PERFORCE change 41515 for review

[Peter Wemm]

http://perforce.freebsd.org/chv.cgi?CH=41515

Change 41515 by peter at peter_daintree on 2003/11/05 17:42:24

	sync with vendor branch (mismerge)

Affected files ...

.. //depot/projects/hammer/sys/amd64/amd64/mp_machdep.c#22 edit

Differences ...

==== //depot/projects/hammer/sys/amd64/amd64/mp_machdep.c#22 (text+ko) ====

@@ -24,7 +24,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/sys/i386/i386/mp_machdep.c,v 1.220 2003/11/03 22:32:03 jhb Exp $");
+__FBSDID("$FreeBSD: src/sys/i386/i386/mp_machdep.c,v 1.221 2003/11/06 01:24:25 peter Exp $");
 
 #include "opt_cpu.h"
 #include "opt_kstack_pages.h"
@@ -744,6 +744,12 @@
  * -mcpu=pentiumpro and -march=pentiumpro then gcc-3.1 will use
  * an imull, and in that case it is faster.  In most other cases
  * it appears slightly slower.
+ *
+ * Another variant (also from fortune):
+ * #define BITCOUNT(x) (((BX_(x)+(BX_(x)>>4)) & 0x0F0F0F0F) % 255)
+ * #define  BX_(x)     ((x) - (((x)>>1)&0x77777777)            \
+ *                          - (((x)>>2)&0x33333333)            \
+ *                          - (((x)>>3)&0x11111111))
  */
 static __inline u_int32_t
 popcnt(u_int32_t m)