There used to be a document on Sun's website that described the Sparc
v8plus ABI. This allowed the use of some 64-bit regs and some v9
However, the link I used to have is broken, and I can no longer find
any info about the v8plus ABI.
I'm mostly interested in figuring out what it used to say, and how it
changes the sigcontext and what 64-bit registers are preserved on a
context switch. (I think it was only the %o regs since the register
save area on the stack is only for 32-bit registers.)