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Maintainer's Note on IBM Cell and PS3 systems
If you wish to run Debian on a PS3 or other IBM-Cell-based system, you should instead use the standard powerpc port. The "SPE" in the "powerpcspe" architecture does not refer to the "Synergistic Processing Element" units on IBM Cell microprocessors, although both are PowerPC variants. It instead refers to the "Signal Processing Engine" hardware present on low-power 32-bit FreeScale and IBM "e500" cores. See also http://lists.debian.org/debian-devel/2011/06/msg00592.html
Current status
The port idled for a while due to lack of manpower, and as a result several of the key transitions (multiarch libc, perl, etc) did not happen properly for the "powerpcspe" build servers. Kyle Moffett has been working on getting the port back up-to-date with current "wheezy", his progress can be tracked on his blog.
Current 'powerpcspe' bug list
PowerpcSPE specific type-handling
Repositories and Build Status
Hosting for the unofficial PowerPCSPE port is graciously provided by the wonderful people at debian-ports.org. In particular we'd like to thank Aurelien Jarno for his help getting everything set up.
Latest Statistics
Architecture summary
The 'powerpcspe' architecture is a binary-incompatible variant of the PowerPC/POWER designed and supported by FreeScale and IBM. It is also known under the trade names "e500"/"MPC8500" and "e200"/"MPC5xx".
Additional information can be found at:
Instruction set
In particular, the 'powerpcspe' architecture lacks the classic FPU with dedicated FPRs found on most other PowerPC systems. It is replaced with a set of "SPE" instructions which perform floating-point operations on the integer registers.
In an unfortunate choice of architecture design, the instructions used for the "SPE" operations overlap with those for the Altivec unit on most other modern PowerPC cores.
Chipset details
The "e500v2"-series chips have 64-bit GPRs, where the high 32-bits are accessible only via the special "SPE" instructions, allowing them to make efficient use of the "double" datatype.
The relatively rare "e500v1"-series chips have only 32-bit GPRs, and require software traps and emulation to support native "double".
The "e200z3" and "e200z6" chips have no support for floating point at all, but with software traps and emulation are binary-compatible with the "e500"-series chips.
GCC/EGLIBC considerations
The Debian port to this architecture specifically chooses to optimize for the higher-end chips (e500v2), as most of the others are targeted at automotive applications or no longer in production.
Current GCC 4.6.1 suffers from the following bugs:
PR50906: Stack unwind failure during exception handling in functions using E500 floating point.
Older versions of GCC suffered from the following bugs (which have all been resolved in the latest Debian packages):
PR44169: Most code using Thread Local Storage would be mis-compiled and crash when built with -O1.
PR44364: Upper half of 64-bit GPRs used by floating point and vector code did not always get saved on the stack before being overwritten.
PR44606: Writes to the lower half of 64-bit GPRs would cause an earlier write to the upper half to be completely discarded, resulting in math errors.
Full support for the e500v2 requires the following options to GCC's "configure":
--with-cpu=8548
--enable-e500_double
--with-long-double-128
Please note that the --with-long-double-128 is desired to match the behavior of long double on other PowerPC-based platforms. (Otherwise long double is exactly the same as double).
Installing the port
Get the debootstraped image. Currently debootstrapping is tricky because not all packages are in unstable. Once you have the image:
unpack the image as the root user with tar xjpf powerpcspe-debootstrap-root.tar.bz2 on your destination disk.
if it fails please verify the checksum of image using sha1sum.
- some versions of busybox's tar may choke on this image. Please consider using gnu tar in such a case.
- if you need a console on ttyS0:
edit etc/inittab and add a line like T0:23:respawn:/sbin/getty -L ttyS0 115200 vt100
make sure /dev/ttyS0 exist. Either install udev or use the following command mknod ttyS0 c 4 64
edit etc/apt/sources.list and enter a mirror from here which is close to you.
the password for root is root
This is a minimal environment in which you can boot into.
Final notes
At this time the 'powerpcspe' architecture port is still very much an unofficial port. While we hope that will change in the future, it is entirely possible that the embedded niche of the processor will make such an official Debian port problematic.