On Wed, Dec 11, 2013 at 10:54:00AM -0800, Jarno Rajahalme wrote:
> util.h declares this when needed, make sure the definition is compiled
> in only in that case.
>
> Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com>
With this, I still get:
../lib/util.c:921:15: warning: symbol 'count_1bits_8' was not declared.
Should it be static?
because the previous declaration of count_1bits_8[] is not in scope at
the point of definition in util.c.
How about something like this? (Not tested outside of 32-bit without
__POPCNT__.)
diff --git a/lib/util.c b/lib/util.c
index 13d41a7..000504c 100644
--- a/lib/util.c
+++ b/lib/util.c
@@ -901,7 +901,7 @@ raw_clz64(uint64_t n)
}
#endif
-#if !(__GNUC__ >= 4 && defined(__corei7))
+#if NEED_COUNT_1BITS_8
#define INIT1(X) \
((((X) & (1 << 0)) != 0) + \
(((X) & (1 << 1)) != 0) + \
diff --git a/lib/util.h b/lib/util.h
index 8d810c2..b158c2f 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -371,49 +371,55 @@ log_2_ceil(uint64_t n)
return log_2_floor(n) + !is_pow2(n);
}
-extern const uint8_t count_1bits_8[256];
-
-/* Returns the number of 1-bits in 'x', between 0 and 32 inclusive. */
+/* unsigned int count_1bits(uint64_t x):
+ *
+ * Returns the number of 1-bits in 'x', between 0 and 64 inclusive. */
+#if UINTPTR_MAX == UINT64_MAX
+static inline unsigned int
+count_1bits(uint64_t x)
+{
+#if __GNUC__ >= 4 && __POPCNT__
+ return __builtin_popcountll(x);
+#else
+ /* This portable implementation is the fastest one we know of for 64
+ * bits, and about 3x faster than GCC 4.7 __builtin_popcountll(). */
+ const uint64_t h55 = UINT64_C(0x5555555555555555);
+ const uint64_t h33 = UINT64_C(0x3333333333333333);
+ const uint64_t h0F = UINT64_C(0x0F0F0F0F0F0F0F0F);
+ const uint64_t h01 = UINT64_C(0x0101010101010101);
+ x -= (x >> 1) & h55; /* Count of each 2 bits in-place. */
+ x = (x & h33) + ((x >> 2) & h33); /* Count of each 4 bits in-place. */
+ x = (x + (x >> 4)) & h0F; /* Count of each 8 bits in-place. */
+ return (x * h01) >> 56; /* Sum of all bytes. */
+#endif
+}
+#else /* not 64-bit */
+#if __GNUC__ >= 4 && __POPCNT__
static inline unsigned int
count_1bits_32(uint32_t x)
{
-#if __GNUC__ >= 4 && defined(__corei7)
- /* __builtin_popcount() is fast only when supported by the CPU. */
return __builtin_popcount(x);
+}
#else
+#define NEED_COUNT_1BITS_8 1
+extern const uint8_t count_1bits_8[256];
+static inline unsigned int
+count_1bits_32(uint32_t x)
+{
/* This portable implementation is the fastest one we know of for 32 bits,
* and faster than GCC __builtin_popcount(). */
return (count_1bits_8[x & 0xff] +
count_1bits_8[(x >> 8) & 0xff] +
count_1bits_8[(x >> 16) & 0xff] +
count_1bits_8[x >> 24]);
-#endif
}
-
-/* Returns the number of 1-bits in 'x', between 0 and 64 inclusive. */
+#endif
static inline unsigned int
count_1bits(uint64_t x)
{
- if (sizeof(void *) == 8) { /* 64-bit CPU */
-#if __GNUC__ >= 4 && defined(__corei7)
- /* __builtin_popcountll() is fast only when supported by the CPU. */
- return __builtin_popcountll(x);
-#else
- /* This portable implementation is the fastest one we know of for 64
- * bits, and about 3x faster than GCC 4.7 __builtin_popcountll(). */
- const uint64_t h55 = UINT64_C(0x5555555555555555);
- const uint64_t h33 = UINT64_C(0x3333333333333333);
- const uint64_t h0F = UINT64_C(0x0F0F0F0F0F0F0F0F);
- const uint64_t h01 = UINT64_C(0x0101010101010101);
- x -= (x >> 1) & h55; /* Count of each 2 bits in-place. */
- x = (x & h33) + ((x >> 2) & h33); /* Count of each 4 bits in-place. */
- x = (x + (x >> 4)) & h0F; /* Count of each 8 bits in-place. */
- return (x * h01) >> 56; /* Sum of all bytes. */
-#endif
- } else { /* 32-bit CPU */
- return count_1bits_32(x) + count_1bits_32(x >> 32);
- }
+ return count_1bits_32(x) + count_1bits_32(x >> 32);
}
+#endif
/* Returns the rightmost 1-bit in 'x' (e.g. 01011000 => 00001000), or 0 if 'x'
* is 0. */
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