef GDTOAIMP_H_INCLUDED
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#define GDTOAIMP_H_INCLUDED
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#include "mprec.h"
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#include "gdtoa.h"
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#ifndef __SINGLE_THREAD__
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#define MULTIPLE_THREADS
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#endif
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#define dtoa __dtoa
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#define gdtoa __gdtoa
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#define freedtoa __freedtoa
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#define dtoa_result __dtoa_result_D2A
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#define nrv_alloc __nrv_alloc_D2A
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#define quorem __quorem_D2A
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#define rshift __rshift_D2A
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#define rv_alloc __rv_alloc_D2A
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#define trailz __trailz_D2A
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extern char *dtoa_result;
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extern char *nrv_alloc ANSI((struct _reent *, char*, char **, int));
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extern int quorem ANSI((Bigint*, Bigint*));
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extern void rshift ANSI((Bigint*, int));
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extern char *rv_alloc ANSI((struct _reent *, int));
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extern int trailz ANSI((Bigint*));
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#endif /* GDTOAIMP_H_INCLUDED */
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