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authorPaul Eggert <eggert@cs.ucla.edu>2012-03-16 03:00:48 -0700
committerPaul Eggert <eggert@cs.ucla.edu>2012-05-23 14:36:24 -0700
commit68605433483b08e8a31541d833bf92ff3ecad75c (patch)
tree393f517cda29f215bd11cde8204be5c7f8049ce4
parent03cf7fe31be5964707a54ed82969b9c181f8dd99 (diff)
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mktime: remove incorrect attempt at unusual arithmetics
* time/mktime.c (TYPE_ONES_COMPLEMENT, TYPE_SIGNED_MAGNITUDE): Remove. The code didn't really work on such machines anyway. (TYPE_MINIMUM): Assume two's complement. (twos_complement_arithmetic): Verify that long_int and time_t are two's complement (or unsigned, in the latter case).
-rw-r--r--ChangeLog7
-rw-r--r--time/mktime.c15
2 files changed, 13 insertions, 9 deletions
diff --git a/ChangeLog b/ChangeLog
index b5cf376857..a970b584ca 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2012-05-23 Paul Eggert <eggert@cs.ucla.edu>
+ mktime: remove incorrect attempt at unusual arithmetics
+ * time/mktime.c (TYPE_ONES_COMPLEMENT, TYPE_SIGNED_MAGNITUDE): Remove.
+ The code didn't really work on such machines anyway.
+ (TYPE_MINIMUM): Assume two's complement.
+ (twos_complement_arithmetic): Verify that long_int and time_t
+ are two's complement (or unsigned, in the latter case).
+
mktime: check signed shifts on long_int and time_t, too
* time/mktime.c (SHR): Check that shifts work as desired
on the types long_int and time_t too, as SHR is used on
diff --git a/time/mktime.c b/time/mktime.c
index 5144987708..652a0f2d4a 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -104,12 +104,8 @@ verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
/* True if negative values of the signed integer type T use two's
- complement, ones' complement, or signed magnitude representation,
- respectively. Much GNU code assumes two's complement, but some
- people like to be portable to all possible C hosts. */
+ complement, or if T is an unsigned integer type. */
#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
-#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
-#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
/* True if the arithmetic type T is signed. */
#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
@@ -121,9 +117,7 @@ verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
#define TYPE_MINIMUM(t) \
((t) (! TYPE_SIGNED (t) \
? (t) 0 \
- : TYPE_SIGNED_MAGNITUDE (t) \
- ? ~ (t) 0 \
- : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
+ : ~ TYPE_MAXIMUM (t)))
#define TYPE_MAXIMUM(t) \
((t) (! TYPE_SIGNED (t) \
? (t) -1 \
@@ -138,7 +132,10 @@ verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
#define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1)
verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));
-verify (twos_complement_arithmetic, TYPE_TWOS_COMPLEMENT (int));
+verify (twos_complement_arithmetic,
+ (TYPE_TWOS_COMPLEMENT (int)
+ && TYPE_TWOS_COMPLEMENT (long_int)
+ && TYPE_TWOS_COMPLEMENT (time_t)));
#define EPOCH_YEAR 1970
#define TM_YEAR_BASE 1900