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- From: SYSMGR@IPG.PH.KCL.AC.UK
- Newsgroups: vmsnet.internals
- Subject: re: UNEXPECTED SYSTEM SERVICE EXCEPTION
- Message-ID: <53C00375_00057EE8.0095E4E079DCABC0$6_1@UK.AC.KCL.PH.IPG>
- Date: Wed, 29 JUL 92 16:00:33 BST
- Organization: Macro32<==>Vmsnet.Internals Gateway
- X-Gateway-Source-Info: Mailing List
- Lines: 23
-
- > I got an Unexpected system service exception with only 3 args, the
- > pc of which was HALFWAY through an instruction. Anyone ever seen
- > something like this (bug$_wslenotvalid)???
-
- Haven't seen anything like these details, but have seen PC halfway through
- an instruction. It's called a phase error. What I had done was CALL a JSB
- entrypoint. The first two bytes of the first instruction were a valid
- save mask, so it carried on. The third byte was also a valid instruction...
- Normally, things go wrong pretty fast thereafter.
-
- Interesting irrelevance: the genetic code (DNA base sequences) has a lot
- in common with a computer program. It has been observed that two genes
- (programs for assembling proteins) can share a common sequence WITH A
- PHASE SHIFT BETWEEN THEM. It could be fun trying to write a MACRO
- equivalent : maybe a piece of code that did one sensible thing if you
- JSB'ed it and a totally different sensible thing if you CALLed it!
-
- Nigel Arnot
-
- NRA%ipg.ph.kcl.ac.uk@nsfnet-relay.ac.uk (internet)
- NRA%uk.ac.kcl.ph.ipg@ukacrl.bitnet (bitnet)
- etc...
-
-