[PTLsim-devel] Bug with LOCK prefix

Tue Jun 19 13:14:25 EDT 2007

Hi again,
  there seems to be a bug in PTLsim regarding the use of the LOCK-prefix:

"AMD64 ArchitectureProgrammer’s Manual Volume 3: General-Purpose and System 
Instructions (24594)", section "1.2.5 Lock Prefix": ".... An invalid-opcode 
exception occurs if the LOCK prefix is used with any other instruction."

PTLsim, however, simply ignores the LOCK prefix in most (if not all) of those 
cases, e.g. arithmetic-ops with two registers, simply search for "prefixes &= 
~PFX_LOCK;"

Actual testing confirms that! Real hardware faults, PTLsim silently ignores.

Thanks,
  Stephan
-- 
Stephan Diestelhorst, AMD Operating System Research Center
stephan.diestelhorst at amd.com, Tel.   (AMD: 8-4903)