svn commit: r306319 - head/sys/i386/i386

[Colin Percival]

On 09/25/16 23:53, Bruce Evans wrote:
> On Sun, 25 Sep 2016, Colin Percival wrote:
>> On 09/25/16 11:39, Bruce Evans wrote:
>>> Author: bde
>>> Date: Sun Sep 25 18:39:24 2016
>>> New Revision: 306319
>>> URL: https://svnweb.freebsd.org/changeset/base/306319
>>>
>>> Log:
>>>   Minor fixes for 160-bit disassembly:
>>
>> I thought the x86 architecture was limited to 120-bit instructions?
> 
> Oops.
> 
> Is 120 the exact limit on instruction length is is that just for prefixes?
> I think the instruction fetch pipeline was 16 bytes, but it is now often
> 32 or 64.

Traditionally x86 CPUs would generate an invalid-opcode fault if redundant
instruction prefixes resulted in an instruction exceeding 15 bytes.  This
behaviour might have changed in the past two decades, but I doubt it.

-- 
Colin Percival
Security Officer Emeritus, FreeBSD | The power to serve
Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid