연산자 우선순위 및 결합순서
 컴퓨터언어는 개발자를 비롯한 컴퓨터 과학/공학자들의 요구에 따라 다양하게 진화되었다. 최대한 인간의 일반적인 사고를 바탕에 두고 문법과 체계를 만든 것이지만, 아무래도 언어 개발자들의 마인드가 포함되어 있어 일반에게는 약간 어렵기도 한 것 같다. 다음은 C++ 연산자 우선순위표이다. 이것을 잘 알아야, 복잡한 포인터와 구조체, 배열이 섞인 복잡해 보이는 식도 기계적으로 풀어낼 수 있다. 그러므로 다음은 반드시 암기 가능하면 이해할 사항이다.

간략본(http://www.winapi.co.kr/clec/cpp1/5-4-1.htm)

자바(http://www.tech-faq.com/lang/ko/java-operator-precedence.shtml)
자바 연산자 우선순위는 자바를 결정하는 방법을 평가 연산자를 사용하여 첫 번째합니다.

In this chart, operator precedence is displayed from highest precedence to lowest precedence. 이 차트, 연산자를 우선 순위가 높은 우선 순위가 낮은 우선순위를 표시합니다.

Notes: 참고 사항 :

• Expressions inside parentheses are evaluated first 괄호 안에 표현을 평가할 수있습니다 첫 번째
• Nested parentheses are evaluated from the innermost parentheses to the outermost parenthesis. 중첩된 괄호는 괄호를 안쪽에서 바깥쪽 괄호을 평가합니다.
• Operators in the same row in the chart have equal precedence. 차트에서와 같은 행에 연산자를 우선 순위가 동일합니다.

참고
- 이쪽 블로그를 보면 연산자 우선 순위에 대한 여러 생각들을 정리해 놓았다

출 처 : http://learder.tistory.com/827019

The code is maintained by a guy named buserror. I'll provide his information at the end of this howto.

At the time of writing this, I had some issues with getting Buserror's U-Boot working correctly.

The code that is in his git repository, doesn't run from RAM without a modification to the source. So here are the instructions that I gathered for altering and compiling it, and getting it going on the Mini2440 and Micro2440 board.

For this to work, I'm going to assume that you have a crosscompiler set up. Later on, I will probably write an entry here about setting that up, but not now. I'm also assuming you have git installed.

Step 1: Get the source

mkdir uboot ; cd uboot

git clone git://repo.or.cz/u-boot-openmoko/mini2440.git

Step 2: Set your cross compiler prefix so you don't end up compiling this for x86.

export CROSS_COMPILE=arm-none-linux-gnueabi-

Step 3: Modify the source to disable CONFIG_USE_IRQ. Open include/configs/mini2440.h.

#define USE_920T_MMU

//#define CONFIG_USE_IRQ                    1       /* Needed for USB device! */

Disabling this obviously disables the use of USB During boot. You can fix this by reflashing a normal copy of u-boot from within u-boot once this is up and running. In the above example, I commented it out but you can probably just change the 1 to a 0.

Step 4: Make and compile.

 cd ../../

 make mini2440_config

 make

Assuming this all compiles correctly, you will have a u-boot.bin file in your directory now as well as a 2k and 16k block size bin file. Those two are for flashing inside of U-Boot. The normal .bin is for flashing from ram from within supervivi.

Step 5: Flashing u-boot to the mini2440. In this example, we'll be using DMW for Windows to transfer the binary over to the board with the supplied USB cable.

5a. Set boot switch to NOR.

5b. When supervivi pops up, hit q for supervivi shell.

5c. Load the image in to ram at 0x32000000 (6 zeros) memory location.

 shell> load ram 0x32000000 <uboot bin size in bytes> u-boot

5d. Use DNW to transfer the u-boot.bin from your computer to the board.

5e. Execute the loaded bin file you loaded in to RAM.

shell> go 0x32000000

5f. You should now be inside u-boot at a MINI24440# prompt. Now we prepare the NAND.

MINI2440# nand scrub

5g. Create the bad block table.

MINI2440# nand createbbt

5h. Write the u-boot that we're running at 0x32000000, to the NAND.

MINI2440# nand write.e 0x32000000 0x0 <u-boot bin size in hex>

5i. Partition the NAND.

