X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fcount-one-bits.h;h=fcbe7fda67b967e96f1045c955c083b2a468cdf4;hb=1a2869593e115e4a6c74aaa0b23ca612357403ce;hp=7553bec4ecbfc850f62901ac1fbcf0b96eb99453;hpb=e9cfd9f2d0d75d5d09d0acff6cb578a5c039c45c;p=gnulib.git

diff --git a/lib/count-one-bits.h b/lib/count-one-bits.h
index 7553bec4e..fcbe7fda6 100644
--- a/lib/count-one-bits.h
+++ b/lib/count-one-bits.h
@@ -1,10 +1,10 @@
 /* count-one-bits.h -- counts the number of 1-bits in a word.
-   Copyright (C) 2007 Free Software Foundation, Inc.
+   Copyright (C) 2007-2008 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -12,27 +12,30 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* Written by Ben Pfaff.  */
 
 #ifndef COUNT_ONE_BITS_H
 # define COUNT_ONE_BITS_H 1
 
-#include <limits.h>
 #include <stdlib.h>
 #include "verify.h"
 
-#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR >= 4)
+/* Expand the code which computes the number of 1-bits of the local
+   variable 'x' of type TYPE (an unsigned integer type) and returns it
+   from the current function.  */
+#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
 #define COUNT_ONE_BITS(BUILTIN, TYPE)              \
         return BUILTIN (x);
 #else
-#define COUNT_ONE_BITS(BUILTIN, TYPE)                           \
-        int count = count_one_bits_32 (x);                      \
-        if (CHAR_BIT * sizeof (TYPE) > 32)                      \
-          count += count_one_bits_32 (x >> 31 >> 1);            \
-        (void) verify_true (CHAR_BIT * sizeof (TYPE) <= 64);    \
+#define COUNT_ONE_BITS(BUILTIN, TYPE)                                       \
+        /* This condition is written so as to avoid shifting by more than   \
+           31 bits at once, and also avoids a random HP-UX cc bug.  */      \
+        verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64 bits */ \
+        int count = count_one_bits_32 (x);                                  \
+        if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */          \
+          count += count_one_bits_32 (x >> 31 >> 1);                        \
         return count;
 
 /* Compute and return the the number of 1-bits set in the least