[comp.unix.wizards] br & cvec

alo@kampi.hut.fi (Antti Louko) (03/22/89)

What are the reasons for using registers r11 (br) and r10 (cvec) as
global variables in the probe routines of VAX-BSD device-drivers.
I think there must be some historical reasons for this practise.

For example, Ultrix uses global variables for the same purpose.

chris@mimsy.UUCP (Chris Torek) (03/22/89)

In article <20718@santra.UUCP> alo@kampi.hut.fi (Antti Louko) writes:
>What are the reasons for using registers r11 (br) and r10 (cvec) as
>global variables in the probe routines of VAX-BSD device-drivers.
>I think there must be some historical reasons for this practise.

Probably the original authors of autoconf (?<someone whose name I have
forgotten> and Michael C. Toy) just liked it that way.  4.4BSD will
probably use global variables.  (The source on okeeffe currently uses
both globals and r11/r10.  Yech.)
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In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
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