GP Fault or Fatal Exception Error on Intel MMX CPU

• Microsoft Windows 95

SYMPTOMS

When you are running a program or using a device driver that calls MMX- specific instructions in the retail release of Windows 95 on a system with an Intel processor supporting the MMX instruction set, the following symptoms may occur:

• A general protection (GP) fault error message
• A fatal exception error message on a blue screen

CAUSE

The retail release of Windows 95 does not properly support some MMX instructions if they are called from a device driver or from program code running in protection level 0 (Ring 0, also known as privileged or Kernel mode). If these instructions are issued while the processor is operating in Ring 0, a GP fault or other serious error may occur.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows 95. An update to address this problem is now available, but is not fully regression tested and should be applied only to computers experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft does not recommend implementing this update at this time. Contact Microsoft Technical Support for additional information about the availability of this update.