I'm afraid you're confused, Tom; Macs use Motorola's PowerPC CPUs, which are a licensed implementation of IBM's POWER architecture. SPARC (Scaleable Processor ARChitecture) is an architecture developed by Sun Microsystems and Fujitsu, and has been the basis of the Sun's primary lines of workstations and servers since 1987. The design is now controlled by the non-profit
SPARC International (it is also standardized as IEEE 1754-1994), and can implemented royalty-free by any who wish to (though they do request a $99 registration fee to support the organization). They also offer memberships to companies and organizations that want to get greater support form them; embership fees for range from $100 for an academic membership (i.e., a university) up to $75000 for a seat on the executive board. Considering the costs involved in implementing a CPU design like this, the fees are negligible, especially compared to what licensing most other architectures would cost.
Aside from the SPARC Intl. website, the logical place to start looking for information is at
Sun's web site. For example, you can download the
SPARC Assembly Language Reference Manual as a PDF there. A bit of digging should find plenty of similar prizes.
There is a
SPARC-based Linux (available from most of the major distributions, as well as a few specific to the Sun systems), and that would indeed be a place to find some code examples. There are also ports of
FreeBSD,
NetBSD,
Minix,
Xinu. Also, in addition to Solaris, there are some open-source OSes (mostly experimental) that were originally implemented on SPARCs, such as
Amoeba,
Chorus and
MythOS.
While I was looking all this up, I stumble on this page:
Writing an Operating System for the SunServer. Looks like just the sort of reference you wanted, doesn't it? It's fairly limited, but it may help a bit. This article on
OS portability may be helpful as well. HTH.