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authorChris Zankel <chris@zankel.net>2007-05-31 17:41:14 -0700
committerChris Zankel <chris@zankel.net>2007-05-31 17:41:14 -0700
commitef6051a90e2ad1af636e99d1d4603fdcf2adfcbe (patch)
treeac64477663d0163161f3646cda4e5dd0c1e21893 /include/asm-xtensa
parent3f0a6766e0cc5a577805732e5adb50a585c58175 (diff)
[XTENSA] fix bit operations in bitops.h
A macro used internally in the bitops.h file to identify the number of leading zeros (__cntlz) was implemented incorrectly for Xtensa processors that don't provide the 'nsa/nsau' instructions. As a result, the dependent functions and macros (ffs, ffz, fls) were broken. Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'include/asm-xtensa')
-rw-r--r--include/asm-xtensa/bitops.h60
1 files changed, 26 insertions, 34 deletions
diff --git a/include/asm-xtensa/bitops.h b/include/asm-xtensa/bitops.h
index d815649617a..96303dff3ee 100644
--- a/include/asm-xtensa/bitops.h
+++ b/include/asm-xtensa/bitops.h
@@ -7,7 +7,7 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
- * Copyright (C) 2001 - 2005 Tensilica Inc.
+ * Copyright (C) 2001 - 2007 Tensilica Inc.
*/
#ifndef _XTENSA_BITOPS_H
@@ -31,64 +31,44 @@
#if XCHAL_HAVE_NSA
-static __inline__ int __cntlz (unsigned long x)
+static inline unsigned long __cntlz (unsigned long x)
{
int lz;
asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
- return 31 - lz;
+ return lz;
}
-#else
-
-static __inline__ int __cntlz (unsigned long x)
-{
- unsigned long sum, x1, x2, x4, x8, x16;
- x1 = x & 0xAAAAAAAA;
- x2 = x & 0xCCCCCCCC;
- x4 = x & 0xF0F0F0F0;
- x8 = x & 0xFF00FF00;
- x16 = x & 0xFFFF0000;
- sum = x2 ? 2 : 0;
- sum += (x16 != 0) * 16;
- sum += (x8 != 0) * 8;
- sum += (x4 != 0) * 4;
- sum += (x1 != 0);
-
- return sum;
-}
-
-#endif
-
/*
* ffz: Find first zero in word. Undefined if no zero exists.
* bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
*/
-static __inline__ int ffz(unsigned long x)
+static inline int ffz(unsigned long x)
{
- if ((x = ~x) == 0)
- return 32;
- return __cntlz(x & -x);
+ return 31 - __cntlz(~x & -~x);
}
/*
* __ffs: Find first bit set in word. Return 0 for bit 0
*/
-static __inline__ int __ffs(unsigned long x)
+static inline int __ffs(unsigned long x)
{
- return __cntlz(x & -x);
+ return 31 - __cntlz(x & -x);
}
+
+#ifdef __KERNEL__
+
/*
* ffs: Find first bit set in word. This is defined the same way as
* the libc and compiler builtin ffs routines, therefore
* differs in spirit from the above ffz (man ffs).
*/
-static __inline__ int ffs(unsigned long x)
+static inline int ffs(unsigned long x)
{
- return __cntlz(x & -x) + 1;
+ return 32 - __cntlz(x & -x);
}
/*
@@ -96,10 +76,22 @@ static __inline__ int ffs(unsigned long x)
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*/
-static __inline__ int fls (unsigned int x)
+static inline int fls (unsigned int x)
{
- return __cntlz(x);
+ return 32 - __cntlz(x);
}
+
+#else
+
+/* Use the generic implementation if we don't have the nsa/nsau instructions. */
+
+# include <asm-generic/bitops/ffs.h>
+# include <asm-generic/bitops/__ffs.h>
+# include <asm-generic/bitops/ffz.h>
+# include <asm-generic/bitops/fls.h>
+
+#endif
+
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/find.h>
#include <asm-generic/bitops/ext2-non-atomic.h>