This is the mail archive of the libstdc++@gcc.gnu.org mailing list for the libstdc++ project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: __intN patch 3/5: main __int128 -> __intN conversion.


On 25/08/14 23:03 -0400, DJ Delorie wrote:

I'd like to see the updated version of the whole of patch 3 (tested
to be actually independent of the other patches) for review, though
I won't be reviewing the C++ parts.

Here it is.  Tested on x86_64.  I include the msp430-modes.def patch
for demonstration purposes although obviously msp430's __int20 won't
work without the other patches.

[snip]

* libstdc++-v3/
	* src/c++11/limits.cc: Add support for __intN types.
	* include/std/type_traits: Likewise.
	* include/std/limits: Likewise.
	* include/c_std/cstdlib: Likewise.
	* include/bits/cpp_type_traits.h: Likewise.
	* include/c_global/cstdlib: Likewise.

These libstdc++ changes are OK for trunk.

Just one question about the include/std/limits changes below.

It seems that __glibcxx_signed_b isn't strictly necessary as it
doesn't use the B argument, so is it just there for consistency?

Index: libstdc++-v3/include/std/limits
===================================================================
--- libstdc++-v3/include/std/limits	(revision 214383)
+++ libstdc++-v3/include/std/limits	(working copy)
@@ -122,27 +122,38 @@
#ifndef __glibcxx_long_double_tinyness_before
#  define __glibcxx_long_double_tinyness_before false
#endif

// You should not need to define any macros below this point.

-#define __glibcxx_signed(T)	((T)(-1) < 0)
+#define __glibcxx_signed_b(T,B)	((T)(-1) < 0)

-#define __glibcxx_min(T) \
-  (__glibcxx_signed (T) ? -__glibcxx_max (T) - 1 : (T)0)
+#define __glibcxx_min_b(T,B)					\
+  (__glibcxx_signed_b (T,B) ? -__glibcxx_max_b (T,B) - 1 : (T)0)

-#define __glibcxx_max(T) \
-  (__glibcxx_signed (T) ? \
-   (((((T)1 << (__glibcxx_digits (T) - 1)) - 1) << 1) + 1) : ~(T)0)
+#define __glibcxx_max_b(T,B)						\
+  (__glibcxx_signed_b (T,B) ?						\
+   (((((T)1 << (__glibcxx_digits_b (T,B) - 1)) - 1) << 1) + 1) : ~(T)0)

-#define __glibcxx_digits(T) \
-  (sizeof(T) * __CHAR_BIT__ - __glibcxx_signed (T))
+#define __glibcxx_digits_b(T,B)				\
+  (B - __glibcxx_signed_b (T,B))

// The fraction 643/2136 approximates log10(2) to 7 significant digits.
+#define __glibcxx_digits10_b(T,B)		\
+  (__glibcxx_digits_b (T,B) * 643L / 2136)
+
+#define __glibcxx_signed(T) \
+  __glibcxx_signed_b (T, sizeof(T) * __CHAR_BIT__)


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]