jmp linux

. This amount of displacement is added to the IP register. The displacement amount is a signed number, negative numbers indicate a forward transition, and positive numbers indicate a backward transition. The transfer range is 32768 to +32767.Third, the indirect transfer ①jmp AX (intra-segment register indirect transfer); ②jmp [BX] (Intra-segment memory indirect transfer). Sends the contents of the specified

Linux services)It is important for Linux users. Disabling unnecessary services can make Linux run more efficiently, but not all Linux services can be disabled. After installing centos Linux today, we found that many services were started when

First, interrupt initialization1. Initialization of the interrupt vector table IDTvoid __init Init_irq (void) {int i; #ifndef Config_x86_visws_apicinit_isa_irqs (); #elseinit_VISWS_APIC_irqs (); #endif/* * Cover the whole vector space, no vector can escape * us. (Some of these would be overridden and become * ' special ' SMP interrupts) */for (i = 0; i For interrupt vectors from 0x20 to 224, set the interrupt handler, set_intr_gate as follows:void set_intr_gate (unsigned int n, void *addr) {_set

Tags: System ops LinuxBasic knowledge of computer playing:CPU (operator, Controller), memory, I/O (input device, output device)程序运行模式： 用户空间：user space,us （可执行普通指令） 内核空间：system space （可执行特权指令）POS：Postable Operating System 可移植操作系统 POSIX 可移植操作系统规范运行程序格式：Windows：EXE，库文件dll（dynamic link library 动态链接库）Linux：ELF，库文件so（shared object 共享对象）程序：指令+数据 指令：只读 数据：读写程序：算法+数据结构库调用，系统调用：允许被调用的程序；malloc() 申请内存空间；free() 释放内存空间；编程语言 汇编语言：微码编程（系统级程序员） 系统中某些于硬件相关的特有代码、驱动程序开发； 高级语言：C、C++

Linux-(2) Basic file operations in Linux, linux-linux In linux, everything is files, directories are files, and hardware is files. Therefore, basic file operations are especially important. 1. List the contents of the directory: Ls Parameters: -A: displays all files (includ

Logout Exit SystemGedit Text Editor ToolsUname–r View kernel version information, uname–a more detailsCat/proc/cpuinfo viewing CPUsCat/proc/meminfo Viewing memoryHostname Viewing host namesIfconfig eth0 view eth0 IP AddressAlias ls= ' ls–ll ' setting aliasesTo view the path of the current terminal: TTYView current Shell:echo $SHELLAll Shell:cat/etc/shells under the current systemView CentOS System hostname Format: Echo $PS 1Distinguish internal or external commands: Type CDWhich find the locatio

I. att format Linux Assembly syntax format In att Assembly format, Register names must be prefixed with '%'. In Intel assembly format, Register names do not need to be prefixed. For example: Att format Intel format Pushl % eax Push eax In att Assembly format, the prefix '$' is used to represent an immediate operand. In Intel assembly format, the representation of immediate numbers does not contain any prefix. For exa

. As we all know,linux system everything is a file, so each process has its file descriptor, The Nginx process writes its own file descriptor to the Nginx.pid, and we need to tell Nginx to reopen a new log file (the configuration details of the log file can be seen here, simply by letting the log record what. So we need this directive:kill -USR1 `cat ${pid_path}`This instruction means: first cat to Nginx PID, is an integer, and then send the signal

Downloadwget http://.....tar.gzExtractTAR-ZXVF xxx.tar.gzcd XXX./configure--prefix=/usr/local/xxx--with-x=/usr/local/xCompileMakeInstallationMake installNginx Start/usr/local/nginx/sbin/nginx Stop/usr/local/nginx/sbin/nginx-s Stop Focus/usr/local/nginx/sbin/nginx-s Reload httpd start, shut down, restart/usr/local/http/bin/apachectl-k [Start | stop ...]Find processPs-ef|grep xxx The above describes the Linux installation software memorandum, i

that TR points to the new TSS, and the task switching is completed. The CPU can also implement task switching through the JMP and CALL commands. when the jump or CALL target segment actually points to a TSS description in the GDT table, a task switching will occur. 2. Linux task switching and field protection ?? Intel is well-designed for task switching and provides a simple task switching mechanism. Howev

Becoming a Senior Programmer proficient in Linux programming has always been the goal of many friends. According to statistics from chinacache, the monthly salary of Linux programmers in Beijing is 1.8 times that of Windows programmers, 2.6 times that of Java programmers, and 2.9 times that of Windows programmers. At the same time, the data shows that with the increase of work experience, the income gap bet

. System call access is a very frequently used process that can be used thousands of times per second, and its time efficiency is important. Moreover, the system call access process also involves the user space and system space between the switch, and for this purpose some instructions in the C language does not have the corresponding language components, so, the system calls to enter and return obviously must use assembly language to write.In some special occasions, the space efficiency of a pr

entry and return of system calls is a typical example. System call access is a very frequently used process that can be used thousands of times per second, and its time efficiency is important. Moreover, the system call access process also involves the user space and system space between the switch, and for this purpose some instructions in the C language does not have the corresponding language components, so, the system calls to enter and return obviously must use assembly language to write.

3.4 manage I/O port resources We all know that the x86 processor using I/O ing implements a separate address space for the peripherals, that is, the "I/O space" (I/OOr "I/O port space". Its size is 64 KB (0x0000-0xffff ). Linux implements the concept of "I/O port space" on all platforms it supports. Because I/O space is very small, even if the peripheral bus has a separate I/O port space, not all peripherals place their I/O Ports (registers) maps to "

This document copies the content of the following two documents: (1) "handling Linux kernel missing page exceptions using abnormal tables" http://www-128.ibm.com/#works/cn/linux/kernel/l-page/index.html; (2) "implementation and understanding of user/kernel space data replication" www.linuxforum.net. The address ing of user processes is sometimes not established (such as a stack), and the page in pg_dir has