[U-Boot] [PATCH 07/13] x86: bitops: Use the generic bitops headers

Fabio Estevam festevam at gmail.com
Sat Oct 24 14:28:07 CEST 2015


From: Fabio Estevam <fabio.estevam at freescale.com>

Use the generic bitops and also add custom __ffs() implementation
as per the kernel.

Also align the ffs() implementation with the kernel.

Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
 arch/x86/include/asm/bitops.h | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 5a7e4cb..f97dc66 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -14,6 +14,10 @@
  * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
  */
 
+#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
+#include <asm-generic/bitops/fls64.h>
+
 #ifdef CONFIG_SMP
 #define LOCK_PREFIX "lock ; "
 #else
@@ -332,6 +336,20 @@ static __inline__ unsigned long ffz(unsigned long word)
 #ifdef __KERNEL__
 
 /**
+ * __ffs - find first set bit in word
+ * @word: The word to search
+ *
+ * Undefined if no bit exists, so code should check against 0 first.
+ */
+static inline unsigned long __ffs(unsigned long word)
+{
+	__asm__("rep; bsf %1,%0"
+		: "=r" (word)
+		: "rm" (word));
+	return word;
+}
+
+/**
  * ffs - find first bit set
  * @x: the word to search
  *
@@ -346,7 +364,8 @@ static __inline__ int ffs(int x)
 	__asm__("bsfl %1,%0\n\t"
 		"jnz 1f\n\t"
 		"movl $-1,%0\n"
-		"1:" : "=r" (r) : "g" (x));
+		"1:" : "=r" (r) : "rm" (x));
+
 	return r+1;
 }
 #define PLATFORM_FFS
-- 
1.9.1



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