[U-Boot] [PATCH v7 17/21] bitops: Add fls_long and __ffs64
Fabio Estevam
fabio.estevam at freescale.com
Thu Nov 5 15:43:38 CET 2015
Add fls_long and __ffs64 support to align with the kernel bitops
implementation.
Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
Changes since v6:
- Newly introduced in this series.
- Only touch include/linux/bitops.h after all the arch bitops headers
have been added. This is done to avoid build warnings (Daniel).
include/linux/bitops.h | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 7b4011f..1b2e491 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -2,6 +2,7 @@
#define _LINUX_BITOPS_H
#include <asm/types.h>
+#include <linux/compiler.h>
#define BIT(nr) (1UL << (nr))
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
@@ -139,6 +140,32 @@ static inline unsigned int generic_hweight8(unsigned int w)
# define fls generic_fls
#endif
+static inline unsigned fls_long(unsigned long l)
+{
+ if (sizeof(l) == 4)
+ return fls(l);
+ return fls64(l);
+}
+
+/**
+ * __ffs64 - find first set bit in a 64 bit word
+ * @word: The 64 bit word
+ *
+ * On 64 bit arches this is a synomyn for __ffs
+ * The result is not defined if no bits are set, so check that @word
+ * is non-zero before calling this.
+ */
+static inline unsigned long __ffs64(u64 word)
+{
+#if BITS_PER_LONG == 32
+ if (((u32)word) == 0UL)
+ return __ffs((u32)(word >> 32)) + 32;
+#elif BITS_PER_LONG != 64
+#error BITS_PER_LONG not 32 or 64
+#endif
+ return __ffs((unsigned long)word);
+}
+
/**
* __set_bit - Set a bit in memory
* @nr: the bit to set
--
1.9.1
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