xref: /freebsd/contrib/gdtoa/changes (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)

Sun Jun 30 13:48:26 EDT 1991:
  dtoa.c: adjust dtoa to allow negative ndigits for modes 3,5,7,9
(fixed-point mode); fix rounding bug in these modes when the input
d (to be converted) satisfies 10^-(ndigits+1) <= |d| < 10^-ndigits ,
i.e., when the result, before rounding, would be empty but might
round to one digit.  Adjust the decpt returned in these modes when
the result is empty (i.e., when |d| <= 5 * 10^-ndigits).

Tue Jul  2 21:44:00 EDT 1991
  Correct an inefficiency introduced 2 days ago in dtoa's handling of
integers in modes 0, 1.

Mon Sep  9 23:29:38 EDT 1991
  dtoa.c: remove superfluous declaration of size_t.

Sun Oct  6 15:34:15 EDT 1991
  dtoa.c: fix another bug in modes 3,5,7,9 when the result, before
rounding, would be empty, but rounds to one digit: *decpt was low by
one.

Sat Jan 18 12:30:04 EST 1992
  dtoa.c: add some #ifdef KR_headers lines relevant only if IBM is
defined; for input decimal strings representing numbers too large, have
strtod return HUGE_VAL only if __STDC__ is defined; otherwise have it
return +-Infinity for IEEE arithmetic, +- the largest machine number
for IBM and VAX arithmetic.  (If __STDC__ is not defined, HUGE_VAL may
not be defined either, or it may be wrong.)

Mon Apr 27 23:13:43 EDT 1992
  dtoa.c: tweak strtod (one-line addition) so the end-pointer = start
pointer when the input has, e.g., only white space.

Thu May  7 18:04:46 EDT 1992
  dtoa.c: adjust treatment of exponent field (in strtod) to behave
reasonably with huge numbers and 16-bit ints.

Fri Jun 19 08:29:02 EDT 1992
  dtoa.c: fix a botch in placement of #ifdef __cplusplus (which only
matters if you're using a C++ compiler).

Wed Oct 21 11:23:07 EDT 1992
  dtoa.c: add #ifdef Bad_float_h lines for systems with missing or
inferior float.h .

Thu Apr 22 07:54:48 EDT 1993
  dtoa.c: change < to <= in line 2059:
<	for(result_k = 0; sizeof(Bigint) - sizeof(unsigned long) + j < i;
---
>	for(result_k = 0; sizeof(Bigint) - sizeof(unsigned long) + j <= i;
With 32-bit ints, the former could give too small a block for the return
value when, e.g., mode = 2 or 4 and ndigits = 24 (16 for 16-bit ints).

Mon Jun 21 12:56:42 EDT 1993
  dtoa.c: tweak to work with 32-bit ints and 64-bit longs
when compiled with -DLong=int .

Wed Jan 26 11:09:16 EST 1994
  dtoa.c: fix bug in strtod's handling of numbers with very
negative exponents (e.g. 1.8826e-512), which should underflow to 0;
fix storage leak in strtod with underflows and overflows near
the underflow and overflow thresholds.

Mon Feb 28 11:37:30 EST 1994
  dtoa.c:
85a86,89
>  * #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.
87a92,95
> #ifndef MALLOC
> #define MALLOC malloc
> #endif
>
352c360
< 		rv = (Bigint *)malloc(sizeof(Bigint) + (x-1)*sizeof(Long));
---
> 		rv = (Bigint *)MALLOC(sizeof(Bigint) + (x-1)*sizeof(Long));

Thu Mar  3 16:56:39 EST 1994
  dtoa.c: if MALLOC is #defined, declare it.

Wed Jan  4 15:45:34 EST 1995
  dtoa.c: add CONST qualification to tens, bigtens, tinytens (for use
on embedded systems with little spare RAM).

Fri Mar  1 08:55:39 EST 1996
  g_fmt.c: honor the sign of 0 and return the first argument (buf).

Sat Jul  6 07:59:28 EDT 1996
  dtoa.c: cosmetic changes: "ULong" rather than "unsigned Long";
update comments to reflect AT&T breakup.

Mon Aug  5 23:31:24 EDT 1996
  dtoa.c: add comment about invoking _control87(PC_53, MCW_PC)
(or the equivalent) on 80x87 machines before calling strtod or dtoa.

