Alpha AXP architecture
Richard L. Sites · Communications of the ACM · 1993
SitesThus in all these cases the Romans did what all wise princes ought to do," namely, not only to look to all present troubles, but also to those in the future, against which they provided with the utmost prudence.--NICCOLO MACHIAVELLI, The Prince he Alpha AXP TM architecture grew out of a small task force chartered in 1988 to explore ways to preserve the VAX/VMS TM customer base through the 1990s.This group eventually came to the conclusion that a new RISC architecture would be needed before the turn of the century, primarily because 32-bit architectures will run out of address bits.Once we made the decision to pursue a new architecture, we shaped it to do much more than just observe the OpenVMS VAX TM customer base.This article discusses the architecture from a number of points of view.First, we draw the distinction between architecture and implementation, then state the overriding architectural goals.A number of key architectural decisions are derived directly from these goals.The key decisions are then discussed, to distinguish the Alpha AXP architecture from others.The remaining sections discuss the architecture in more detail, from data and instruction formats