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).

diff --git a/ChangeLog b/ChangeLog
index b5cf37685785a5c2b763266b4e2064cf6b5b2caa..a970b584ca9c77fa2dcd145ea9f40b562762c40e 100644 (file)
--- 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 5144987708dd0720408397e42eeb37ac313b8c55..652a0f2d4a9b820a5012f8b46c8840d0bfcc8f4d 100644 (file)
--- 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