sunset's gemlog

Almost an Embedded Itanium: ST200

During the period immediately before and immediately after the release of the "Merced" Itanium, HP and ST Micro had a close partnership around a new, programmer-friendly embedded CPU called ST200. While neither party ever emphasized the connection, ST200 has an undeniable similarity to Itanium, and one could probably make a strong case for it being an EPIC processor.

Some of the major similarities, from an examination of the ST231 manuals --

There are some significant ways they differ, too.

Itanium is dead, and ST2xx looks like it isn't far behind; ST announced in 2016 that they would exit the set-top box market, and I'm not sure if any part of ST's future roadmap includes ST2xx. It's interesting to see a likable, normal VLIW ISA in an embedded core, though, especially compared to bizarre instruction sets that exist elsewhere in the embedded VLIW space.[1]

[1] I'm referring to, among others, an 8-wide VLIW split into two halves, each with their own register file with limited cross-connect, and with almost no concessions to programmers expecting the familiar comforts of home; after all, a near-complete lack of pipeline interlocks builds character. The family will remain nameless to protect the guilty, but the truth is out there...