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Embedded System

親手打造 HD 播放器

錢逢祥錢逢祥Fred Chien

[email protected]

本課程目標ARM 的初步認識

快速入門 Embedded System

理解 Linux 架構細節

親手打造實際應用

作中學

Embedded System?完全嵌入受控器件內部，為特定應用而設計的專用電腦系統

Embedded System Example

為何使用 ARM ?Advanced RISC Machine

ARM Advantage

高性能

低耗電

體積小

總生產成本低

Marketing

手機

PDA/MID/ 消費性電子產品

微型裝置

家電產品

各種網路設備（ Router, Wifi AP... ）

工業控制領域

ARMARM 晶片的眾多製造商晶片的眾多製造商

TI

Atmel

Broadcom

Freescale

Samsung

Marvell

IBM

Intel

Sharp

任天堂

Nvidia

… more

ARM HistoryAcorn Computers Ltd 自 1983 年開始研發

目標是打造類似 MOS Technology 6502 的晶片

直至 1985 年打造出第一顆 ARM1 晶片

1980 年代晚期 Apple 與 Acorn 合作研發新晶片

1990 年時設計團隊組成 Advanced RISC Machines Ltd.

這次選用的開發板

DevKit 8000(Beagleboard Clone)

DevKit 8000 接頭圖解

Processor

TI 德州儀器 OMAP3530600-MHz ARM Cortex™-A8

430-MHz TMS320C64x+™DSP Core

Core Supply is 0.8V to 1.35V

Video/Audio Support

S-Video

HDMI (1280x720 DVI-D)

LCD (2048x2048 24bits)

Mic In

Audio Out

Our LCD and Touch Panel

4.3 inch

480x272 24bits

Transfer Interface

USB2.0 Host/OTG (480Mbps)

SD/MMC

10/100M Ethernet

RS232

More DevKit8000 Specifications

110mm x 95mm

Input Vol +5V

0.5A 5V 2.5W

ARM Development

Serial Port (COM Port, USB)

Booting from NAND/SD/NFS

UART, SDIO, SPI, GPIO

General Booting Progress

BIOS (x86 Only)

Boot Loader

Linux Kernel

/sbin/init

RC Scripts (Services)

Graphical User Interface

Applications

Standby

Details for PC

Load BIOS

BIOS checks Hardware and scan Harddrive (POST)

Find MBR from Harddrive

Jump to MBR(Boot Loader)

Boot Loader Loads Linux kernel

Jump to Linux Kernel

Detect and Initiate Hardware

Mount Rootfs from Harddisk, Ramdisk, other storages...etc

Execute /sbin/init or /init

init program reads /etc/inittab

init program executes scripts to start up services(Initializing system, daemon, servers...etc)

GDM/SLIM service and Graphical Environment(Xorg server) are started

After login, starting GNOME/KDE/Other desktop environment (Here is Chromium Browser for Chromium OS)

Bootstrap

Details for ARM

xloader (Initializing Clock and RAM)

Jump to RAM to start up "uboot"

uboot Loads Linux kernel from NAND/NFS/SD Card

Jump to Linux Kernel

Detect and Initiate Hardware

Mount Rootfs from Harddisk, Ramdisk, other storages...etc

Execute /sbin/init or /init

init program reads /etc/inittab

init program executes scripts to start up services(Initializing system, daemon, servers...etc)

GDM/SLIM service and Graphical Environment(Xorg server) are started

After login, starting GNOME/KDE/Other desktop environment (Here is Chromium Browser for Chromium OS)

Bootstrap

Bootstrap for PC

POST(Power On Self Test) Initializes system hardware and chipset registers

Initializes power management

Tests RAM (Random Access Memory)

Enables the keyboard

Tests serial and parallel ports

Initializes hard disk drive controllers

Displays system summary information

Compares the system configuration data

Looks for the boot program

Bootstrap for ARMxloader

Initializes Clock

Initializes RAM

Starting up uboot

ubootLoad Kernel(From NAND/SD/Ethernet)

Execute kernel

Words for ARM Development

BSP

DSP

OpenGL|ES

Development Environments

OpenEmbedded

Emdebian

Ubuntu for ARMDebian Based

Linux 基礎

Root Filesystem/bin – executable binary for basic commands (ls, mount...)

/dev – device files (tty*, ram*, null, loop*, sd*...)

/etc – config files (resolv.conf, ldocnfig, hostname...)

/lib - libraries

/home – user's data

/sbin – executable binary for utility (mke2fs, init, ifconfig...)