Tue Dec 17 15:01:56 EST 1996
  dtoa.c: new #define possibilities: #define INFNAN_CHECK to have
strtod check (case insensitively) for "Infinity" and "NaN" on machines
with IEEE arithmetic; #define MULTIPLE_THREADS if the system offers
preemptively scheduled multiple threads, in which case you must supply
routines ACQUIRE_DTOA_LOCK(n) and FREE_DTOA_LOCK(n) (n = 0 or 1).
New void freedtoa(char*) for freeing values returned by dtoa; use of
freedtoa() is required if MULTIPLE_THREADS is #defined, and is merely
recommended otherwise.
  g_fmt.c: adjusted to invoke freedtoa().

Wed Feb 12 00:40:01 EST 1997
  dtoa.c: strtod: on IEEE systems, scale to avoid intermediate
underflows when the result does not underflow; compiling with
-DNO_IEEE_Scale restores the old logic.  Fix a bug, revealed by
input string 2.2250738585072012e-308, in treating input just less
than the smallest normalized number.  (The bug introduced an extra
ULP of error in this special case.)

Tue May 12 11:13:04 EDT 1998
  dtoa.c: strtod: fix a glitch introduced with the scaling of 19970212
that caused one-bit rounding errors in certain denormal numbers, such
as 8.44291197326099e-309, which was read as 8.442911973260987e-309.
Remove #ifdef Unsigned_Shifts logic in favor of unsigned arithmetic.
Unless compiled with -DNO_LONG_LONG, use 64-bit arithmetic where
possible.

Fri May 15 07:49:07 EDT 1998
  dtoa.c: strtod: fix another glitch with scaling to avoid underflow
with IEEE arithmetic, again revealed by the input string
2.2250738585072012e-308, which was rounded to the largest denormal
rather than the smallest normal double precision number.

Wed Aug  5 23:27:26 EDT 1998
  gdtoa.tar.gz: tweaks in response to comments from Shawn C. Sheridan
(with no effect on the resulting .o files except when strtod.c is
compiled with -DNO_ERRNO); bigtens --> bigtens_D2A (a symbol meant
to be private to gdtoa.a).

Sat Sep 12 17:05:15 EDT 1998
  gdtoa.tar.gz: more changes in response to comments from Shawn C.
Sheridan (including repair of a glitch in g_ffmt.c).  For consistency
and possible convenience, there are some new functions and some name
changes to existing ones:
	Old	New
	---	g_xLfmt
	strtoQ	strtopQ
	---	strtopd
	strtodd	strtopdd
	---	strtopf
	strtox	strtopx
	---	strtopxL
	---	strtorxL
	---	strtoIxL
Functions strtopd and strtopf are variations of strtod and strtof,
respectively, which write their results to their final (pointer)
arguments.  Functions strtorf and strtord are now analogous to the
other strtor* functions in that they now have a final pointer
argument to which they write their results, and they return the
int value they get from strtodg.
  The xL family (g_xLfmt, strto[Irp]xL) is a variation of the old x
family (for 80-bit IEEE double-extended precision) that assumes the
storage layout of the Motorola 68881's double-extended format:  80
interesting bits stored in 3 unsigned 32-bit ints (with a "hole", 16
zero bits, in the word that holds the sign and exponent).  The x
family now deals with 80-bit (5 unsigned 16-bit ints) rather than
96-bit arrays (3 unsigned 32-bit ints) that hold its 80-bit
double-extended values.  (This relaxes the alignment requirements of
the x family and results in strto[Ipr]x writing 80 rather than 96 bits
to their final arguments.)
  Each g_*fmt routine now returns a pointer to the null character
that terminates the strings it writes, rather than a pointer to
the beginning of that string (the first argument).  These routines
still return 0 (NULL) if the first argument is too short.
  The second argument to g_dfmt is now pointer (to a double) rather
than a double value.

Thu Oct 29 21:54:00 EST 1998
  dtoa.c: Fix bug in strtod under -DSudden_Underflow and (the default)
-DAvoid_Underflow: some numbers that should have suffered sudden
underflow were scaled inappropriately (giving nonzero return values).
Example: "1e-320" gave -3.6304123742133376e+280 rather than 0.

Mon Nov  2 15:41:16 EST 1998
  dtoa.c: tweak to remove LL suffixes from numeric constants (for
compilers that offer a 64-bit long long type but do not recognize the
LL constants prescribed by C9x, the proposed update to the ANSI/ISO C
standard).  Thanks to Earl Chew for pointing out the existence of such
compilers.
  gdtoa.tar.gz: renamed gdtoa.tgz and updated to incorporate the above
changes (of 29 Oct. and 2 Nov. 1998) to dtoa.c.

