Alexander Kuleshov <[email protected]> writes: > static inline unsigned char fat_checksum(const __u8 *name) > { > + u8 i; > unsigned char s = name[0]; > - s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2]; > - s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4]; > - s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6]; > - s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8]; > - s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10]; > + > + for (i = 1; i < 11; i++) > + s = (s << 7) + (s >> 1) + name[i]; > + > return s; > }
When I wrote this, IIRC, there was measurable performance difference. All major gcc versions are enough smart now to optimize this? -- OGAWA Hirofumi <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