/tmp

/usr/bin - executable binary for software

/usr/lib – libraries for software

/usr/sbin - executable binary for software

/proc – Linux kernel informations

/sys – Linux kernel informations

Linux Booting Progress

Linux Kernel

/sbin/init or /init

/etc/init.d/rcS

/etc/init.d/rc

/etc/init.d/rc*.d/S* (services)

X

GDM

GNOME/KDE/LXDM Desktop Environment

Graphical Applications

GUI

Early Stage

Understanding LiveCD/USB

xPUD

Damn Small Linux

Knoppix

More...

Analyse xPUD

Made in Taiwan

Size: 25MB

Boot Time: ~6s

Based on Ubuntu/Debian/Fedora...etc

xPUD Booting Progress

Bootloader Load Kernel/initrd

Jump to Kernel

Uncompress initrd

Mount initrd

Execute /init

Initializing system

Execute startx

Execute /etc/X11/xinitrc

運用工具了解 Linux 細節

dpkg -i <package>● 安裝 Package

dpkg -S <path>● 找出目標檔案所屬的 Package

dpkg -L <package>● 列出 Package 內包含的檔案清單

重要的檔案和程式

/etc/resolv.conf

/etc/passwd and /etc/groups

/etc/ldconfig

/sbin/ifconfig

/sbin/iwconfig

/sbin/insmod and /sbin/modprobe

一步步製作自己的 OS

Kernel

Command

Utility

Library

Write Scripts (/init)

Rootfs

親手使 ARM 開機

Power ON

xLoader

Uboot

Linux Kernel

Mount Rootfs

ARM 的開機流程

Prepare

Kernel (uImage) Root Filesystem

Uboot Commands

printenv - 列出環境設定

setenv - 設定變數

saveenv – 將環境設定燒回 Flash 供下次使用

boot - 開始執行開機動作

Booting from MMC/SD Card

mmcinit

fatload mmc 0:1 0x82000000 uImage

bootm 0x82000000

FAT File SystemuImage(Linux kernel)

EXT2 File System/bin /lib /sbin /usr ...

0:1

MMC/SD CardMMC/SD Card

Booting from Ethernet

Devkit8000

PC

uImage via tFTPuImage via tFTP

Rootfs via NFSRootfs via NFS

tFTP ServerNFS Server

IP: 140.128.36.30

IP: 140.128.36.210

ServerServer

Inatall tftp server

Install Package

sudo apt-get install tftpd openbsd-inetd

Create a Directory

mkdir /home/student/tftp

Setting /etc/inetd.conftftp dgram udp wait nobody /usr/sbin/tcpd /usr/sbin/in.tftpd /home/student/tftp

Restart tftp serversudo /etc/init.d/openbsd-inetd restart

Install NFS Server

Install Package:

sudo apt-get install nfs-kernel-server

Create a Directory:

mkdir /home/student/roofs

Add a line to /etc/exports:

/home/student/roofs *(rw,no_root_squash,no_subtree_check,async)

Restart NFS server:

sudo /etc/init.d/nfs-kernel-server restart

Uboot Settings for tFTP

setenv bootcmd tftpboot 82000000\; bootm 82000000;

setenv ipaddr 140.128.36.30

setenv serverip 140.128.36.210

setenv bootfile uImage

setenv bootargs console=ttyS2,115200n8 noinitrd root=/dev/nfs rw nfsroot=140.128.36.210:/home/student/rootfs ip=140.128.36.30::140.128.36.254:255.255.255.0:non:eth0:off omapdss.def_disp=lcd

boot 同一行

實例安裝 Android

Suppose We have...

A Linux Kernel (uImage)

An Android Rootfs (android-rootfs.tgz)

Setup Android on Server

Move Kernel Image to tftp Directory:

mv uImage /home/student/tftp

Setup Android Rootfs on NFS Directory:

sudo tar -zxvf android-rootfs.tgz -C /home/student/rootfs

Setup Uboot

Setting bootargs for kernel:

setenv bootargs console=ttyS2,115200n8 noinitrd root=/dev/nfs rw nfsroot=140.128.36.210:/home/student/rootfs ip=140.128.36.30::140.128.36.254:255.255.255.0:non:eth0:off init=/init omapdss.def_disp=lcd

同一行

自己做Kernel + Rootfs

How to install Cross-compiler

Add Repository to /etc/apt/source.list● deb http://www.emdebian.org/debian/ unstable main