Thu Mar 25 17:56:44 EST 1999
  dtoa.c, gdtoa.tgz: fix a bug in strtod's reading of 4.9e-324:
it returned 0 rather than the smallest denormal.

Mon Apr 12 10:39:25 EDT 1999
  gdtoa.tgz: test/ftest.c: change %.7g to %.8g throughout.

Fri Aug 20 19:17:52 EDT 1999
  gdtoa.tgz: gdtoa.c: fix two bugs reported by David Chase (thanks!):
1. An adjustment for denormalized numbers around 503 was off by one.
2. A check for "The special case" around line 551 omitted the condition
that we not be at the bottom of the exponent range.

Mon Sep 13 10:53:34 EDT 1999
  dtoa.c: computationally invisible tweak for the benefit of people
who actually read the code:

2671c2671
< 		 && word0(d) & Exp_mask
---
> 		 && word0(d) & (Exp_mask & Exp_mask << 1)

I.e., in dtoa(), the "special case" does not arise for the smallest
normalized IEEE double.  Thanks to Waldemar Horwat for pointing this
out and suggesting the modified test above.  Also, some tweaks for
compilation with -DKR_headers.
  gdtoa.tgz: gdtoa.c: analogous change:

552c552
< 		if (bbits == 1 && be0 > fpi->emin) {
---
> 		if (bbits == 1 && be0 > fpi->emin + 1) {

This has no effect on the g*fmt.c routines, but might affect the
computation of the shortest decimal string that rounds to the
smallest normalized floating-point number of other precisions.
  gdota.tgz: test/d.out test/dI.out test/dd.out: updated to reflect
previous changes (of 19990820); test/*.c: most test programs modified
to permit #hex input.  See the comments.

Fri Sep 17 01:39:25 EDT 1999
  Try again to update dtoa.c: somehow dtoa.c got put back to a version
from 3 years ago after this "changes" file was updated on 13 Sept. 1999.
One more tweak to omit a warning on some systems:
2671c2671
<		 && word0(d) & (Exp_mask & Exp_mask << 1)
---
>		 && word0(d) & (Exp_mask & ~Exp_msk1)
Plus changes to avoid trouble with aggressively optimizing compilers
(e.g., gcc 2.95.1 under -O2).  On some systems, these changes do not
affect the resulting machine code; on others, the old way of viewing
a double as a pair of ULongs is available with -DYES_ALIAS.

Tue Sep 21 09:21:25 EDT 1999
  gdtoa.tgz: changes analogous to those of 17 Sept. 1999 to dtoa.c to
avoid trouble with aggressively optimizing compilers.

Wed Dec 15 13:14:38 EST 1999
  dtoa.c: tweak to bypass a bug with HUGE_VAL on HP systems.

Mon Jan 17 18:32:52 EST 2000
  dtoa.c and gdtoa.tgz: strtod: set errno = ERANGE on all inputs that
underflow to zero (not just those sufficiently less than the smallest
positive denormalized number).
  gdtoa.tgz: README: point out that compiling with -DNO_ERRNO inhibits
errno assignments (by strtod and the core converter, strtodg).

Tue Jan 18 16:35:31 EST 2000
  dtoa.c and gdtoa.tgz: strtod: modify the test inserted yesterday so
it may work correctly with buggy 80x87 compilers.  (The change matters,
e.g., to Microsoft Visual C++ 4.2 and 6.0.)

