Messages in this thread |  | | | Date | Wed, 23 Nov 2005 12:31:44 -0700 | | From | jmerkey@ns1 ... | | Subject | Re: [patch] SMP alternatives |
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On Wed, Nov 23, 2005 at 11:03:15AM -0800, Linus Torvalds wrote: > > > On Wed, 23 Nov 2005, Jeff V. Merkey wrote: > > > > The lock prefix '0F' is used for a lot of opcodes other than "lock". Go check > > the instruction set reference. > > No it's not. > > 0F is indeed the two-byte prefix. But lock is F0, and it's unique. > > Sometimes Intel re-uses the prefixes for other things eg "rep nop", but I > don't think that has ever happened for the lock prefix. > > Besides, the instructions look very different internally in the CPU after > decoding, and anyway you'd not want to ignore the lock prefix _early_ at > decode time anyway (many instructions turn into illegal instructions with > a lock prefix, as do reg-reg modrm bytes). So you'd dismiss the lock > prefix not at a byte level, but at a minimum just after the decode stage. > > Linus
I always get numbers and words transposed. Thanks for the correction.
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