[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>
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@ -7,7 +7,7 @@
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2001 - 2005 Tensilica Inc.
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* Copyright (C) 2001 - 2007 Tensilica Inc.
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*/
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#ifndef _XTENSA_BITOPS_H
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@ -31,64 +31,44 @@
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#if XCHAL_HAVE_NSA
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static __inline__ int __cntlz (unsigned long x)
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static inline unsigned long __cntlz (unsigned long x)
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{
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int lz;
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asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
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return 31 - lz;
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return lz;
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}
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#else
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static __inline__ int __cntlz (unsigned long x)
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{
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unsigned long sum, x1, x2, x4, x8, x16;
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x1 = x & 0xAAAAAAAA;
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x2 = x & 0xCCCCCCCC;
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x4 = x & 0xF0F0F0F0;
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x8 = x & 0xFF00FF00;
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x16 = x & 0xFFFF0000;
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sum = x2 ? 2 : 0;
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sum += (x16 != 0) * 16;
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sum += (x8 != 0) * 8;
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sum += (x4 != 0) * 4;
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sum += (x1 != 0);
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return sum;
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}
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#endif
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/*
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* ffz: Find first zero in word. Undefined if no zero exists.
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* bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
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*/
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static __inline__ int ffz(unsigned long x)
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static inline int ffz(unsigned long x)
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{
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if ((x = ~x) == 0)
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return 32;
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return __cntlz(x & -x);
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return 31 - __cntlz(~x & -~x);
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}
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/*
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* __ffs: Find first bit set in word. Return 0 for bit 0
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*/
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static __inline__ int __ffs(unsigned long x)
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static inline int __ffs(unsigned long x)
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{
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return __cntlz(x & -x);
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return 31 - __cntlz(x & -x);
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}
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#ifdef __KERNEL__
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/*
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* ffs: Find first bit set in word. This is defined the same way as
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* the libc and compiler builtin ffs routines, therefore
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* differs in spirit from the above ffz (man ffs).
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*/
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static __inline__ int ffs(unsigned long x)
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static inline int ffs(unsigned long x)
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{
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return __cntlz(x & -x) + 1;
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return 32 - __cntlz(x & -x);
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}
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/*
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@ -96,10 +76,22 @@ static __inline__ int ffs(unsigned long x)
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static __inline__ int fls (unsigned int x)
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static inline int fls (unsigned int x)
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{
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return __cntlz(x);
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return 32 - __cntlz(x);
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}
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#else
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/* Use the generic implementation if we don't have the nsa/nsau instructions. */
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# include <asm-generic/bitops/ffs.h>
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# include <asm-generic/bitops/__ffs.h>
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# include <asm-generic/bitops/ffz.h>
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# include <asm-generic/bitops/fls.h>
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#endif
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#include <asm-generic/bitops/fls64.h>
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#include <asm-generic/bitops/find.h>
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#include <asm-generic/bitops/ext2-non-atomic.h>
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