ememu

'ememu' is EMbedded system EMUlator written by Java.

Requires

• Java 7 or later

Supported Systems

• ARM Versatile AB/PB
  • CPU: ARM926EJ-S
    • Supported: ARM, Thumb
    • Not yet: EE, VFP, Jazelle
  • Devices: Timer, UART, NAND
  • Not yet: Ethernet, LCD, eMMC, and so on...
  • OS: Linux 4.1.x, Linux 3.18.x, Linux 3.14.x, Linux 3.12.x
    • 3.12.x: Need to enable CONFIG_EABI if you want to use recently cross-compiler.

Live DEMO

You can run the ememu (applet version) on my WEB site.

http://www.katsuster.net/contents/java/ememu/ememu_applet.html

How to use

Get the Cross-Compiler

Download the cross-compiler for ARM.

For example:

• Mentor Graphics(CodeSourcery): http://www.mentor.com/embedded-software/sourcery-tools/sourcery-codebench/overview/
• Linaro: http://www.linaro.org/downloads/
  • WARNING: Linaro's toolchain glibc includes Thumb-2 instructions. The ememu does not support Thmub-2 instructions yet...
• From Scratch: http://www.katsuster.net/contents/java/ememu/ememu.html
  • NOTE: If you want to know how to build these toolchains, please see 'crosstool-builder' repository of my github.
  • https://github.com/katsuster/crosstool-builder

Cross-compile the Linux kernel

Set the default config of ARM Versatile.

$ export ARCH=arm
$ export CROSS_COMPILE=/path/to/cross-compiler/arm-2013.11/bin/arm-none-linux-gnueabi-
$ cd linux
$ make KBUILD_DEFCONFIG=versatile_defconfig defconfig

Change the configs as you need.

$ make menuconfig

And build.

$ make -j4

Linux kernel image file is created on the linux/arch/arm/boot/Image directory.

Cross-compile the Busybox

Set the build configs to build a static binary.

$ export ARCH=arm
$ export CROSS_COMPILE=/path/to/cross-compiler/arm-2013.11/bin/arm-none-linux-gnueabi-
$ cd busybox
$ make menuconfig
Busybox Settings  --->
  Build Options  --->
    [*] Build BusyBox as a static binary (no shared libs)

And build.

$ make -j4

Busybox executable file is created on the busybox/ directory.

Create the InitramFS Image

First, create directories as follows. NOTE: dev/console, dev/null, dev/ttyXX are the device files. To create device files, please see the manual of 'mknod' command.

initramfs
|-- bin
|   |-- [ -> busybox
|   |-- ] -> busybox
...
|-- dev
|   |-- console
|   |-- null
|   |-- tty
...
|-- etc
|-- init
|-- lib
|-- proc
|-- run
|-- sbin
`-- sys

Next, convert and compress these directories to the InitramFS.

$ cd initramfs
$ find . | cpio --format=newc -o > ../initramfs.cpio
$ cat ../initramfs.cpio | gzip  > ../initramfs.gz

Build the Emulator

Build the emulator using Apache Ant.

$ cd ememu
$ ant

JAR file is created on ememu/emu/ant/dist directory.

Run the Emulator

Run the emulator (console version) on the Windows Command Prompt or some of Linux terminal as you like.

$ java -jar emu/ant/dist/armemu.jar linux/arch/arm/boot/Image initramfs.gz
Exception: Reset by 'Init.'.
loadFile: linux/arch/arm/boot/Image
loadFile: 'linux/arch/arm/boot/Image' done, 3912832bytes.
loadFile: initramfs.gz
loadFile: 'initramfs.gz' done, 1113270bytes.
...

Known BUGS

• The emulator has crashed when execute the thumb instructions. For example, glibc of Linaro cross compiler includes thumb instructions.

FAQ

Sorry, not yet...