Thu Nov  2 21:00:45 EST 2000
  dtoa.c and gdtoa.tgz:
1. Fix bug in test for exact half-way cases of denormalized numbers
   (without -DNO_IEEE_Scale).
2. Compilation with -DNO_ERRNO prevents strtod from assigning
   errno = ERANGE when the result overflows or underflows to 0.
3. With IEEE arithmetic and no -DNO_IEEE_Scale, adjust scaling so
   ulp(d) never returns a denormalized number.  This and other tweaks
   permit strtod and dtoa to work correctly on machines that flush
   underflows to zero but otherwise use IEEE arithmetic without
   Sudden_Underflow being #defined (and with strtod simply returning 0
   instead of denormalized numbers).
4. Compilations with -DUSE_LOCALE causes strtod to use the current
   locale's decimal_point value.
5. Under compilations with -DINFNAN_CHECK, strtod and strtodg (case
   insensitively) treat "inf" the same as "infinity" and, unless
   compiled with -DNo_Hex_NaN, accept "nan(x)", where x is a string of
   hexadecimal digits and spaces, as a NaN whose value is constructed
   from x (as explained in comments near the top of dtoa.c and in
   gdtoaimp.h).
6. The default PRIVATE_MEM is increased slightly (to 2304), and comments
   near the top of dtoa.c provide more discussion of PRIVATE_MEM.
7. Meanings of dtoa modes 4,5,8,9 changed.  See comments in dtoa.c and
   gdtoa.c; modes 4 and 5 may now provide shorter strings that round
   (in round-nearest mode) to the given double value.  (Paxson's
   testbase program is unhappy with this new rounding, as it can
   introduce an error of more than one base-10 ulp when 17 or more
   decimal digits are requested.)
8. With IEEE arithmetic, compilation with -DHonor_FLT_ROUNDS causes
   strtod and dtoa to round according to FLT_ROUNDS:
	0 ==> towards 0,
	1 ==> nearest,
	2 ==> towards +Infinity,
	3 ==> towards -Infinity.
9. With IEEE arithmetic, compilation with -DSET_INEXACT causes extra
   computation (and sometimes slower conversions in dtoa and strtod,
   particularly for dtoa in cases where otherwise some simple floating-
   point computations would suffice) to set the IEEE inexact flag
   correctly.  As comments in dtoa.c explain in more detail, this
   requires compilation in an environment (such as #include "dtoa.c"
   in suitable source) that provides
		int get_inexact(void);
		void clear_inexact(void);
10. On input "-x", return 0 rather than -0.

gdtoa.tgz: gethex.c: adjust logic for reading hex constants to accord
with current wording of the C99 standard.  Previously, I thought hex
constants read by strtod and friends had to have either a decimal point
or an exponent field; p. 307 of the C99 standard states that both are
optional.  Because of the complexity of this reading, it is available
only in the variant of strtod that appears in gdtoa.tgz.

strtodg (gdtoa.tgz): New return value STRTOG_NaNbits (with
STRTOG_NoNumber renumbered).  Allow STRTOG_Neg bit in strtodg returns
for STRTOG_NaN and STRTOG_NaNbits.

gdtoa.tgz: Fix uninitialized variable bug in g_Qfmt.c's handling of NaNs.

Mon Nov 13 14:00:05 EST 2000
  gdtoa.tgz: strtodg:  fix a storage leak and an apparently rare infinite
loop with a boundary case of directed rounding.  Example input to
gdtoa/test/Qtest where the loop bug bit:
	r 3
	35184372088831.999999999999999999999999999999999999
This was revealed by testbase for quad precision Solaris arithmetic;
it did not show up in several other testbase configurations.

Wed Feb  7 12:56:11 EST 2001
  dtoa.c:  fix bug (possible infinite loop, e.g., with
2.47032822920623272e-324) introduced 20001113 in handling the special
case of a power of 2 to be rounded down one ulp.  Add test (required
by changes of 20001113) for the extra special case of 2^-1075 (half
the smallest denormal).
  gdtoa.tgz: corresponding adjustments to strtod.c and strtodg.c.

Tue Mar 13 00:46:09 EST 2001
  gdtoa.tgz: gdtoa/strtodg.c: fix bug in handling values exactly half
an ulp less than the smallest normal floating-point number;
gdtoa/*test.c: fix glitch in handling "n ..." lines (intended to
change "ndig").

Wed Mar  6 10:13:52 EST 2002
  gdtoa.tgz:  add gdtoa/test/strtodt.c and gdtoa/test/testnos3 to test
strtod on hard cases posted by Fred Tydeman to comp.arch.arithmetic on
26 Feb. 1996.  Add comment to gdtoa/README about strtod requiring true
IEEE arithmetic (with 53-bit rounding precision on 80x87 chips).
In gdtoa/test, automate selection of expected output files [xQ]*.out.

Wed Mar  5 10:35:41 EST 2003
  gdtoa.tgz:  fix a bug in strtod's handling of 0-valued 0x... "decimal"
strings.  A fault was possible.  Thanks to David Shultz for reporting
this bug.

