Article View: comp.sys.atari.st
Article #34258Re: Register saving for BIOS traps?
From: Simon Poole
Date: Sun, 25 Sep 1988 20:20
Date: Sun, 25 Sep 1988 20:20
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In article <19880922163903.5.JRD@MOA.SCRC.Symbolics.COM> jrd@STONY-BROOK.SCRC.SYMBOLICS.COM (John R. Dunning) writes: ..... >I believe it's necessary to save (some) registers around BIOS and XBIOS >traps. The question for today is: which ones? Is there any rhyme or >reason to which registers get trashed inside the trap? D0-D2 and A0-A2, reason: they aren't saved by the trap handler, but are used by the calls, why Atari decided not to save all regs they use is a mystery to me (the calls are so slow just because they save nearly everthing, it seems a shame they didn't do it all). >A related question; am I correct in assuming that GEMDOS traps don't >require register saving? I wouldn't count on that, suposedly D0 and A0 get zapped (I don't have the official Atari doc's lying around here, but I'll check on Monday). -- ---------------------------------------------------------------------------- UUCP: ...mcvax!cernvax!forty2!poole Simon Poole BITNET: K538915@CZHRZU1A ----------------------------------------------------------------------------
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!mcvax!cernvax!ethz!forty2!poole From: poole@forty2.UUCP (Simon Poole) Newsgroups: comp.sys.atari.st Subject: Re: Register saving for BIOS traps? Message-ID: <469@forty2.UUCP> Date: 25 Sep 88 20:20:18 GMT References: <19880922163903.5.JRD@MOA.SCRC.Symbolics.COM> Reply-To: poole@forty2.UUCP (Simon Poole) Organization: Exp. Physics University Zuerich Lines: 22