NVAX and NVAX+: single-chip CMOS VAX microprocessors

A description is given of NVAX and NVAX+, single-chip microprocessors that implement Digital Equipment Corporation's VAX architecture. Pipelining techniques that have traditionally been associated with RISC CPUs are used to greatly improve the performance of these chips over previous VAX microprocessors. Successful application of these techniques requires careful consideration of memory request and operand request ordering, I/O space access, and multiprocessor issues. NVAX provides an upgrade path to customers having existing systems which use a previous VAX microprocessor. NVAX+ provides a migration path to customers who choose to convert NVAX+ systems to use the DECchip 21064 ALPHA microprocessor.<<ETX>>