Having written the SPARC64 compiler and runtime for Go (and the Solaris port), I assure you I know the difference between SPARC V8 and SPARC V9.
It appears that I have been mislead, back in 2005 when OpenSPARC was released somebody from Sun told me that LEON is based on OpenSPARC, and I haven't bothered to check since. It seems to be a completely different design (it even uses VHDL instead of Verilog). So I was very mistaken about LEON.
However, there have been other (embedded) SPARC V8 CPUs derived from OpenSPARC. I have worked on one myself (on the software side). This one was a very strange one because it only had two register windows (and the ABI didn't use register windows) and they disabled SMT.
This type of modification is extremely easy to do on SPARC because of the way 64-bit works. There are no separate execution modes, there's simply another set of flags that's affected by instructions. The conditional instructions chose which set of flags to use.
I really like SPARC, it's my favorite architecture.
It appears that I have been mislead, back in 2005 when OpenSPARC was released somebody from Sun told me that LEON is based on OpenSPARC, and I haven't bothered to check since. It seems to be a completely different design (it even uses VHDL instead of Verilog). So I was very mistaken about LEON.
However, there have been other (embedded) SPARC V8 CPUs derived from OpenSPARC. I have worked on one myself (on the software side). This one was a very strange one because it only had two register windows (and the ABI didn't use register windows) and they disabled SMT.
This type of modification is extremely easy to do on SPARC because of the way 64-bit works. There are no separate execution modes, there's simply another set of flags that's affected by instructions. The conditional instructions chose which set of flags to use.
I really like SPARC, it's my favorite architecture.