online mmu

MMU, full name: Memory manage unit, Chinese name-memory management unit.Many years ago, when people were still using DOS or older operating systems, the computer's memory was still very small and generally calculated in K units, at that time, the program was not large, so although the memory capacity was small, it could still accommodate the program at that time. However, with the rise of the graphic interface and the increasing demand of users, the s

From: http://hi.baidu.com/ting160/blog/item/419ba1eb1bce7c38adafd574.html MMU: Memory Management Unit *Ing between virtual memory space and physical storage space. Page-based virtual memory management is adopted in arm. It divides the virtual address space into blocks of fixed size, each of which is called a page, and the address space of physical memory is also divided into pages of the same size. The page size can be divided into coarse-grained and

Simulate MMU to design a route table that indexes IPv4 addresses, unlike DxR. I don't know if anyone has played this game. Maybe, maybe not. Time and space are always on the opposite sides. because of incomplete facilities, you can only choose when resources are scarce. However, if the resources are abundant, you can have both the fish and the bear's paw! For route search, the compact data structure occupies a small amount of space. Is it time-consumi

Simulate MMU to design a route table that indexes IPv4 addresses, which is different from DxR and mmudxr.I don't know if anyone has played this game. Maybe, maybe not.Time and space are always on the opposite sides. because of incomplete facilities, you can only choose when resources are scarce. However, if the resources are abundant, you can have both the fish and the bear's paw! For route search, the compact data structure occupies a small amount of

the price for it? If we consider the MMU facility, we will find that the compact data structure saves space and improves speed.Our long-term education is to take righteousness must sacrifice such an education, if not sacrifice, not to be righteous, may also be blackmailed, not blame themselves for being false, because they did not die. In fact, even if the resources are not so abundant, even the resources are scarce, the compact data structure will s

I don't know if anyone has played this way, maybe there is, maybe not.Time and space are always in the favoritism, only because the facilities are not complete, in the age of resource scarcity, can only choose. But if the resources are plentiful, the fish and bear paws can be fully combined! For a routing lookup, the compact data structure takes up a small amount of space, is it going to pay the price for it? If we consider the MMU facility, we will f

I don't know if anyone has played this way, maybe there is, maybe not.Time and space are always in the favoritism, only because the facilities are not complete, in the age of resource scarcity, can only choose. But if the resources are plentiful, the fish and bear paws can be fully combined! For a routing lookup, the compact data structure takes up a small amount of space, is it going to pay the price for it? If we consider the MMU facility, we will f

Category: EmbeddedThe original address: Embedded Linux i line--arm MMU working principle Analysis y307921462First, the creation of the MMU Xu years ago, When people are still using DOS or older operating systems, the computer's memory is very small, usually in K for the calculation, the corresponding, then the program size is not big, so the memory capacity is small, but still can accommodate the progra

Original address: http://www.wowotech.net/linux_kenrel/turn-on-mmu.html First, the preface After a long foreplay, we finally have the time to open MMU, this article mainly describes the code logic before opening MMU and jumping to Start_kernel. After this section completes, we will leave the painful compilation, enters the populace to be loved the C code. Ii. Overview Before and after opening the

Author: wogoyixikexie @ gliet ---------------------------------------------- MMU's name has long been heard, but I have never known how it works. It seems to have been blurred in the last few months. Now it's almost time to finish. In this article, I will cite a lot of English and do not translate it, because I think my English level will misunderstand others. O (∩) O Haha ~ One of the key services provided by an MMU is the ability to manage tasks as

I. Generation of MMU Many years ago, when people were still using DOS or older operating systems, the computer's memory was still very small and generally calculated in K units, at that time, the program was not large, so although the memory capacity was small, it could still accommodate the program at that time. However, with the rise of the graphic interface and the increasing demand of users, the scale of applications also expands, and finally a pr

MMU is short for Memory Management Unit. The Chinese name is the memory management unit. It is the control line used by the central processor (CPU) to manage Virtual Memory and physical memory, it is also responsible for ing virtual addresses to physical addresses and providing hardware-based Memory Access authorization. I. History of MMU Many years ago, when people were still using DOS or older operating s

Virtual Memory Management (vmmemory Management) mechanism is widely used in modern operating systems. This requires the support of MMU (Memory Management Unit) in the processor. This section briefly introduces the role of MMU. First, we introduce two concepts: Virtual Address and physical address. If the processor does not have an MMU, or the

From: http://hi.baidu.com/freewine/blog/item/b0950cad82904d0d4b36d681.html MMU, full name: Memory manage unit, Chinese name-memory management unit. Many years ago, when people were still using DOS or older operating systems, the computer's memory was still very small and generally calculated in K units. Program The size is not big, so although the memory capacity is small, it can still accommodate the current program. However, with the rise of the gr

I have learned the memory management unit MMU of S3C2440 over the past few days. I mainly refer to the full manual for Embedded Linux application development. There are two blogs on the Internet, which are also very detailed. However, they are not well understood in the MMU address translation process. Here, I will explain the content in the embedded Linux application development full manual according to my

Source: http://blog.csdn.net/embeddedfly/article/details/6150452 Detailed analysis of MMU setting process in ce5.0-eboot Assembly startup. s The following is the startup code of the smdk Development Board startup. S.;------------------------------------------------------------------------------- Memorymap equ 0x2a4Bank_size equ 0x00100000; 1 MB per bank in memorymap ArrayBank_shift equ 20 ; Define Ram space for the page tables:;Phybase equ 0x3000000

The memory management unit MMU is responsible for ing virtual addresses to physical addresses, and provides a hardware mechanism for memory access permission check. Four types of ing lengths: segment (1 MB), large page (64 KB), small page (4 kb), and extremely small page (1 kb ). You can set access permissions for each segment. Each subpage (sub-page, that is, 1/4 of the mapped page) of a large page or a small page can be set with access permissions.

26. Core initialization close MMU and cacheLook at the arm storage System below:You can see that the fastest is the processor and the internal registers, their number is very small, the price is very expensive. followed by the TCM tightly coupled memory: cache and main memory. The slowest is the external storage media: Flash and SD card.CACHE:The above is two kinds of mechanisms to be accessed, one is the processor directly to the main memory, the oth

void *from, unsigned long N) { if (Access_ok (Verify_write, to, N)) n = __copy_to_user (to, from, N); return n; } These two functions from the structure of analysis, in fact, can be divided into two parts: 1, first check the user space address pointer is valid (difficulty) 2, call __copy_from_user and __copy_to_user function in this analysis, we first easy later difficult. First look at the __copy_from_user and __copy_to_user functions of the specific data copy function for the ARM

Where is the page table in memory? The OS is the clearest, and the MMU should be clear. The linear address is in the Addressing page table, the linear address is also generated by the OS, and then the CPU passes this linear address to the MMU, because the linear address can be computed by calculating the index in the collection of the page table, thus addressing the page table. The