MINI2440# dynpart

5j Create the dynamic environment space for u-boot.

MINI2440# dynenv set u-boot_env

5k. Save the environment to NAND.

MINI2440# saveenv

You can now set the boot switch back to NAND and reboot the system. It should pop up with U-Boot and give you a MINI2440# uboot prompt. From this point on you can do all your work inside U-boot for loading images for the kernel and for the filesystem. I would like to note though, that in the above examples, you need to know your u-boot bin file size in both bytes and in hex. You can use google to convert the file size in bytes to hex. (i.e. "233907 to hex" in the google search box). I recommend trying to run u-boot without the source modification first before disabling IRQ because I'm guessing at some point, buserror or someone else will figure out why it won't run from RAM with that enabled. If it fails, and you can always modify the source and recompile.

I'd like to note that I collected these instructions from various sites and I've re-worded and explained them some to help. I hope that this helps you.

Here are some useful links for u-boot and other things:

http://bliterness.blogspot.com/ - Busseror's blog

http://code.google.com/p/mini2440/ ... - Buserror's Google code page.

http://repo.or.cz/w/openembedded/mi... - Git repository for the modified Openembedded

http://repo.or.cz/w/u-boot-openmoko... - Git repository for u-boot

UPDATE: MAY 8th, 2010: As of writing this update, the code in the git repository already has the above modification to the code. If you for any reason require USB support on your bootloader, you will need to uncomment the line that is commented out above and recompile.

UPDATE MAY 31st, 2010: There have been some problems with the current repository code and it won't run from RAM for some devices. So here's a quick workaround.

• 1. Switch the system to NOR and boot with supervivi.
• 2. hit v in supervivi
• 3. i uploaded the u-boot.bin file
• 4. switch the system to NAND and boot up with u-boot. You'll get some errors.
• 5. Run nand scrubs and createbbt
• 6. switch back to NOR
• 7. hit v again and upload U-boot since you just erased it.
• 8. switch back to nand and it should boot up with minimal errors using u-boot.
• 9. run the dynpart and dynenv and saveenv as mentioned above.
• 
  

You should have a working u-boot... I'm currently getting an error about it not seeing my nand but it seems to be able to access it. Maybe you guys can let me know if you see anything wrong. I am suspecting there is a problem with the new u-boot code. Maybe buserror can shed some light on this.

• 1 About
• 2 Preparations
  • 2.1 Toolchain
• 3 Setting up the bootloader
  • 3.1 Compiling uboot
  • 3.2 Flashing uboot
  • 3.3 Configure uboot
• 4 Kernel
  • 4.1 Compilation
  • 4.2 Kernel Modules
  • 4.3 Flash kernel
  • 4.4 Configure uboot
• 5 Setting up embedian
• 6 Bit Baking Angstrom, and QT Embedded 4
  • 6.1 Getting the required software
  • 6.2 Adding QT to baking recipes
  • 6.3 running the bitbake
• 7 Troubleshooting
  • 7.1 Write errors
  • 7.2 Python Alignment trap, Segmentation fault
  • 7.3 Messed Up Screen Positions( or TS calibration) IN QT
• 8 Links

About

This is a howto install uboot and a new kernel on the mini2440. Big thanks to BusError for the instructions and guidance. DISCLAIMER: This worked for me, if it eats your cat or burns your kitchen sink, don't blame me.

Preparations

Toolchain

I used this one: http://www.codesourcery.com/sgpp/lite/arm/portal/package3696/public/arm-none-linux-gnueabi/arm-2008q3-72-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2

Add the bin dir to the $PATH. If you have a toolchain with another prefix (like arm-linux-) adapt the CROSS_COMPILE environment variable in the next steps.

