From: Heiko Carstens Date: Thu, 8 Oct 2015 11:51:44 +0000 (+0200) Subject: s390/bitops: remove 31 bit related comments X-Git-Tag: firefly_0821_release~176^2~815^2~31 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=48002bd5af37c3f6ac4a1484427ac52f7f184950;p=firefly-linux-kernel-4.4.55.git s390/bitops: remove 31 bit related comments Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h index 47bd0878a006..8043f10da6b5 100644 --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -11,30 +11,25 @@ * big-endian system because, unlike little endian, the number of each * bit depends on the word size. * - * The bitop functions are defined to work on unsigned longs, so for an - * s390x system the bits end up numbered: + * The bitop functions are defined to work on unsigned longs, so the bits + * end up numbered: * |63..............0|127............64|191...........128|255...........192| - * and on s390: - * |31.....0|63....32|95....64|127...96|159..128|191..160|223..192|255..224| * * There are a few little-endian macros used mostly for filesystem - * bitmaps, these work on similar bit arrays layouts, but - * byte-oriented: + * bitmaps, these work on similar bit array layouts, but byte-oriented: * |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56| * - * The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit - * number field needs to be reversed compared to the big-endian bit - * fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b). + * The main difference is that bit 3-5 in the bit number field needs to be + * reversed compared to the big-endian bit fields. This can be achieved by + * XOR with 0x38. * - * We also have special functions which work with an MSB0 encoding: - * on an s390x system the bits are numbered: + * We also have special functions which work with an MSB0 encoding. + * The bits are numbered: * |0..............63|64............127|128...........191|192...........255| - * and on s390: - * |0.....31|32....63|64....95|96...127|128..159|160..191|192..223|224..255| * - * The main difference is that bit 0-63 (64b) or 0-31 (32b) in the bit - * number field needs to be reversed compared to the LSB0 encoded bit - * fields. This can be achieved by XOR with 0x3f (64b) or 0x1f (32b). + * The main difference is that bit 0-63 in the bit number field needs to be + * reversed compared to the LSB0 encoded bit fields. This can be achieved by + * XOR with 0x3f. * */ @@ -299,10 +294,8 @@ static inline void __clear_bit_unlock(unsigned long nr, /* * Functions which use MSB0 bit numbering. - * On an s390x system the bits are numbered: + * The bits are numbered: * |0..............63|64............127|128...........191|192...........255| - * and on s390: - * |0.....31|32....63|64....95|96...127|128..159|160..191|192..223|224..255| */ unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size); unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size, diff --git a/arch/s390/lib/find.c b/arch/s390/lib/find.c index 922003c1b90d..d90b9245ea41 100644 --- a/arch/s390/lib/find.c +++ b/arch/s390/lib/find.c @@ -1,10 +1,8 @@ /* * MSB0 numbered special bitops handling. * - * On s390x the bits are numbered: + * The bits are numbered: * |0..............63|64............127|128...........191|192...........255| - * and on s390: - * |0.....31|32....63|64....95|96...127|128..159|160..191|192..223|224..255| * * The reason for this bit numbering is the fact that the hardware sets bits * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap