Support larger TIMEs in (time-convert TIME t)

Also, improve the doc to match current behavior.
* doc/lispref/os.texi (Time Conversion): Document that
time-convert signals an error for infinite or NaN args,
and that (time-convert TIME t) is exact otherwise.
Mention float-time as an alternative to time-convert.
(Time Calculations): Document that time-add and time-subtract
are exact and do not decrease HZ below the minimum of their args.
* src/timefns.c (decode_float_time): Don’t signal an error for
floating-point arguments whose base-FLT_RADIX exponent is not less
than DBL_MANT_DIG.  Instead, convert them to (TICKS . 1) values.
Use two (instead of three) integer exponent comparisons in the
typical case.
* test/src/timefns-tests.el (time-arith-tests):
Add more floating-point tests, including some tests
that the old code fails.

1 files changed, 6 insertions, 0 deletions

diff --git a/test/src/timefns-tests.el b/test/src/timefns-tests.el
index a30b2de3a5b..48d964d129c 100644
--- a/test/src/timefns-tests.el
+++ b/test/src/timefns-tests.el
@@ -129,6 +129,12 @@
 			   most-negative-fixnum most-positive-fixnum
 			   (1- most-negative-fixnum)
 			   (1+ most-positive-fixnum)
+			   1e1 -1e1 1e-1 -1e-1
+			   1e8 -1e8 1e-8 -1e-8
+			   1e9 -1e9 1e-9 -1e-9
+			   1e10 -1e10 1e-10 -1e-10
+			   1e16 -1e16 1e-16 -1e-16
+			   1e37 -1e37 1e-37 -1e-37
 			   1e+INF -1e+INF 1e+NaN -1e+NaN
 			   '(0 0 0 1) '(0 0 1 0) '(0 1 0 0) '(1 0 0 0)
 			   '(-1 0 0 0) '(1 2 3 4) '(-1 2 3 4)