Setting up the bootloader

Compiling uboot

Clone the git tree:

mkdir uboot ; cd uboot

git clone git://repo.or.cz/u-boot-openmoko/mini2440.git

Setup cross compiling:

export CROSS_COMPILE=arm-none-linux-gnueabi-

or edit your .bashrc eg.

export CROSS_COMPILE=arm-none-linux-gnueabi-

export PS1="\[\033[1;34m\]\u \[\033[0m\]\w:\$: \[\033[0m\]"

#export PS1="\u:\w\$>"

LS_OPTIONS="--color=auto"

alias ls="ls $LS_OPTIONS"

Prepare the mini2440 target:

cd mini2440

make mini2440_config

Compile:

make all

This will give you a "u-boot.bin". If you get an error about a missing whatever-gcc, verifiy if there is a hardcoded CROSS_COMPILE setting in the Makefile

Flashing uboot

We use the installed vivi bootloader to load uboot via usb. Power the board off, set the NOR switch to on, power the board on. You'll get the vivi output on the serial console. Press 'q' to go to the shell and do the "load flash" on address 0 with the size of "u-boot.bin" (238232 bytes in this example):

[q] Goto shell of vivi                                                          

Enter your selection: q                                                         

Supervivi> load flash 0 238232 u                                                

USB host is connected. Waiting a download.                                      

Use the "s3c2410_boot_usb" utility (http://mini2440.googlecode.com/files/s3c2410_boot_usb-20060807.tar.bz2) to upload the "u-boot.bin" via usb:

./s3c2410_boot_usb u-boot.bin 

You'll see something like this as output, ignore the error message:

csum = 0x9a6e

send_file: addr = 0x33f80000, len = 0x0003a298

Error downloading program

and this on the serial console:

Now, Downloading [ADDRESS:30000000h,TOTAL:238242]                               

RECEIVED FILE SIZE:  238242 (232KB/S, 1S)                                       

Downloaded file at 0x30000000, size = 238232 bytes                              

Found block size = 0x0003c000                                                   

Erasing...    ... done                                                          

Writing...    ... done                                                          

Written 238232 bytes                                                            

Supervivi>

Then you see

MINI2440 # saveenv


Saving Environment to NAND...


Erasing Nand...nand_erase: attempt to erase a bad block at page 0x00000260

Try

MINI2440 # nand scrub

...

Really scrub this NAND flash? <y/N>

press y and enter. After erasing make

MINI2440 # nand createbbt

press y and enter. Now you can save the environment

 MINI2440 # saveenv

Now power off the board, set the NOR switch back to off, and power on the board. We verify the version and then prepare config storage in flash:

MINI2440 # version                                                              

                                                                                

U-Boot 1.3.2-dirty-moko12 (Mar  8 2009 - 13:50:19)  


MINI2440 # dynenv set 40000                                                     

device 0 offset 0x40000, size 0x3fc0000                                         

45 4e 56 30 - 00 00 04 00           


MINI2440 # saveenv                                                              

Saving Environment to NAND...                                                   

Erasing Nand...Writing to Nand... done                                          


MINI2440 # reset                                                                

Configure uboot

do a "printenv" to show active settings. Adjust the IP for uboot and the tftp server. We need proper IP connectivity to load the kernel with tftp. "setenv" is your friend. "saveenv" stores the setting to flash.

Kernel

Compilation

Fetch from git:

mkdir kernel ; cd kernel

git clone git://repo.or.cz/linux-2.6/mini2440.git

cd mini2440

mkdir -p ../kernel-bin

Generate .config from mini2440 template:

CROSS_COMPILE=arm-none-linux-gnueabi- ARCH=arm make O=../kernel-bin/ mini2440_defconfig

(optional) if you want to modify kernel modules use this command afterwards:

(optional if you don't have libncurses5-dev) apt-get install libncurses5-dev

cd ../kernel-bin

make ARCH=arm menuconfig

cd ../mini2440

Compile kernel and modules:

CROSS_COMPILE=arm-none-linux-gnueabi- ARCH=arm make O=../kernel-bin/

Generate "uImage" with the "mkimage" tool:

../uboot/mini2440/tools/mkimage -A arm -O linux -T kernel -C none -a 0x30008000 -e 0x30008000 -d ../kernel-bin/arch/arm/boot/zImage /tftpboot/uImage

Kernel Modules

To create the dynamically loaded kernel modules, which would go into the root file system later on do this:

CROSS_COMPILE=arm-none-linux-gnueabi- ARCH=arm make O=../kernel-bin/ modules

CROSS_COMPILE=arm-none-linux-gnueabi- ARCH=arm make O=../kernel-bin/ INSTALL_MOD_PATH=.. modules_install

