Intel 253668-032US User Manual

5-46   Vol. 3

PROTECTION

If execute disable bit capability is not enabled or not available, reserved bit checking 
in 64-bit mode includes bit 63 and additional bits. This and reserved bit checking for 
legacy 32-bit paging modes are shown in Table 5-10.
 

Table 5-8.  IA-32e Mode Page Level Protection Matrix with Execute-Disable Bit 

Capability Enabled 

Mode

Paging Mode

Check Bits

32-bit

4-KByte paging (non-PAE)

No reserved bits checked

PSE36 - PDE, 4-MByte page

Bit [21] 

PSE36 - PDE, 4-KByte page

No reserved bits checked

PSE36 - PTE

No reserved bits checked

PAE - PDP table entry

Bits [63:MAXPHYADDR] & [8:5] & [2:1] *

PAE - PDE, 2-MByte page

Bits [62:MAXPHYADDR] & [20:13] *

PAE - PDE, 4-KByte page

Bits [62:MAXPHYADDR] *

PAE - PTE

Bits [62:MAXPHYADDR] *

64-bit

PML4E

Bits [51:MAXPHYADDR] *

PDPTE

Bits [51:MAXPHYADDR] *

PDE, 2-MByte page

Bits [51:MAXPHYADDR] & [20:13] *

PDE, 4-KByte page

Bits [51:MAXPHYADDR] *

PTE

Bits [51:MAXPHYADDR] *

NOTES:

* MAXPHYADDR is the maximum physical address size and is indicated by 

CPUID.80000008H:EAX[bits 7-0].