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Subject[patch 06/13] find bit corner case.
From: Martin Schwidefsky <schwidefsky@de.ibm.com>

Fix [ext2_]find_first_[zero_]bit for the corner case of an all clear
or all set bit field by always handling that last word of the bit field
with __ffz_word/__ffs_word.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
include/asm-s390/bitops.h | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
Index: quilt-2.6/include/asm-s390/bitops.h
===================================================================
--- quilt-2.6.orig/include/asm-s390/bitops.h
+++ quilt-2.6/include/asm-s390/bitops.h
@@ -456,16 +456,18 @@ static inline unsigned long __ffz_word_l

asm volatile(
#ifndef __s390x__
- " ahi %1,31\n"
- " srl %1,5\n"
+ " ahi %1,-1\n"
+ " sra %1,5\n"
+ " jz 1f\n"
"0: c %2,0(%0,%3)\n"
" jne 1f\n"
" la %0,4(%0)\n"
" brct %1,0b\n"
"1:\n"
#else
- " aghi %1,63\n"
- " srlg %1,%1,6\n"
+ " aghi %1,-1\n"
+ " srag %1,%1,6\n"
+ " jz 1f\n"
"0: cg %2,0(%0,%3)\n"
" jne 1f\n"
" la %0,8(%0)\n"
@@ -491,16 +493,18 @@ static inline unsigned long __ffs_word_l

asm volatile(
#ifndef __s390x__
- " ahi %1,31\n"
- " srl %1,5\n"
+ " ahi %1,-1\n"
+ " sra %1,5\n"
+ " jz 1f\n"
"0: c %2,0(%0,%3)\n"
" jne 1f\n"
" la %0,4(%0)\n"
" brct %1,0b\n"
"1:\n"
#else
- " aghi %1,63\n"
- " srlg %1,%1,6\n"
+ " aghi %1,-1\n"
+ " srag %1,%1,6\n"
+ " jz 1f\n"
"0: cg %2,0(%0,%3)\n"
" jne 1f\n"
" la %0,8(%0)\n"
--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.



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