Article View: comp.sys.amiga.tech
Article #12003Why 6 bytes between pointe to functions in *Base
From: Andy Heffernan
Date: Wed, 29 Mar 1989 04:10
Date: Wed, 29 Mar 1989 04:10
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1475 bytes
Someone else will slip this in before me, but I'm a weasel.
In article <2486@scolex.sco.COM> brianm@sco.COM (Brian Moffet) writes:
> I noticed the other day that the distance between shared
> library functions is 6 bytes. The is at an offset less than
> the base of the Shared Library pointer. I would like to know,
> why 6 bytes? 4 of these bytes should be the pointer itself,
> but what are the other 2? flags?
They are the 680x0 JMP instruction, $4EF9.
You do a lib call with something like:
jsr $fdd8(a6)
which lands you into your jump table.
From there, this:
jmp $2032ea
will get you to your library function.
Empiricism is fun, no?
> Brian Moffet {uunet,decvax!microsoft,ucscc}!sco!brianm
> -or- ...sco!alar!brian
A.Heffernan, weasel-at-large
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Andy Heffernan uunet!glyph!nichiren [1222 - 1282]
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!glyph!nichiren From: nichiren@glyph.UUCP (Andy Heffernan) Newsgroups: comp.sys.amiga.tech Subject: Why 6 bytes between pointe to functions in *Base Keywords: Pointer and Flags??? Message-ID: <0286.AA0286@glyph> Date: 29 Mar 89 04:10:41 GMT References: <2486@scolex.sco.COM> Followup-To: comp.sys.amiga.tech Distribution: na Organization: Eh? Lines: 28