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From: chrisg@cbmvax.commodore.com (Chris Green)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Help with language writing
Message-ID: <21765@cbmvax.commodore.com>
Date: 21 May 91 13:28:30 GMT
References: <1991May20.134453.15378@Daisy.EE.UND.AC.ZA>
Reply-To: chrisg@cbmvax.commodore.com (Chris Green)
Distribution: all
Organization: Commodore, West Chester, PA
Lines: 24

In article <1991May20.134453.15378@Daisy.EE.UND.AC.ZA> mlaidlaw@Daisy.EE.UND.AC.ZA (Mike Laidlaw) writes:
>
>Help!
>
>I'm writing a Forth-like language and am stuck.My problem is this,when
>creating secondarys using the outer interpreter (editor) I am using absolute
>memory jumps to primitives or other secondarys.I then save the dictionary to
>disk as a straight memory dump.When I next load my language,AllocMem gives
>me memory starting at a different address thus when I load my program,all the
>absolute calls are incorrect thus my program bombs.

	JForth uses a variety of techniques for this. When generating a call to
another routine, they use a 16 bit relative branch to get to it, if possible.
If not, they generate a JSR xxx(A4) where A4 is a register that points 32k into
the image. If even this doesn't reach, then they generate a jsr absolute to
the target address, and add this address to an internal list of absolute addresses
which must be relocated at load time.
-- 
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|Chris Green - Graphics Software Engineer   - chrisg@commodore.COM      f
|                  Commodore-Amiga          - uunet!cbmvax!chrisg       n
|My opinions are my own, and do not         - killyouridolssonicdeath   o
|necessarily represent those of my employer.- itstheendoftheworld       r
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