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Date: Fri, 28 Mar 2008 04:51:10 +0100 From: Arnd Bergmann <arnd@...db.de> To: Bob Copeland <me@...copeland.com> Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org Subject: Re: [PATCH 5/7] omfs: add bitmap routines On Thursday 27 March 2008, Bob Copeland wrote: > +static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; > + > +unsigned long omfs_count_free(struct super_block *sb) > +{ > + unsigned int i, j, count = 0; > + unsigned char *map; > + unsigned long sum = 0; > + struct omfs_sb_info *sbi = OMFS_SB(sb); > + > + for (i = 0; i < sbi->s_imap_size; i++) { > + map = (unsigned char *) sbi->s_imap[i]; > + for (j = 0; j < sb->s_blocksize && > + count + j < sbi->s_num_blocks/8; j++) > + sum += nibblemap[map[j] & 0xf] + > + nibblemap[(map[j] >> 4) & 0xf]; > + count += sb->s_blocksize; > + } > + return sum; > +} I think it would be helpful to express this using hweight64. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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