Install Emdebian Tools

● apt-get install emdebian-tools

Install cross-compiler and libraries

● apt-get install linux-libc-dev-armel-cross● apt-get install libc6-armel-cross libc6-dev-armel-cross● apt-get install binutils-arm-linux-gnueabi● apt-get install gcc-4.3-arm-linux-gnueabi● apt-get install g++-4.3-arm-linux-gnueabi

How to Cross-Compile kernel

Get Kernel Source

Prepare Kernel Config

Edit .config (make menuconfig)

Cross-compile for ARM

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- uImage

Build up Root Filesystem

sudo apt-get install rootstock dctrl-tools

bzr branch lp:project-rootstock

cd projector

sudo ./rootstock –fqdn beagleboard –login ubuntu –password temppwd –imagesize 2G –dist karmic –serial ttyS2 –seed xfce4,gdm,xubuntu-gdm-them,xubuntu-artwork

Sudo apt-get install qemu debootrap

Setup Our System

Change Root:cd /home/student/rootfssudo chroot .

Add two peremeter to /etc/apt/sources.list: universe multiverse

Update repository and install mplayer:apt-get updateapt-get install mplayer

Write Your First ARM Program with

Cross-compiler寫你的第一支 ARM 程式

CompilerCompiler

Source CodeSource Code

ProgramProgram

void main(){ ...} Binary

Eg, gcc

How to compile

Compile directly:

gcc -o example example.c

*.c *.c *.c *.c *.c *.c

*.o *.o *.o*.o *.o *.o*.o *.o

ProgramProgramCompile Process

Machine code

Link

X86X8632bits32bits

ARMARM32bits32bits

X86X8664bits64bitsIA64IA64 ARCARC

32bits32bits

ARMARM32bits32bits

NEONNEONPowerPCPowerPC

32bits32bits

AlphaAlpha32bits32bits

X86X8664bits64bits

AMD64AMD64

MIPSMIPS32bits32bits

MoreMoreX bitsX bits

MoreMoreX bitsX bits

MoreMoreX bitsX bits

MoreMoreX bitsX bitsMoreMore

X bitsX bits

fred@Fred-Debian:~$ fred@Fred-Debian:~$ cat /proc/cpuinfocat /proc/cpuinfoprocessorprocessor : 0: 0vendor_idvendor_id : GenuineIntel: GenuineIntelcpu familycpu family : 6: 6modelmodel : 23: 23model namemodel name : Intel(R) Core(TM)2 Duo CPU U9400 @ 1.40GHz: Intel(R) Core(TM)2 Duo CPU U9400 @ 1.40GHzsteppingstepping : 6: 6cpu MHzcpu MHz : 800.000: 800.000cache sizecache size : 3072 KB: 3072 KBphysical idphysical id : 0: 0siblingssiblings : 2: 2core idcore id : 0: 0cpu corescpu cores : 2: 2apicidapicid : 0: 0initial apicidinitial apicid: 0: 0fdiv_bugfdiv_bug : no: nohlt_bughlt_bug : no: nof00f_bugf00f_bug : no: nocoma_bugcoma_bug : no: nofpufpu : yes: yesfpu_exceptionfpu_exception : yes: yescpuid levelcpuid level : 10: 10wpwp : yes: yesflagsflags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl vmx smx est sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 lahf_lm ida tpr_shadow vnmi flexprioritytm2 ssse3 cx16 xtpr pdcm sse4_1 lahf_lm ida tpr_shadow vnmi flexprioritybogomipsbogomips : 2793.05: 2793.05clflush sizeclflush size : 64: 64cache_alignmentcache_alignment : 64: 64address sizesaddress sizes : 36 bits physical, 48 bits virtual: 36 bits physical, 48 bits virtual

How About your System?

fred@Fred-Debian:~$ fred@Fred-Debian:~$ ls -l /bin/lsls -l /bin/ls-rw-rwxxr-r-xxr-r-xx 1 root root 91728 2010-03-06 21:23 /bin/ls 1 root root 91728 2010-03-06 21:23 /bin/ls

fred@Fred-Debian:~$ fred@Fred-Debian:~$ file /bin/lsfile /bin/ls/bin/ls: /bin/ls: ELF 32-bitELF 32-bit LSB executable, LSB executable, Intel 80386Intel 80386, version 1 , version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, stripped2.6.18, stripped

