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From: "Rod Pemberton" <buzz@notnotnontnooatno.cmm>
Newsgroups: comp.lang.forth
Subject: Re: Static Single Assignment form to Stack allocation
Date: Sat, 07 Feb 2015 21:10:42 -0500
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On Sat, 07 Feb 2015 21:04:07 -0500, Rod Pemberton  
<buzz@notnotnontnooatno.cmm> wrote:
> On Sat, 07 Feb 2015 17:51:57 -0500, Aliaksei Chapyzhenka  
> <alex.drom@gmail.com> wrote:

>> : DROP DUP XOR XOR ;
>
> That doesn't do what you think it does.  DUP creates two stack
> items.  XOR XOR converts one of them to zero.  But, you still
> have two items on the stack, the second one being a zero.
> DROP needs to _reduce_ the number of items on the stack.
> Reducing or increasing the number of items on a stack usually
> requires a "primitive" or low-level Forth word or operation.
>

Correction.  Scratch that.  That was two XOR's.  One item.


Rod Pemberton