# Download and Install Virtual Box
https://www.virtualbox.org/

# Download this Ubuntu 10.04 RaspberryPi VM image
# (this is NOT the RISC emulator)
# wget RaspberryPi.VirtualBox.zip
wget http://rpi.descartes.co.uk/sim-emu/RaspberryPi.VirtualBox.zip

# Load the image into Virtual Box 
# through the "Import Appliance" menu

# Start the RaspberryPi Ubuntu VM
# Login with: rpi/password

# Open the LXTerminal

# Install ssh
ub-shell> sudo apt-get install ssh

# Download the debian6.tar.gz QEMU ARMv6 image
ub-shell> wget http://rpi.descartes.co.uk/sim-emu/debian6.tar.gz

# Unpack the image
ub-shell> tar xvzf debian6.tar.gz

# Edit the startup script
# by inserting at end of command
# the following option:  -redir tcp:2222::22
ub-shell> cd debian6
ub-shell> vi launchDebian

# After editing, start the qemu emulator
ub-shell> ./launchDebian

# You can watch the startup by launching xtightvncviewer
# The server connection should be to 'localhost' or '127.0.0.1'
# You can log into this connection with 
# the username and password pi/suse,
# but I prefer a ssh terminal login.

# Networking seems to be off when running the qemu in a VirtualBox VM
# on top of the real host. I spent a short while trying to untangle 
# that nested mess before deciding to move on. TBD. Instead, download 
# the needed files on the Ubuntu VM and secure copy them to
# the Debian6 ARM emulator. 
# User and password: pi/suse.

# Also, the keyboard mapping is a bit off.
# I haven't looked into remapping yet. 
# For now, know that the quote _"_ maps to _@_

# wget openmpi-1.5.4.tar.bz2
ub-shell> wget http://www.open-mpi.org/software/ompi/v1.5/downloads/openmpi-1.5.4.tar.bz2
ub-shell> scp -P 2222 openmpi-1.5.4.tar.bz2 pi@localhost:

# Open a ssh terminal to the Debian6 emulator, 
# user and password: pi/suse 
ub-shell> ssh -p 2222 pi@localhost

# On the Debian6 ARMv6 emulator,
# Unpack the openmpi tarball
deb-shell> bunzip2 openmpi-1.5.4.tar.bz2
deb-shell> tar xvf openmpi-1.5.4.tar
deb-shell> cd openmpi-1.5.4

# You have to make 3 changes to the standard distribution
# 1) Delete all references to the RISC instruction 'dmb'
# 2) Modify the 'configure' file to include an 'armv6' option
# 3) Compile with CFLAGS=-march=armv6 

## 1) Using 'vi', make the following edits to these three files
deb-shell> vi ./opal/asm/generated/atomic-local.s
#	delete all dmb instructions
deb-shell> vi ./opal/asm/base/ARM.asm
#	delete all dmb instructions
deb-shell> vi ./opal/include/opal/sys/arm/atomic.h
#	change the lines:
		#if OPAL_WANT_SMP_LOCKS
			#define MB()  __asm__ __volatile__ ("dmb" : : : "memory")
			#define RMB() __asm__ __volatile__ ("dmb" : : : "memory")
			#define WMB() __asm__ __volatile__ ("dmb" : : : "memory")
		#else
			#define MB()
			#define RMB()
			#define WMB()
		#endif

#	to read:
			#define MB()
			#define RMB()
			#define WMB()
		
## 2) Using 'vi', 
# add the following to the 'configure' file at line 26946 of 171183
deb-shell> vi configure
# goto line 26946, 
# there should be an 'alpha-' section above 
# and an 'armv7' below
# insert the following
#        armv6*)
#            ompi_cv_asm_arch="ARM"
#            OPAL_ASM_SUPPORT_64BIT=0
#            OMPI_GCC_INLINE_ASSIGN='"mov %0, #0" : "=&r"(ret)'
#            ;;

## 3) compile and install with the following CFLAGS
deb-shell> CFLAGS=-march=armv6
deb-shell> ./configure CFLAGS=-march=armv6
deb-shell> make
deb-shell> sudo make install