Tue Mar 18 09:38:28 EST 2003
  gdtoa.tgz:  fix a glitch in strtodg.c with -DUSE_LOCALE; add #ifdef
USE_LOCALE lines to g__fmt.c (to affect binary --> decimal conversions
via the g*fmt routines), and add comments about -DUSE_LOCALE to README.
In short, compiling strtod.c, strtodg.c, and g__fmt.c with -DUSE_LOCALE
causes them to determine the decimal-point character from the current
locale.  (Otherwise it is '.'.)

Fri Mar 21 16:36:27 EST 2003
  gdtoa.tgz:  gethex.c: add #ifdef USE_LOCAL logic; strtod.c: fix a
glitch in handling 0x... input (the return from gethex was ignored).

Wed Mar 26 15:35:10 EST 2003
  gdtoa.tgz:  gethex.c:  pedantic (and normally invisible) change:
use unsigned char for decimalpoint variable (under -DUSE_LOCALE).

Sat Jan 17 23:58:52 MST 2004
  gdtoa.tgz:  gethex.c:  supply missing parens in test for whether a
denormal result should be zero, correct logic for rounding up when the
result is denormal, and when returning zero or Infinity, set *bp = 0;
strtod.c:  switch on gethex(...)  & STRTOG_Retmask rather than just on
gethex(), and only copybits(..., bb) when bb is nonzero.  This
mattered for underflows and overflows in 0x notation.

Thu Mar 25 22:34:56 MST 2004
 dtoa.c and gdtoa.c/misc.c:  change "(!x & 1)" to "(!x)" to avoid
confusion by human readers -- the object code is unaffected (with
reasonable compilers).

Mon Apr 12 00:44:22 MDT 2004
 dtoa.c and gdtoa.tar.gz:  update contact info. for dmg and correct
page numbers in comment on Steele & White (1990).
 gdtoa.tgz:  add strtodnrp.c for a variant of strtod that is slower
but does not require 53-bit rounding precision on Intel IA32 systems.

Tue Apr 13 00:28:14 MDT 2004
 gdtoa.tgz: strtod.c: fix glitch when both INFNAN_CHECK and No_Hex_NaN
are #defined.  Thanks to David Mendenhall for pointing this bug out.

Wed Jan  5 22:39:17 MST 2005
  gdtoa.tgz:
    gethex.c:  fix the bug reported by Stefan Farfeleder of ignoring a
binary-exponent-part if the converted number is zero.
    strto[pr]x.c: fix bug reported by Stefan Farfeleder in setting the
exponent of denormals (which should be 0, not 1).
    g_xfmt.c: fix a corresponding bug with denormals.
    strtodg.c: fix a bug under IBM (base 16) arithemtic reported
by Greg Alexander:  a correction to the binary exponent for changes to
the exponent of a native double value for avoiding overflow had to be
multiplied by 4 ("e2 <<= 2;").
    Various files: minor tweaks for portability.

Sat Jan 15 15:36:03 MST 2005
  gdtoa.tgz: gethex.c:  fix a glitch introduced last week (and reported
by Stefan Farfelder) with 0x forms with no nonzero digits before the "."
character, e.g., 0x.1 (which was rendered as 0 rather than .0625).
  gdtoa.tgz: many files: add automatic computation of gd_qnan.h for
giving the system-dependent format of a quiet NaN (the one generated
for Infinity - Infinity).  Tweak test/makefile so differences in the
spelling of Infinity ("INF" or "Inf" on some systems) do not matter.
Fix bug in strtod.c and strtodg.c under which, e.g., -.nan was read
as NaN rather than unacceptable input (causing return 0).  Adjust
comments in README about nan(...).  Fix glitch in test/dt.c.

Sun Jan 16 18:22:13 MST 2005
  gdtoa.tgz: strtodg.c: fix long-standing bug in handling input
that rounds up to 2^nbits, e.g., strtof("16777215.5").  Thanks to
Edward Moy for reporting this problem.
  gdtoa.tgz: Fix some bugs with -DJust_16.

Thu Sep 22 22:40:16 MDT 2005
gdtoa.tgz:
  strtod.c: unless prevented by -DNO_FENV_H, include C99's fenv.h
and with hex input, get the current rounding mode from fegetround().
With decimal input, strtod honors the rounding mode automatically.
Thanks to David Schultz (das at FreeBSD dot ORG) for pointing
  strtodg.c: fix a bug with handling numbers very near the largest
possible one, which were sometimes incorrectly converted to Infinity.
Thanks to Edward Moy (emoy at apple dot com) for pointing this out.
  g_Qfmt.c: change strcpy to strcp.  Thanks to J. T. Conklin
(jtc at acorntoolworks dot com) for pointing this out.
  test/xtest.c:  fix some subscript bugs.
  test/x.ou0, test/x.ou1, test/xL.: update in response to the above fix to
test/xtest.c.
  test/makefile:  add -lm to some link lines (needed for fegetround).

