please pull powerpc.git 'merge' branch
Arnd Bergmann
arnd at arndb.de
Sun Apr 30 21:42:01 EST 2006
On Sunday 30 April 2006 06:20, Olof Johansson wrote:
> We already have SMT, ICACHE_SNOOP and ALTIVEC feature bits, so it probably
> makes sense to stay in the ARCH_2_05 direction. Unfortunately it might
> be tricky to rename the old defines now due to userland exposure.
>
> I guess Cell breaks all this logic though. Which PPC base version does
> it implement?
The Cell Broadband Engine Architecture in theory is 2.03 and also mandates
some of the extensions that are optional in there.
The relevant sections in the specs are:
| 4.1.1 Optional Features in PowerPC Architecture, Book I (Required for
| CBEA)
| The following facilities and instructions are considered optional in
| the PowerPC Architecture, but are required for the PPE by the CBEA
| user mode environment.
| • Floating reciprocal estimate single A-form (fres)
| • Floating reciprocal square-root estimate A-form (frsqte)
| • Vector/SIMD multimedia extension
| Note: The optional PowerPC floating-point instructions that are
| mandatory in the CBEA are needed for the application space targeted
| by the CBEA.
|
| 4.1.3 Optional Features in PowerPC Architecture, Book II (Required
| for CBEA)
| The following facilities and instructions are considered optional
| in the PowerPC Architecture, but are required in the CBEA.
| • Data cache block touch X-form (dcbt)
| This is an optional version of dcbt that permits a program to
| provide a hint that a sequence of data cache blocks is likely
| to be needed soon.
| Book II describes these facilities and instructions.
I believe the actual implementation is missing one of the mandatory
features of 2.03 that was not in 2.02 though.
Arnd <><
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