Enhanced. The GP exception predates the Pentium® processor. Starting with the Pentium® processor, a GP exception occurs when an attempt is made to write a one into a reserved bit position of a special register:
Attempting to write a one into a reserved bit of CR4.
Attempting to write to a reserved bit in an MSR.
If CR4[PSE] = 1 (4MB Paging enabled) and the processor detects that any reserved bits in a PDE =1. These bits are checked during a write to CR0, CR3, or CR4.
Enhanced. The Page Fault exception predates the Pentium® processor. Starting with the Pentium® processor, a Page Fault exception occurs when a one is detected in any of the reserved bits in a PTE or a PDE during linear-to-physical address translation.
New exception. The Pentium® was the first IA32 processor to implement the Machine Check exception. See “Machine Check Exception (18)” on page 324 for a full description.
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