On Sun, 2002-11-03 at 18:17, Denis Vlasenko wrote:
Jump target 17e0 is aligned (with nops):
> 17dd: 88 02 mov %al,(%edx)
> 17df: 90 nop =20
> 17e0: 89 d0 mov %edx,%eax
> 17e2: 5a pop %edx
> 17ec: eb f2 jmp 17e0 <__constant_memcpy+0x20>
> 17fa: eb e4 jmp 17e0 <__constant_memcpy+0x20>
> 1800: eb de jmp 17e0 <__constant_memcpy+0x20>
> 187c: e9 5f ff ff ff jmp 17e0 <__constant_memcpy+0x20>
> 1881: eb 0d jmp 1890 <__constant_memcpy+0xd0>
> 1883: 90 nop =20
...
> 188f: 90 nop =20
> 1890: c1 e9 02 shr $0x2,%ecx
> 1893: 89 d7 mov %edx,%edi
And also jump target 1890 is aligned.
I think the penalty of few NOPs is smaller than result of jump to
unaligned address. This is especially true with P4 architecture.
- Jussi Laako
--=-3Nma7VigEoahCgwnoAxG
Content-Type: application/pgp-signature; name=signature.asc
Content-Description: This is a digitally signed message part
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.7 (GNU/Linux)
iD8DBQA9xUwvS3txJU4L5RQRAtD9AJ4npxAiIK3d5e6Cq/VduKswbeC4OACdGrdt
FLJXVrjpxawp9TH3m6UP3RU=
=S8Av
-----END PGP SIGNATURE-----
--=-3Nma7VigEoahCgwnoAxG--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/