Date: Thu, 12 Sep 1996 08:37:16 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, dyson@dyson.iquest.net Cc: current@FreeBSD.ORG, dg@Root.COM, kato@eclogite.eps.nagoya-u.ac.jp Subject: Re: patch for Cyrix/Ti 486SLC/DLC CPU bug Message-ID: <199609112237.IAA13505@godzilla.zeta.org.au>
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>>[invlpg] >It is unreasonable (IMO) but unavoidable if the system doesn't provide >a needed service. It is difficult to imagine a machine independent >reason to do a pmap_update (but I guess that it might be possible.) >So, to kind-of answer your comment -- I will put it in cpufunc, but >the only module that should normally need it would be pmap.c??? cpufunc was supposed to be for "access to special i386 instructions". It is now clear that the right way to do this is usually to encapsulate _single_ instructions in inline functions and write C code to combine the functions. The instructions are very machine-dependent and shouldn't be given sortof-machine-independent names. There are several exceptions to this: disable_intr()/enable_intr(): should be named cli()/sti() and maybe renamed in another layer. ffs()/fls(): machine-independent interface; implement in another file. (Only) machine-dependent implementations as inline functions of machine-independent interfaces need to be included in <systm.h>. loadandclear(): the primitive should be xchgl(). PC98 i/o functions: should never have been here. cpufunc.h is supposed to have only i386 primitives. pmap_update(): should be built out of primitives to read and write %cr3. Primitives to access other %cr's might as well be here too. At least ddb should be able to display and set them all; however, perhaps this should be implemented by having extern functions for all the cpu primitives - then the debugger wouldn't need special code for them. I'd like to do this using compiler magic - perhaps use a file cpufunc.c that just #includes cpufunc.h, and compile it with -fkeep-inline-functions. Names for read/write/rd/wr/r/w/load/store should be more consistent. setbits(): should be named orl(). Bruce
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