Intel 64 and IA-32 Architectures Software Developers Manual Volume 3A, System Programming Guide, Part 1

4-46 Vol. 3A
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 4-10.
Table 4-9. 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 [63:40] & [8:5] & [2:1]
1
PAE - PDE, 2-MByte page Bits [62:40] & [20:13]
1
PAE - PDE, 4-KByte page Bits [62:40]
1
PAE - PTE Bits [62:40]
1
64-bit PML4E Bits [51:40]
PDPTE Bits [51:40]
PDE, 2-MByte page Bits [51:40] & [20:13]
PDE, 4-KByte page Bits [51:40]
PTE Bits [51:40]
NOTE:
1. Reserved bit checking also applies to bits 39:36 for processors that support only 36-bits of
physical address. For processor that support only 32 bits of physical address, reserved bit
checking also applies to bits 39:32.