After this step, there should be a directory ../lib which would contain the dynamically loaded modules(drivers). This folder would go to the root file system of your board, for example I have my filesystem on a sd card. I would stick the SD card in the PC, and mount it and then copy the modules as:

 cp ../lib/modules/2.6.32-rc8/ /media/rootfs/lib/modules/ -r

don't forget to

sync

umount /media/*

Flash kernel

Verify partitions, we need the offset for the kernel partition (probably 0x60000):

mtdparts

Erase the kernel partition:

nand erase 60000 <padded size>

Load the kernel with uboot into ram:

tftp 0x32000000 uImage

Note the size, pad it to 512 byte and use the nand write command to flash it:

nand write 32000000 60000 <padded size>.

Configure uboot

We use a nfs chroot for now:

setenv bootargs console=ttySAC0,115200 noinitrd init=/sbin/init mini2440=1tb ip=192.168.80.12 root=/dev/nfs rw nfsroot=192.168.80.1:/home/public/arm

This is helpful for automatic booting:

setenv bootcmd 'nboot.e kernel ; bootm'

Setting up embedian

Follow this nice howto from BusError http://code.google.com/p/mini2440/wiki/Emdebian

Bit Baking Angstrom, and QT Embedded 4

If you are using Fedora follow this link : http://www.electronics.diycinema.co.uk/embedded/mini2440/bitbaking-the-kernel-angstrom-and-qt4-embedded-all-at-once/comment-page-2/#comment-498 , otherwise follow here:

Getting the required software

cd ~

mkdir OE

cd OE

git clone git://repo.or.cz/openembedded/mini2440.git openembedded

Getting other required Softwares

sudo apt-get install gawk diffstat help2man texi2html texinfo build-essential subversion cvs unzip texinfo git-core

sudo dpkg-reconfigure dash

and choose "<No>" from the menu.

Then we create a helper for ourselves:

gedit ~/OE/source-me.txt

and past the following, and change the /home/ashkax to your own home directory address.

export OETREE="/home/ashkax/OE"

BBPATH=${OETREE}/:${OETREE}/openembedded/

echo Setting up dev env for Ångström

if [ -z ${ORG_PATH} ] ; then

ORG_PATH=${PATH}

export ORG_PATH

fi


if [ -z ${ORG_LD_LIBRARY_PATH} ] ; then

ORG_LD_LIBRARY_PATH=${LD_LIBRARY_PATH}

export ORG_LD_LIBRARY_PATH

fi


PATH=${OETREE}/openembedded/bitbake/bin:${ORG_PATH}

LD_LIBRARY_PATH=

export PATH LD_LIBRARY_PATH BBPATH

export LANG=C

export BB_ENV_EXTRAWHITE="MACHINE DISTRO OETREE ANGSTROM_MODE ANGSTROMLIBC LIBC"

sudo sysctl vm.mmap_min_addr=0

echo "Altered environment for OE Development"

This file that we just created will be used later on, to setup the compiler... Now lets edit the bitbake configuration file to tell bit bake we like it to compile the QT embedded for us too:

cd ~/OE/openembedded

wget http://www.electronics.diycinema.co.uk/wp-content/uploads/2009/11/local.conf.txt

gedit local.conf.txt

 

now change all the doug to your own user name, save the file and quit gedit. Then

cp local.conf.txt conf/local.conf

Alternatively you can use the original sample file and edit it to your liking:

cd openembedded

gedit mini2440_local_conf_example.conf

cp mini2440_local_conf_example.conf conf/local.conf

Adding QT to baking recipes

gedit ~/OE/openembedded/recipes/images/mini2440-image.bb

it would be something like:

#Angstrom bootstrap image

IMAGE_PREPROCESS_COMMAND = "create_etc_timestamp"

ANGSTROM_EXTRA_INSTALL ?= ""


DEPENDS =  "task-base-extended \

psplash-zap \

esekeyd u-boot-utils tslib \

i2c-tools i2c screen rsync nfs-utils \

directfb gdbserver directfb mtd-utils \

"


IMAGE_INSTALL = "task-base-extended \

${ANGSTROM_EXTRA_INSTALL} \

psplash-zap qt4-embedded\

esekeyd u-boot-utils tslib-calibrate tslib-tests \

i2c-tools i2c screen rsync nfs-utils-client \

directfb gdbserver directfb mtd-utils \

rsvg pango \

"


export IMAGE_BASENAME = "mini2440-image"