Sun Jan 21 20:26:44 MST 2007
gdtoa.tgz:
  strtodg.c:  fix a botch in the test of whether to increase rvbits
before terminating the big for(;;) loop with dsign true:  change
	if (hi0bits(rvb->x[(rvb->wds - 1) >> kshift])
			!= j)
		rvbits++;
to
	if (hi0bits(rvb->x[rvb->wds - 1]) != j)
		rvbits++;
Example of input where this bug bit:  1.9e27.  Thanks to Edward Moy
<emoy@apple.com> for providing this example.  Also, simplify the
preceding computation of j.
  test/README:  add comment that strtodt needs to operate with 53-bit
rounding precision on Intel x86 systems, and add a pointer to Paxson's
paper.

Sat Mar 15 11:44:31 MDT 2008
  dtoa.c and gdtoa.tgz:  with -DINFNAN_CHECK and without
-DGDOTA_NON_PEDANTIC_NANCHECK, conform to the ill-advised prescription
in the C99 standard of consuming (...)  in "nan(...)"  even when ...
is not of the expected form.  Allow an optional 0x or 0X to precede
the string of hex digits in the expected form of ... .
  gdtoa.tgz: gethex.c: have, e.g., strtod("0xyz",&se) set se to "xyz".
Previously it was incorrectly set to "0xyz".

Thu Aug 28 22:37:35 MDT 2008
  dtoa.c and gdtoa.tgz:  Fix a bug in strtod when compiled with
-DHonor_FLT_ROUNDS:  in rounding modes other than "to nearest",
strtod looped on input larger than and within a factor of 2 of
the largest finite floating-point number.  Since FLT_ROUNDS is buggy
on some (Linux) systems in that it does not reflect calls on
fesetround(), when Honor_FLT_ROUNDS is #defined, get the curren
rounding mode from fegetround() rather than FLT_ROUNDS, unless
Trust_FLT_ROUNDS is also #defined.
  gdtoa/test/getround.c in gdtoa.tgz: simply report the current
rounding mode when the input line is "r" by itself.  (Previously it
did so, but also complained of invalid input.)
  gdtoa/gethex.c: fix an off-by-one bug in a rounding test; detect and
deal with huge exponents (positive or negative).  This affected the
reading of hexadecimal floating-point values (0x...).  Also set errno
to ERANGE on out-of-range values (unless compiled with -DNO_ERRNO).
  gdtoa/strtod.c: adjust scaling of tinytens[4] (as in dtoa.c) to
avoid double rounding when dealing with numbers near the bottom of
the exponent range.

Sat Aug 30 23:37:07 MDT 2008
  gdtoa/gethex.c: ensure *bp is set to something (NULL if nothing else).
  Bring gdtoa/xsum0.out and gdtoa/test/xsum0.out up to date.

Tue Sep  9 22:08:30 MDT 2008
  gdtoa/strto*.c and gdtoa/*fmt.c:  if compiled with -DUSE_LOCALE, use
the current locale's decimal point character string.
  gdtoa/gdtoa.c: trim trailing zeros in a missed case (e.g., ndigits = 6
on 1020302).
  dtoa.c and gdtoa/strtod.c: on systems with IEEE arithmetic (and without
NO_ERRNO being defined) set ERANGE for denormal values as well as real
underflows.
  gdtoa/strtodg.c:  fix an off-by-one bug in rounding to the largest
representable magnitude when nbits is a multiple of 32.
  gdtoa/*fmt.c and gdtoa/gdtoa.h:  bufsize changed from unsigned to size_t.
  gdtoaimp.h, *fmt.c:  change in calling sequence to internal g__fmt(),
which now explicitly checks bufsize.
  Relevant routines (see README) honor the current rounding mode if
compiled with -DHonor_FLT_ROUNDS on IEEE-arithmetic systems that provide
the C99 fegetround() function.
  gdtoa/test/getround.c can optionally be compiled with
-DHonor_FLT_ROUNDS and/or -DUSE_MY_LOCALE for manual testing of gdtoa.a
compiled with -DHonor_FLT_ROUNDS or -DUSE_LOCALE.

