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Ah, thank you! I would have never thought to search under that name. It makes sense for such a non-mainstream architecture, but I wish there were (even reverse-
by nxobject 2y ago
Ah, thank you! I would have never thought to search under that name. It makes sense for such a non-mainstream architecture, but I wish there were (even reverse-engineered) resources as well on "this is what the execution engine looks like". There are instructions there that clearly scream "very extensive microcoding is going on here", e.g. vintage EBCDIC/BCD conversion, string/stream instructions, control channel supervision, etc.
- ruslan 2y agoIt seems to me the mentioned "Principles of Operation" document describes a virtal machine compatible with good old System/370 what's now known as IBM z/Architecture. But the Telum CPU itself runs on Power10 cores or alike RISCs.
- rbanffy 2y agoNo. The cores are not POWER10 at all. While there is a ton of microcode and interception magic happening (and nothing but the hypervisor, PR/SM IIRC, runs on metal - the hypervisor exposes partitions to the zVM environment) the cores are still very different from POWER and run their own s390x ISA. You might be confusing it with the AS/400 CISC ISA, which exists as an emulation layer on top of POWER, since all IBMi machines are almost identical to their POWER counterparts.
- sillywalk 2y agoThere isn't an emulation layer for AS/400 though, it's native POWER code. The AS/400 / 'i' are descendants of the System/38 and implement a "Technology Independent Machine Interface". Applications target this high-level interface, rather than the underlying hardware. Before first run (or when they're installed?) applications get compiled from abstract Machine Interface code to native code.