NOTE: NOTE: ELF 32-bitELF 32-bit LSB executable, LSB executable, ARMARM, version 1 (SYSV), , version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.16, dynamically linked (uses shared libs), for GNU/Linux 2.6.16, strippedstripped

How to know format of binary file

fred@Fred-Debian:~$ fred@Fred-Debian:~$ ldd /bin/lsldd /bin/lslinux-gate.so.1 => (0xb7896000)linux-gate.so.1 => (0xb7896000)libselinux.so.1 => libselinux.so.1 => /lib/libselinux.so.1/lib/libselinux.so.1 (0xb7862000) (0xb7862000)librt.so.1 => librt.so.1 => /lib/i686/cmov/librt.so.1/lib/i686/cmov/librt.so.1 (0xb7859000) (0xb7859000)libacl.so.1 => libacl.so.1 => /lib/libacl.so.1/lib/libacl.so.1 (0xb7851000) (0xb7851000)libc.so.6 => libc.so.6 => /lib/i686/cmov/libc.so.6/lib/i686/cmov/libc.so.6 (0xb770a000) (0xb770a000)libdl.so.2 => libdl.so.2 => /lib/i686/cmov/libdl.so.2/lib/i686/cmov/libdl.so.2 (0xb7706000) (0xb7706000)/lib/ld-linux.so.2 (0xb7897000)/lib/ld-linux.so.2 (0xb7897000)libpthread.so.0 => libpthread.so.0 => /lib/i686/cmov/libpthread.so.0/lib/i686/cmov/libpthread.so.0

(0xb76ed000)(0xb76ed000)libattr.so.1 => libattr.so.1 => /lib/libattr.so.1/lib/libattr.so.1 (0xb76e8000) (0xb76e8000)

Check all Shared libs

fred@Fred-Debian:~$ fred@Fred-Debian:~$ gcc -vgcc -vUsing built-in specs.Using built-in specs.Target: i486-linux-gnuTarget: i486-linux-gnuConfigured with: ../src/configure -v --with-pkgversion='Debian Configured with: ../src/configure -v --with-pkgversion='Debian 4.4.3-5' --with-bugurl=file:///usr/share/doc/gcc-4.4.3-5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c+4.4/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared --enable-multiarch --enable-+ --prefix=/usr --enable-shared --enable-multiarch --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-plugin --enable-clocale=gnu --enable-libstdcxx-debug --enable-plugin --enable-objc-gc --enable-targets=all --with-arch-32=i486 --with---enable-objc-gc --enable-targets=all --with-arch-32=i486 --with-tune=generic --enable-checking=release tune=generic --enable-checking=release --build=i486-linux---build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnugnu --host=i486-linux-gnu --target=i486-linux-gnuThread model: posixThread model: posixgcc version 4.4.3 (Debian 4.4.3-5)gcc version 4.4.3 (Debian 4.4.3-5)

Compiler Flags

Cross-CompilerCross-Compiler

Source CodeSource Code

ProgramProgram

void main(){ ...} Binary for Other platforms

Eg, arm-linux-gnueabi-gcc

gcc -mcpu=cortex-a8 -mfpu=vfp -mfloat-abi=softfpgcc -mcpu=cortex-a8 -mfpu=vfp -mfloat-abi=softfpgcc -mcpu=cortex-a8 -mfpu=neongcc -mcpu=cortex-a8 -mfpu=neon......

Compiler options for Platforms

Optimization with NEON intrinsics

Accelerate multimedia and signal processing algorithms

Video/Audio encode/decode

2D/3D graphic

Gaming

Working on 64 or 128 bit register in parallel

void reference_convert (uint8_t * __restrict dest, uint8_t * __restrict src, int n)void reference_convert (uint8_t * __restrict dest, uint8_t * __restrict src, int n){{ int i;int i; for (i=0; i<n; i++) {for (i=0; i<n; i++) { int r = *src++; // load redint r = *src++; // load red int g = *src++; // load greenint g = *src++; // load green int b = *src++; // load blue int b = *src++; // load blue

// build weighted average:// build weighted average: int y = (r*77)+(g*151)+(b*28);int y = (r*77)+(g*151)+(b*28);

// undo the scale by 256 and write to memory:// undo the scale by 256 and write to memory: *dest++ = (y>>8);*dest++ = (y>>8); }}}}

Reference Implementation in C

15.1 cycles per pixel.