Fri Oct 10 20:07:15 MDT 2008
  gdtoa/gethex.c:  fix a bug reading hexadecimal floating-point values
starting with "0xd" for a nonzero digit d (such as "0x1.0002p3").  The
bug caused the values to be read as zero with endptr set incorrectly.

Tue Oct 28 00:14:08 MDT 2008
  gdtoa/strtod.c: fix a comment glitch (with commented {}).

Tue Nov 11 23:05:25 MST 2008
  gdtoa:  fix a glitch in the strto* routines when compiled with
-DUSE_LOCALE and the locale's decimal-point string is two or more
characters long.  Wrong conversions were then possible.

Fri Dec  5 18:20:36 MST 2008
  gdtoa.tgz: fix bugs with reading C99-style hexadecimal floating-point
values when compiled with -DPack_16; on IEEE-arithmetic systems, make
INFNAN_CHECK the default unless NO_INFNAN_CHECK is #defined.  (This is
consistent with dtoa.c, which has worked this way for a while.)
  dtoa.c:  add recognition of C99-style hexadecimal floating-point
values (unless compiled with NO_HEX_FP is #defined).

Thu Dec 11 23:10:23 MST 2008
  dtoa.c: omit an unused variable.

Fri Jan  2 22:45:33 MST 2009
  dtoa.c: tweak to banish some compiler warnings.

Sun Mar  1 20:57:22 MST 2009
  dtoa.c, gdtoa/{g__fmt.c, gethex.c, strtod.c, strtodg.c}: change malloc
to MALLOC.
  dtoa.c and gdtoa/gdtoaimp.h and gdtoa/misc.c:  reduce Kmax, and use
MALLOC and FREE or free for huge blocks, which are possible only in
pathological cases, such as dtoa calls in mode 3 with thousands of
digits requested, or strtod() calls with thousand of digits.  For the
latter case, I have an alternate approach that runs much faster
and uses less memory, but finding time to get it ready for distribution
may take a while.

Mon Mar 16 00:32:43 MDT 2009
  dtoa.c:  Fix a bug under -DUSE_LOCALE in handling "decimal point"
strings more than one character long.
  dtoa.c and gdtoa/misc.c:  Remove a buggy test activated with
-DDEBUG.
  dtoa.c and gdtoa/gdtoa.c: simplify logic for "4 leading 0 bits".
  dtoa.c:  Add logic (that can be disabled with -DNO_STRTOD_BIGCOMP
and that) to strtod for more efficiently handling a very long input
string.  It 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), and for now only applies to
IEEE arithmetic (for want of other kinds of platforms on which to run
tests).  This only appears worthwhile for absurdly long input strings,
so a corresponding update to gdtoa does not seem warranted.
  dtoa.c, gdtoa.tgz:  tweaks (mostly adding unnecessary parens) to
silence "gcc -Wall" warnings.  Aside from a couple of minor changes
to banish erroneous warnings about uninitialized variables, the tweaks
do not affect the generated object code.

Sat Apr 11 23:25:58 MDT 2009
  dtoa.c: fix glitch in compiling with -DNo_Hex_NaN and the bug of
accepting (e.g.) ".nan" or ".inf" as NaN or Infinity.
  gdtoa.tgz: tweaks to silence warnings from "gcc -Wstrict-aliasing=2";
update xsum0.out files.

Sun Apr 19 23:40:24 MDT 2009
  dtoa.c, gdtoa/misc.c:  do not attempt to allocate large memory blocks
from the private memory pool (which was an unlikely event, but a bug).
  gdtoa/strtopx.c, gdtoa/strtopxL.c, gdtoa/strtorx.c, gdtoa/strtorxL.c:
supply explicit bit for Infinity.  Note that the Q routines (which do
not supply this bit) are appropriate for Sparc quad precision (probably
known as long double with most current compilers).

Wed Dec  9 08:14:52 MST 2009
  gdtoa.tgz:  add gdtoa/printf.c* and modify makefile so "make Printf"
adds a printf to gdtoa.a (to be accessed with #include "stdio1.h" to
get gdtoa/stdio1.h, which you might install in some standard place).
On Intel/AMD i386, x86_64, and Sparc systems, this adds formats %La,
%Le, %Lf and %Lg to handle long double.  On x86_64 systems, it also
adds %Lqa, %Lqe, %Lqf and %Lqg to handle 128-bit bit types (called
__float128 by gcc and _Quad by the Intel compiler).  In gdtoa/test,
"make pf_test" tests this printf (provided the system is an i386,
x86_64, or Sparc system).  On x86_64 systems, "make pf_testLq" tests
the %Lq...  formats (briefly).

