原创 c volatile keyword and memory cache

The 'volatile' keyword is used to tells the compiler to fetch a variable each time from memory rather then use a "compi

2020-03-08 16:28:44

原创 fork() printf()

#include <stdio.h> #include <sys/types.h> #include <unistd.h> int main(void) { int i; for(i=0; i<2; i++){

2020-03-07 09:15:42

原创 find variale value in ELF file

copied from stackoverflow. First, you would use readelf to determine the virtual address of the variable (where it live

2020-03-06 00:50:13

原创 add a new system call for x86

  #define T_SYSCALL 64 // system call #define SYS_fork 1 #define SYS_sleep 2 #define SYSCALL(name) \

2020-03-03 09:01:51

原创 vscode regex replace

question: replace following line in left to its right part. [SYS_write]   sys_write,    -> [SYS_write]   "write", solut

2020-03-03 09:01:51

原创 network byte order

copied from wiki. Many IETF RFCs use the term network order, meaning the order of transmission for bits and bytes over

2020-02-28 16:26:36

原创 C function implementation: memcpy and strcpy and others

1. memcpy. An often being asked interview question. The key is to handle address overlap. void *memcpy(void *dest, con

2020-02-28 16:26:36

原创 cut with tr

question: delete docker images with none tag. sample output: hfyin@hfyin-VirtualBox:~/projects$ docker image ls | grep

2020-02-27 14:27:44

原创 git command

1. check a commit before a specified commit Use git show HEAD^1. You can replace HEAD with your commit-hash refer: http

2020-02-27 14:27:44

原创 register sram dram nor flash nand flash

refer: https://zhuanlan.zhihu.com/p/70273183 https://www.zhihu.com/question/20075426 上面的兩個文章總結的挺好的，補償一點： 1. sram, dram都

2020-02-25 01:08:27

原创 c data type size

copied from wiki: The actual size of the integer types varies by implementation. The standard requires only size relati

2020-02-25 01:08:27

原创 c list sample code

c list sample code. The list interface may varies depends on use case. It seems the last one is more popular. However,

2020-02-22 00:06:47

原创 c variable-length argument lists

a simple program demostrate c variable-length argument lists, and how to refer variable-length argument in c macro. #i

2020-02-22 00:06:13

原创 give IAM user billing permission

1. config policy，attach policy to IAM user or group. 2. root user login, and go to account page, then find 'IAM User an

2020-02-22 00:06:13

原创 stabs: c語言如何使用stabs存放debug信息，以及如何使用stabs查找函數, stacktrace 如何實現

stabs 已經被 DWARF 替代...... stabs是什麼 Stabs (Symbol Table String) refers to a format for information that describes a progr

2020-02-22 00:06:13