void neon_convert (uint8_t * __restrict dest, uint8_t * __restrict src, int n)void neon_convert (uint8_t * __restrict dest, uint8_t * __restrict src, int n){{ int i;int i; uint8x8_t rfac = uint8x8_t rfac = vdup_n_u8vdup_n_u8 (77); (77); uint8x8_t gfac = uint8x8_t gfac = vdup_n_u8vdup_n_u8 (151); (151); uint8x8_t bfac = uint8x8_t bfac = vdup_n_u8vdup_n_u8 (28); (28); n/=8;n/=8;

for (i=0; i<n; i++) {for (i=0; i<n; i++) { uint16x8_t temp;uint16x8_t temp; uint8x8x3_t rgb = vld3_u8 (src);uint8x8x3_t rgb = vld3_u8 (src); uint8x8_t result;uint8x8_t result;

temp = temp = vmull_u8vmull_u8 (rgb.val[0], rfac); (rgb.val[0], rfac); temp = temp = vmlal_u8vmlal_u8 (temp,rgb.val[1], gfac); (temp,rgb.val[1], gfac); temp = temp = vmlal_u8vmlal_u8 (temp,rgb.val[2], bfac); (temp,rgb.val[2], bfac);

result = result = vshrn_n_u16vshrn_n_u16 (temp, 8); (temp, 8); vst1_u8vst1_u8 (dest, result); (dest, result); src += 8*3;src += 8*3; dest += 8;dest += 8; }}}}

Optimization with NEON intrinsics

9.9 cycles per pixel.

160: f46a040f vld3.8 {d16-d18}, [sl]160: f46a040f vld3.8 {d16-d18}, [sl] 164: e1a0c005 mov ip, r5164: e1a0c005 mov ip, r5 168: ecc80b06 vstmia r8, {d16-d18}168: ecc80b06 vstmia r8, {d16-d18} 16c: e1a04007 mov r4, r716c: e1a04007 mov r4, r7 170: e2866001 add r6, r6, #1 ; 0x1170: e2866001 add r6, r6, #1 ; 0x1 174: e28aa018 add sl, sl, #24 ; 0x18174: e28aa018 add sl, sl, #24 ; 0x18 178: e8bc000f ldm ip!, {r0, r1, r2, r3}178: e8bc000f ldm ip!, {r0, r1, r2, r3} 17c: e15b0006 cmp fp, r617c: e15b0006 cmp fp, r6 180: e1a08005 mov r8, r5180: e1a08005 mov r8, r5 184: e8a4000f stmia r4!, {r0, r1, r2, r3}184: e8a4000f stmia r4!, {r0, r1, r2, r3} 188: eddd0b06 vldr d16, [sp, #24]188: eddd0b06 vldr d16, [sp, #24] 18c: e89c0003 ldm ip, {r0, r1}18c: e89c0003 ldm ip, {r0, r1} 190: eddd2b08 vldr d18, [sp, #32]190: eddd2b08 vldr d18, [sp, #32] 194: f3c00ca6 vmull.u8 q8, d16, d22194: f3c00ca6 vmull.u8 q8, d16, d22 198: f3c208a5 vmlal.u8 q8, d18, d21198: f3c208a5 vmlal.u8 q8, d18, d21 19c: e8840003 stm r4, {r0, r1}19c: e8840003 stm r4, {r0, r1} 1a0: eddd3b0a vldr d19, [sp, #40]1a0: eddd3b0a vldr d19, [sp, #40] 1a4: f3c308a4 vmlal.u8 q8, d19, d201a4: f3c308a4 vmlal.u8 q8, d19, d20 1a8: f2c80830 vshrn.i16 d16, q8, #81a8: f2c80830 vshrn.i16 d16, q8, #8 1ac: f449070f vst1.8 {d16}, [r9]1ac: f449070f vst1.8 {d16}, [r9] 1b0: e2899008 add r9, r9, #8 ; 0x81b0: e2899008 add r9, r9, #8 ; 0x8 1b4: caffffe9 bgt 1601b4: caffffe9 bgt 160

Assembly output

convert_asm_neon:convert_asm_neon:

# r0: Ptr to destination data# r0: Ptr to destination data # r1: Ptr to source data# r1: Ptr to source data # r2: Iteration count:# r2: Iteration count:

push push {r4-r5,lr} {r4-r5,lr} lsr r2, r2, #3lsr r2, r2, #3

# build the three constants:# build the three constants: mov r3, #77mov r3, #77 mov r4, #151mov r4, #151 mov r5, #28mov r5, #28 vdup.8 d3, r3vdup.8 d3, r3 vdup.8 d4, r4vdup.8 d4, r4 vdup.8 d5, r5vdup.8 d5, r5

NEON and Assembler

2.0 cycles per pixel.

