Table 3-7 Second-Level Descriptor Bits; Figure 3-9 Second-Level Descriptor - ARM ARM926EJ-S Technical Reference Manual

ARM DDI0198D
31
Large page base address
Small page base address
Tiny page base address
A second-level descriptor defines a tiny, a small, or a large page descriptor, or is invalid:
• a large page descriptor provides the base address of a 64KB block of memory
• a small page descriptor provides the base address of a 4KB block of memory
• a tiny page descriptor provides the base address of a 1KB block of memory.
Coarse page tables provide base addresses for either small or large pages. Large page
descriptors must be repeated in 16 consecutive entries. Small page descriptors must be
repeated in each consecutive entry.
Fine page tables provide base addresses for large, small, or tiny pages. Large page
descriptors must be repeated in 64 consecutive entries. Small page descriptors must be
repeated in four consecutive entries and tiny page descriptors must be repeated in each
consecutive entry.
Second-level descriptor bit assignments are described in Table 3-7.
Bits
Large Small Tiny
[31:16] [31:12] [31:10]
[15:12] - [9:6]
Copyright © 2001-2003 ARM Limited. All rights reserved.
16 15 12 11 10 9 8 7 6 5 4 3 2 1 0
AP3 AP2 AP1 AP0 C B 0 1
AP3 AP2 AP1 AP0 C B 1 0

Figure 3-9 Second-level descriptor

Table 3-7 Second-level descriptor bits

Description
These bits form the corresponding bits of the physical
address.
Should Be Zero.
Memory Management Unit
Fault
0 0
Large page
Small page
Tiny page
AP C B 1 1
3-15