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From: UNBCIC@BRFAPESP.BITNET
Newsgroups: comp.lang.forth
Subject: Align
Message-ID: <9106272057.AA08598@ucbvax.Berkeley.EDU>
Date: 27 Jun 91 18:19:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: UNBCIC%BRFAPESP.BITNET@SCFVM.GSFC.NASA.GOV
Organization: The Internet
Lines: 39

=> In article <9106190432.AA02430@ucbvax.Berkeley.EDU>,
=> UNBCIC%BRFAPESP.BITNET@SCFVM.GSFC.NASA.GOV writes:
=>
=> '=>Further, `ALLOT' and `,' should align on
=> `=> CELL boundaries, and `C,' should ensure that the next invocation of
=> `=> `HERE', `ALLOT', `,' etc. will utilize a CELL boundary appropriate
=> `=> to the processor [mine].
=> `
=> `C, should ensure that the next invocation of HERE, ALLOT...will utilize a CE
   LL
=> `boundary?!?!?!?!??!?!?!? It's better live with a slow @ and ! than with this
   !
=> `We have only two options: 1) Throw an overhead upon HERE, ALLOT...; 2) Make
   C,
=> `ALLOT a CELL, thus actings a comma.

I was talking about options when you make C, ensure ....

=> There is a third option.  Put the onus on the _programmer_ to put
=> ALIGN after the appropriate ALLOT / C, when allocating a data
=> structure in the dictionary if it is possible that a partial cell has
=> been allotted.  Then use CELL+ and CHAR+ and ALIGNED when ``stepping
=> through'' the data structure.  That is the approach taken by ANS
=> Forth.

That's the way I like it. If someone wants a 83-Standard @ in a ANS-Forth just
type:
: @ DUP C@ SWAP 1+ C@ ( shift or multiply ) + ;
: ! 2DUP C! SWAP ( shift or divide ) SWAP 1+ C! ;

About C! a TRUE flag: I think that ANS Forth have adopted as TRUE all bits 1,
so C! should work.

                              (8-DCS)
Daniel C. Sobral                           Errare Humanum Est...
UNBCIC@BRFAPESP.BITNET                     ...Perseverare Autem Diabolicum
UNBCIC@FPSP.FAPESP.ANSP.BR
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