IMAGE_LINGUAS = ""

inherit image

running the bitbake

Now all you have to do is source the script from wherever you put it:

source ~/OE/source-me.txt

cd ~/OE/openembedded/

bitbake mini2440-image

If you get an error trying to build a package try cleaning it: bitbake -c clean INSERTPACKAGENAME

Then try and build the image again. Maybe you won’t have this problem. I guess it’s either because the checksum parser failed to build or my hdd is dodgy. It only happened once on binutils but worked fine after cleaning it.

A few hours later if all goes well you should have images in: ~/OE/oetmp/deploy/glibc/images/mini2440/

Obviously that directory depends on what you setup in the local.conf.

but, for a fun start boot up your mini2440 with the new image that you've just created and issue the following command:

ts_calibrate 

ts_test

qtdemo -qws

Troubleshooting

Write errors

When you have bad blocks in NAND, you'll get write errors. This gives more information: http://wiki.openmoko.org/wiki/NAND_bad_blocks

Clear the flash (do not reset the board till uboot is reinstalled, or you need to use NOR/vivi to reinstall uboot via usb):

nand scrub

Create new bad blocks table:

nand createbbt

Reflash uboot (use the size in the output from the tftp command and pad it to hit 512 byte boundaries for the nand write command)

tftp 0x32000000 u-boot.bin

nand write 32000000 0 <size of u-boot.bin>

reset

Create dynamic partitions:

dynpart

dynenv set u-boot_env

saveenv

reset

And then use write.e to write to the mtdparts, e.g.:

tftp 0x32000000 uImage

nand write.e 32000000 kernel

nboot.e kernel

Python Alignment trap, Segmentation fault

This error and some other errors related to illegal instructions happened because all packages are compiled with -mthumb though the kernel and modules use -mno-thumb. The mix of instruction sets seem to cause problems. A hotfix is to edit your conf/distro/include/angstrom.inc and change the line: ANGSTROM_ARM_INSTRUCTION_SET_armv4t = "thumb" to ANGSTROM_ARM_INSTRUCTION_SET_armv4t = "arm"

The default for the mini2440 is -mno-thumb but for some reason (save memory space, maybe?) the angstrom distro overrides this for all armv4t family processors.

Messed Up Screen Positions( or TS calibration) IN QT

If the resolution is messed up or you can run the ts_calibrate but the hitting points are out of range, it may be because of the boot arguments.. Reboot your system, press a key in startup to go to uboot environment and make sure mini2440=0tb for 3.5" screen, and mini2440=1tb for 7" screen. Try using the commands printenv, and setenv to do so.

Try ts_calibrated after booting.

Links

http://bliterness.blogspot.com/

http://code.google.com/p/mini2440/

http://blog.cor-net.org/ (Qt 4.5 on mini2440)

http://wiki.openembedded.net/index.php/Getting_Started

http://www.sereno-online.com/site/2010/05/01/qt-4-6-2-installation-procedure-for-friendlyarm-mini-2440-board/ (Qt 4.6.2 on mini 2440)

출 처 : http://wiki.linuxmce.org/index.php/Mini2440#Setting_up_embedian

안녕하세요?

현재 국내에 GIT에 대한 제대로 된 문서가 없기에,  GIT 사용자 가이드에 대하여 번역을 시작하게 되었습니다.

번역의 오류로 틀린 내용이 있을 수도 있으니, 오류 발견시 댓글을 남겨주시면 감사하겠습니다.

GIT 사용법 (ProGIT) - 1.4. GIT 설치

원본 : ProGIT  Book(http://progit.org)

번역 : 김재훈(이솝 임베디드 포럼, http://www.aesop.or.kr)

1.4. GIT 설치

이제 GIT를 사용하는 방법에 대해 알아보도록 합니다. 우선, GIT를 사용하기 위해서는 GIT를 설치해야 합니다.

GIT를 설치하는 방법에는 소스를 받아서 컴파일 하는 방법과 플랫폼에 따라 각각 존재하는 패키지를 사용하여 설치하는  두 가지 방법이 있습니다.

