1、通过一段MMU的创建来说明MMU的工作方式
下面这段代码是OAL进入kernel Start的一段代码，它也就是wince的页表初始化代码，涉及到两部分内如，分别为二级页表的创建和一级页表的创建。这里的一级页表和前面那个有些不同是TTB发生改变了，也就是说系统进入内核后从新创建了页表。
;-------------------------------------------------------------------------------
; KernelStart - kernel main entry point
;
; The OEM layer will setup any platform or CPU specific configuration that is ; required for the kernel to have access to ROM and DRAM and jump here to start up
; the system. Any processor specific cache or MMU initialization should be completed.
; The MMU and caches should not enabled.
;
; This routine will initialize the first-level page table based up the contents of
; the MemoryMap array and enable the MMU and caches.
;
; NOTE: Until the MMU is enabled, kernel symbolic addresses are not valid and must be
; translated via the MemoryMap array to find the correct physical address.
;
; Entry (r0) = pointer to MemoryMap array in physical memory
; Exit returns if MemoryMap is invalid
;-------------------------------------------------------------------------------
LEAF_ENTRY KernelStart
原作者：jianwen01