Mon Jan 11 22:25:17 MST 2010
  dtoa.c: fix a minor performance bug and, under compilation with -DDEBUG,
an erroneous error message "oversize b in quorem" in strtod's processing
of some input that underflows to zero.  Also fix a bug in bigcomp()'s
handling of numbers that will scale to denormal values.  The increments
that bigcomp applied were ignoring the effects of denormalization.

Sat Jan 23 00:25:54 MST 2010
  dtoa.c:  Fix some glitches in recently introduced changes meant to
speed up returns in pedantic cases.  In quorem, adjust #ifdef DEBUG
stuff so it does not complain when bigcomp() calls quorem on input
near the smallest representable number and rounding up by a bit causes
a quorem return > 9 (which in this case is not a bug).  Fix a memory
leak in the unlikely case of overflow only being detected after some
high-precision integer computations.  Fix an off-by-one bug in
handling a large number of digits with a few nonzero digits, followed
by many zeros, and then some nonzero digits.  (This does not happen
with sensible input.)  Fix an off-by-one bug in a recently introduced
quick test for underflow (i.e., zero result) on input at the bottom of
the exponent range.  Thanks to Mark Dickinson for pointing these bugs
out.

  dtoa.c and gdtoa/strtod.c:  Fix an obscure bug in strtod's handling
of some inputs of many digits at the bottom of the exponent range:
results were sometimes off by a bit when gdtoa/strtod.c or dtoa.c was
compiled without -DNO_IEEE_SCALE and, for dtoa.c, when compiled with
-DNO_STRTOD_BIGCOMP.

  gdtoa/test/testnos3: add some examples that went wrong before
the present changes.

Sat Jan 23 23:29:02 MST 2010
  dtoa.c: more tweaks relevant only to absurd input.

Tue Feb  2 23:05:34 MST 2010
  dtoa.c: add test for setting errno = ERANGE when input of many digits
is rounded to Infinity or underflows to zero.  Fix a memory leak in
such instances.
  gdtoa/strtod.c: make some corresponding changes.

Wed Jul  7 09:25:46 MDT 2010
  dtoa.c:  adjust to use bigcomp when necessary when compiled with
-DHonor_FLT_ROUNDS (and without -DNO_STRTOD_BIGCOMP), and the rounding
mode is torwards +Infinity.  An input (supplied by Rick Regan
<exploringbinary@gmail.com>) where this matters is
1.100000000000000088817841970012523233890533447265626
  gdtoa/strtod.c:  fix errors (introduced 20090411) when compiled
with -DHonor_FLT_ROUNDS.

Wed Sep 15 09:00:26 MDT 2010
  dtoa.c, gdtoa/dtoa.c, gdtoa/gdtoa.c:  fix bugs with -DROUND_BIASED
pointed out by Jay Foad.

Mon Sep 27 13:43:30 MDT 2010
  gdtoa/gdtoa.c: fix a glitch (not revealed by compilation) in the
changes of 15 Sept. 2010.

Fri Nov  5 13:02:41 MDT 2010
  dtoa.c:  fix a bug related to bigcomp:  decimal strings with all
zeros before the decimal point more than 40 significant digits that
required use of bigcomp might be converted very incorrectly.
Example: .010000000000000000057612911342378542997169 .
Thanks to Rick Regan <exploringbinary@gmail.com> for reporting the
symptoms and providing an example.

20110403:
  dtoa.c, gdtoa/gdtoaimp.h, gdtoa/strtod.c:  if
ROUND_BIASED_without_Round_Up is #defined, assume ROUND_BIASED and
omit the quick computation that would use ordinary arithmetic to
compute the correctly rounded result with one rounding error.  If you
want biased rounding with IEEE-style format "double" and will operate
with rounding toward +Infinity, it suffices to #define ROUND_BIASED
(and thus retain the quick computation when it is appropriate).
  gdtoa/gdtoa.h: change default Long from long to int (with the goal
of portability when compiling without -DLong=... specified).  On some
64-bit systems, long is a 64-bit type; we need a 32-bit type here.
  dtoa.c, gdtoa/gdtoa.c: fix a glith with ndigits with mode = 4 at
the bottom of the exponent range, e.g., 1e-323.