Author: jhb
Date: Fri Mar 20 10:27:06 2015
New Revision: 280279
URL: https://svnweb.freebsd.org/changeset/base/280279
Log:
Expand the bitcount* API to support 64-bit integers, plain ints and longs
and create a "hidden" API that can be used in other system headers without
adding namespace pollution.
- If the POPCNT instruction is enabled at compile time, use
__builtin_popcount*() to implement __bitcount*(), otherwise fall back
to software implementations.
- Use the existing bitcount16() and bitcount32() from <sys/systm.h> to
implement the non-POPCNT __bitcount16() and __bitcount32() in
<sys/types.h>.
- For the non-POPCNT __bitcount64(), use a similar SWAR method on 64-bit
systems. For 32-bit systems, use two __bitcount32() operations on the
two halves.
- Use __bitcount32() to provide a __bitcount() that operates on plain ints.
- Use either __bitcount32() or __bitcount64() to provide a
__bitcountl() that operates on longs.
- Add public bitcount*() wrappers for __bitcount*() for use in the kernel
in <sys/libkern.h>.
- Use __builtinl() instead of __builtin_popcountl() in BIT_COUNT().
Discussed with: bde
Modified:
head/sys/sys/bitset.h
head/sys/sys/libkern.h
head/sys/sys/systm.h
head/sys/sys/types.h
Modified: head/sys/sys/bitset.h
==============================================================================
--- head/sys/sys/bitset.h Fri Mar 20 10:15:34 2015 (r280278)
+++ head/sys/sys/bitset.h Fri Mar 20 10:27:06 2015 (r280279)
@@ -182,7 +182,7 @@
\
__count = 0; \
for (__i = 0; __i < __bitset_words((_s)); __i++) \
- __count += __builtin_popcountl((p)->__bits[__i]); \
+ __count += __bitcountl((p)->__bits[__i]); \
__count; \
})
Modified: head/sys/sys/libkern.h
==============================================================================
--- head/sys/sys/libkern.h Fri Mar 20 10:15:34 2015 (r280278)
+++ head/sys/sys/libkern.h Fri Mar 20 10:27:06 2015 (r280279)
@@ -98,6 +98,11 @@ int flsl(long);
#ifndef HAVE_INLINE_FLSLL
int flsll(long long);
#endif
+#define bitcount64(x) __bitcount64((uint64_t)(x))
+#define bitcount32(x) __bitcount32((uint32_t)(x))
+#define bitcount16(x) __bitcount16((uint16_t)(x))
+#define bitcountl(x) __bitcountl((u_long)(x))
+#define bitcount(x) __bitcount((u_int)(x))
int fnmatch(const char *, const char *, int);
int locc(int, char *, u_int);
Modified: head/sys/sys/systm.h
==============================================================================
--- head/sys/sys/systm.h Fri Mar 20 10:15:34 2015 (r280278)
+++ head/sys/sys/systm.h Fri Mar 20 10:27:06 2015 (r280279)
@@ -428,33 +428,6 @@ int alloc_unr_specific(struct unrhdr *uh
int alloc_unrl(struct unrhdr *uh);
void free_unr(struct unrhdr *uh, u_int item);
-/*
- * Population count algorithm using SWAR approach
- * - "SIMD Within A Register".
- */
-static __inline uint32_t
-bitcount32(uint32_t x)
-{
-
- x = (x & 0x55555555) + ((x & 0xaaaaaaaa) >> 1);
- x = (x & 0x33333333) + ((x & 0xcccccccc) >> 2);
- x = (x + (x >> 4)) & 0x0f0f0f0f;
- x = (x + (x >> 8));
- x = (x + (x >> 16)) & 0x000000ff;
- return (x);
-}
-
-static __inline uint16_t
-bitcount16(uint32_t x)
-{
-
- x = (x & 0x5555) + ((x & 0xaaaa) >> 1);
- x = (x & 0x3333) + ((x & 0xcccc) >> 2);
- x = (x + (x >> 4)) & 0x0f0f;
- x = (x + (x >> 8)) & 0x00ff;
- return (x);
-}
-
void intr_prof_stack_use(struct thread *td, struct trapframe *frame);
#endif /* !_SYS_SYSTM_H_ */
Modified: head/sys/sys/types.h
==============================================================================
--- head/sys/sys/types.h Fri Mar 20 10:15:34 2015 (r280278)
+++ head/sys/sys/types.h Fri Mar 20 10:27:06 2015 (r280279)
@@ -294,6 +294,68 @@ typedef _Bool bool;
#include <sys/select.h>
+#ifdef __POPCNT__
+#define __bitcount64(x) __builtin_popcountll((__uint64_t)(x))
+#define __bitcount32(x) __builtin_popcount((__uint32_t)(x))
+#define __bitcount16(x) __builtin_popcount((__uint16_t)(x))
+#define __bitcountl(x) __builtin_popcountl((unsigned long)(x))
+#define __bitcount(x) __builtin_popcount((unsigned int)(x))
+#else
+/*
+ * Population count algorithm using SWAR approach
+ * - "SIMD Within A Register".
+ */
+static __inline __uint16_t
+__bitcount16(__uint16_t _x)
+{
+
+ _x = (_x & 0x5555) + ((_x & 0xaaaa) >> 1);
+ _x = (_x & 0x3333) + ((_x & 0xcccc) >> 2);
+ _x = (_x + (_x >> 4)) & 0x0f0f;
+ _x = (_x + (_x >> 8)) & 0x00ff;
+ return (_x);
+}
+
+static __inline __uint32_t
+__bitcount32(__uint32_t _x)
+{
+
+ _x = (_x & 0x55555555) + ((_x & 0xaaaaaaaa) >> 1);
+ _x = (_x & 0x33333333) + ((_x & 0xcccccccc) >> 2);
+ _x = (_x + (_x >> 4)) & 0x0f0f0f0f;
+ _x = (_x + (_x >> 8));
+ _x = (_x + (_x >> 16)) & 0x000000ff;
+ return (_x);
+}
+
+#ifdef __LP64__
+static __inline __uint64_t
+__bitcount64(__uint64_t _x)
+{
+
+ _x = (_x & 0x5555555555555555) + ((_x & 0xaaaaaaaaaaaaaaaa) >> 1);
+ _x = (_x & 0x3333333333333333) + ((_x & 0xcccccccccccccccc) >> 2);
+ _x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0f;
+ _x = (_x + (_x >> 8));
+ _x = (_x + (_x >> 16));
+ _x = (_x + (_x >> 32)) & 0x000000ff;
+ return (_x);
+}
+
+#define __bitcountl(x) __bitcount64((unsigned long)(x))
+#else
+static __inline __uint64_t
+__bitcount64(__uint64_t _x)
+{
+
+ return (__bitcount32(_x >> 32) + __bitcount32(_x));
+}
+
+#define __bitcountl(x) __bitcount32((unsigned long)(x))
+#endif
+#define __bitcount(x) __bitcount32((unsigned int)(x))
+#endif
+
/*
* minor() gives a cookie instead of an index since we don't want to
* change the meanings of bits 0-15 or waste time and space shifting
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