[Python-checkins] r71319 - python/branches/py3k-short-float-repr/Python/dtoa.c

[mark.dickinson]

Author: mark.dickinson
Date: Mon Apr  6 21:34:08 2009
New Revision: 71319

Log:
Remove some no-longer-applicable comments


Modified:
   python/branches/py3k-short-float-repr/Python/dtoa.c

Modified: python/branches/py3k-short-float-repr/Python/dtoa.c
==============================================================================
--- python/branches/py3k-short-float-repr/Python/dtoa.c	(original)
+++ python/branches/py3k-short-float-repr/Python/dtoa.c	Mon Apr  6 21:34:08 2009
@@ -106,10 +106,6 @@
  * #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 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.
  * #define Honor_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3
  *	and strtod and dtoa should round accordingly.  Unless Trust_FLT_ROUNDS
  *	is also #defined, fegetround() will be queried for the rounding mode.
@@ -120,34 +116,6 @@
  *	portable than using FLT_FOUNDS directly.
  * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3
  *	and Honor_FLT_ROUNDS is not #defined.
- * #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.
- * #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 dtoa call after a dtoa 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,
@@ -159,63 +127,6 @@
  *	all dtoa conversions 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).  On some systems
- *	(e.g., some HP systems), it may be necessary to #define NAN_WORD0
- *	appropriately -- to the most significant word of a quiet NaN.
- *	(On HP Series 700/800 machines, -DNAN_WORD0=0x7ff40000 works.)
- *	When INFNAN_CHECK is #defined and No_Hex_NaN is not #defined,
- *	strtod also accepts (case insensitively) strings of the form
- *	NaN(x), where x is a string of hexadecimal digits and spaces;
- *	if there is only one string of hexadecimal digits, it is taken
- *	for the 52 fraction bits of the resulting NaN; if there are two
- *	or more strings of hex digits, the first is for the high 20 bits,
- *	the second and subsequent for the low 32 bits, with intervening
- *	white space ignored; but if this results in none of the 52
- *	fraction bits being on (an IEEE Infinity symbol), then NAN_WORD0
- *	and NAN_WORD1 are used instead.
- * #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 NO_IEEE_Scale to disable new (Feb. 1997) logic in strtod that
- *	avoids underflows on inputs whose result does not underflow.
- *	If you #define NO_IEEE_Scale on a machine that uses IEEE-format
- *	floating-point numbers and flushes underflows to zero rather
- *	than implementing gradual underflow, then you must also #define
- *	Sudden_Underflow.
- * #define USE_LOCALE to use the current locale's decimal_point value.
- * #define SET_INEXACT if IEEE arithmetic is being used and extra
- *	computation should be done to set the inexact flag when the
- *	result is inexact and avoid setting inexact when the result
- *	is exact.  In this case, dtoa.c must be compiled in
- *	an environment, perhaps provided by #include "dtoa.c" in a
- *	suitable wrapper, that defines two functions,
- *		int get_inexact(void);
- *		void clear_inexact(void);
- *	such that get_inexact() returns a nonzero value if the
- *	inexact bit is already set, and clear_inexact() sets the
- *	inexact bit to 0.  When SET_INEXACT is #defined, strtod
- *	also does extra computations to set the underflow and overflow
- *	flags when appropriate (i.e., when the result is tiny and
- *	inexact or when it is a numeric value rounded to +-infinity).
- * #define NO_ERRNO if strtod should not assign errno = ERANGE when
- *	the result overflows to +-Infinity or underflows to 0.
- * #define NO_HEX_FP to omit recognition of hexadecimal floating-point
- *	values by strtod.
- * #define NO_STRTOD_BIGCOMP (on IEEE-arithmetic systems only for now)
- *	to disable logic for "fast" testing of very long input strings
- *	to strtod.  This testing proceeds by initially truncating the
- *	input string, then if necessary comparing the whole string with
- *	a decimal expansion to decide close cases. This logic is only
- *	used for input more than STRTOD_DIGLIM digits long (default 40).
  */
 
 /* Linking of Python's #defines to Gay's #defines starts here. */