1.4.1. GIT 소스 컴파일 방법

GIT 소스를 받아 직접 컴파일하여 설치하는 방법은 가장 최신의 GIT 버전을 적용할 수 있다는 것이 장점 입니다.

GIT는 버전이 올라갈 때마다, 유저 인터페이스 및 기타 기능들이 향상 되고 있습니다.

따 라서, 많은 Linux 배포본들이 매우 오래된 GIT 버전을 패키지로 제공하는 일이 자주 있기 때문에, 만약 사용자가 소스를 컴파일하는 방식에 위화감을 느끼지 않는다면 GIT 소스를 받아 직접 컴파일 하는 방법이 최신 버전을 사용하는 가장 좋은 방법 입니다.

우선 GIT 소스를 컴파일 하기 위해서는 GIT 컴파일에 의존적인 라이브러리들을 우선 설치할 필요가 있습니다.

GIT 컴파일에 의존적인 라이브러리는 curl, zlib, openssl, expat, liviconv 입니다.

만 약 사용자가, Fedora 배포본 기반의 리눅스 시스템을 사용하고 있다면 yum 명령을 사용하고, uBuntu Linux와 같은 Debian 계열의 운영체제는 apt-get 명령을 이용하여 의존적인 라이브러리를 손쉽게 설치 할 수 있습니다.

$ yum install curl-devel expat-devel gettext-devel \
  openssl-devel zlib-devel

$ apt-get install curl-devel expat-devel gettext-devel \
  openssl-devel zlib-devel

GIT를 컴파일하는데 필요한 의존적인 라이브러리를 모두 설치하였다면,  이제 GIT의 웹 사이트에서 최신판의 Snapshot을 다음 명령을 통해 가져올 수 있습니다.

http://git-scm.com/download

이제, 다음 명령으로 소스를 컴파일 하고 인스톨 합니다.

$ tar -zxf git-1.6.0.5.tar.gz
$ cd git-1.6.0.5
$ make prefix=/usr/local all
$ sudo make prefix=/usr/local install

GIT가 잘 컴파일 되었다면, 이제 GIT 명령을 이용하여 다음과 같이 최신판의 GIT 소스를 GIT를 이용하여 얻어올 수 있습니다.

$ git clone git://git.kernel.org/pub/scm/git/git.git

1.4.2. Linux 배포본에서의 설치

리눅스 배포판에서 제공하는 패키지 설치 프로그램을 통해 설치를 하고 싶은 경우, 다음과 같은 명령을 사용하여 설치를 진행 할 수 있습니다.

Fedora 및 Redhat 계열 배포본의 경우 다음의 명령을 사용 합니다.

$ yum install git-core

Ubuntu와 같은 Debian 계열 배포본의 경우 다음의 명령을 사용 합니다.

$ apt-get install git-core

1.4.3. Macintosh 에서의 설치

MacOS에 GIT를 설치하는 방법은 두 가지 방법이 있습니다.

이중에서 가장 간단한 방법은 GUI 방식의 Gitinstaller를 사용하는 방법 입니다.

이 Gitinstaller는 Google Code 페이지의 다음의 사이트에서 다운로드 할 수 있습니다.

http://code.google.com/p/git-osx-installer

이외에 또 한 가지의 방법은 MacPorts(http://www.macports.org)에서 GIT의 설치본을 받아오는 방법 입니다.

여러분의 Macintosh 컴퓨터에 Macports를 설치한 상태라면, Git를 다음과 같은 명령으로 설치할 수 있습니다.

$ sudo port install git-core +svn +doc +bash_completion +gitweb

1.4.4. Windows 에서의 설치

Windows 운영체제에 GIT를 설치하는 방법은 매우 간단합니다.

msysGit 프로젝트는 Windows에서 간단하게 GIT를 인스톨할 수 있는 방법을 제공하고 있습니다.

따라서, Google의 Code 페이지로부터, Installer를 받아와 실행만 하시면 됩니다.

http://code.google.com/p/msysgit

설치가 끝나면, Linux 처럼 커맨드 라인 방식 및 Windows의 일반적인 GUI 방식 양쪽 모두를 사용할 수 있습니다.

출 처 : http://ippuu.tistory.com/125