IRIX long-double sqrt(2) one bit error in the least significant end.

[perl5.git] / handy.h

diff --git a/handy.h b/handy.h
index c3fd77d..ffb8e2f 100644 (file)
--- a/handy.h
+++ b/handy.h
@@ -962,14 +962,23 @@ patched there.  The file as of this writing is cpan/Devel-PPPort/parts/inc/misc
 #  define _CC_NON_FINAL_FOLD           21
 #  define _CC_IS_IN_SOME_FOLD          22
 #  define _CC_MNEMONIC_CNTRL           23
-/* Unused: 24-31
+
+/* This next group is only used on EBCDIC platforms, so theoretically could be
+ * shared with something entirely different that's only on ASCII platforms */
+#  define _CC_UTF8_START_BYTE_IS_FOR_AT_LEAST_SURROGATE 28
+#  define _CC_UTF8_IS_START                             29
+#  define _CC_UTF8_IS_DOWNGRADEABLE_START               30
+#  define _CC_UTF8_IS_CONTINUATION                      31
+/* Unused: 24-27
  * If more bits are needed, one could add a second word for non-64bit
  * QUAD_IS_INT systems, using some #ifdefs to distinguish between having a 2nd
  * word or not.  The IS_IN_SOME_FOLD bit is the most easily expendable, as it
  * is used only for optimization (as of this writing), and differs in the
  * Latin1 range from the ALPHA bit only in two relatively unimportant
  * characters: the masculine and feminine ordinal indicators, so removing it
- * would just cause /i regexes which match them to run less efficiently */
+ * would just cause /i regexes which match them to run less efficiently.
+ * Similarly the EBCDIC-only bits are used just for speed, and could be
+ * replaced by other means */
 
 #if defined(PERL_CORE) || defined(PERL_EXT)
 /* An enum version of the character class numbers, to help compilers
@@ -1908,10 +1917,13 @@ PoisonWith(0xEF) for catching access to freed memory.
  * As well as avoiding the need for a run-time check in some cases, it's
  * designed to avoid compiler warnings like:
  *     comparison is always false due to limited range of data type
+ * It's mathematically equivalent to
+ *    max(n) * sizeof(t) > MEM_SIZE_MAX
  */
 
 #  define _MEM_WRAP_NEEDS_RUNTIME_CHECK(n,t) \
-    (sizeof(t) > ((MEM_SIZE)1 << 8*(sizeof(MEM_SIZE) - sizeof(n))))
+    (  sizeof(MEM_SIZE) < sizeof(n) \
+    || sizeof(t) > ((MEM_SIZE)1 << 8*(sizeof(MEM_SIZE) - sizeof(n))))
 
 /* This is written in a slightly odd way to avoid various spurious
  * compiler warnings. We *want* to write the expression as