.loop:.loop:

# load 8 pixels:# load 8 pixels: vld3.8 {d0-d2}, [r1]!vld3.8 {d0-d2}, [r1]!

# do the weight average:# do the weight average: vmull.u8 q3, d0, d3vmull.u8 q3, d0, d3 vmlal.u8 q3, d1, d4vmlal.u8 q3, d1, d4 vmlal.u8 q3, d2, d5vmlal.u8 q3, d2, d5

# shift and store:# shift and store: vshrn.u16 d6, q3, #8vshrn.u16 d6, q3, #8 vst1.8 {d6}, [r0]!vst1.8 {d6}, [r0]!

subs r2, r2, #1subs r2, r2, #1 bne .loopbne .loop

pop { r4-r5, pc }pop { r4-r5, pc }

void neon_convert (uint8_t * __restrict dest, uint8_t * __restrict src, int n)void neon_convert (uint8_t * __restrict dest, uint8_t * __restrict src, int n){{ int i;int i; uint8x8_t rfac = uint8x8_t rfac = vdup_n_u8vdup_n_u8 (77); (77); uint8x8_t gfac = uint8x8_t gfac = vdup_n_u8vdup_n_u8 (151); (151); uint8x8_t bfac = uint8x8_t bfac = vdup_n_u8vdup_n_u8 (28); (28); n/=8;n/=8;

for (i=0; i<n; i++) {for (i=0; i<n; i++) { uint16x8_t temp;uint16x8_t temp; uint8x8x3_t rgb = vld3_u8 (src);uint8x8x3_t rgb = vld3_u8 (src); uint8x8_t result;uint8x8_t result;

temp = temp = vmull_u8vmull_u8 (rgb.val[0], rfac); (rgb.val[0], rfac); temp = temp = vmlal_u8vmlal_u8 (temp,rgb.val[1], gfac); (temp,rgb.val[1], gfac); temp = temp = vmlal_u8vmlal_u8 (temp,rgb.val[2], bfac); (temp,rgb.val[2], bfac);

result = result = vshrn_n_u16vshrn_n_u16 (temp, 8); (temp, 8); vst1_u8vst1_u8 (dest, result); (dest, result); src += 8*3;src += 8*3; dest += 8;dest += 8; }}}}

Optimization with NEON intrinsics

Optimizations with Compiler

Analyze Source code

Logic Optimization

Optimize with specific hardware (NEON...etc)

How to use Cross-compiler

Compile directly:

arm-linux-gnueabi-gcc -o example example.c

Development without Real

Hardware在模擬器上開發

Get and compile QEMU

Download The Source Code

wget http://qemu-omap3.googlecode.com/files/qemu-omap3-v0.01.tar.bz2

tar jxvf qemu-omap3-v0.01.tar.bz2

cd qemu-omap3

Build qemu-omap3

./configure --target-list=arm-softmmu

make

Download and Configure

Download u-boot/kernel/rootfs

● cd arm-softmmu

● wget http://qemu-omap3.googlecode.com/files/image-v0.01.tar.bz2

● tar jxvf image-v0.01.tar.bz2

● wget http://beagleboard.googlecode.com/files/rd-ext2-8M.bin

Generate nand flash image

● dpkg-reconfigure dash

Generate images

Generate u-boot/kernel/rootfs

● cp ../bb_nandflash.sh .

● cp ../bb_nandflash_ecc .

● ./bb_nandflash.sh x-load.bin.ift beagle-nand.bin x-loader

● ./bb_nandflash.sh u-boot.bin beagle-nand.bin u-boot

● ./bb_nandflash.sh uImage beagle-nand.bin kernel

● ./bb_nandflash.sh rd-ext2-8M.bin beagle-nand.bin rootfs

● ./bb_nandflash_ecc beagle-nand.bin 0x0 0xe80000

Run QEMU

Run with commands:

./qemu-system-arm -M beagle -mtdblock beagle-nand.bin

Using Ctrl-Alt-3 to switch to serial port (uboot)● nand read 0x80000000 0x280000 0x400000

● nand read 0x81600000 0x680000 0x800000

● setenv bootargs 'console=ttyS2,115200n8 ramdisk_size=8192 root=/dev/ram0 rw rootfstype=ext2 initrd=0x81600000,8M nohz=0ff'

● bootm 0x80000000