Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!willett!ForthNet
From: ForthNet@willett.UUCP (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: Optimization
Message-ID: <636.UUL1.3#5129@willett.UUCP>
Date: 9 Mar 90 00:52:31 GMT
Organization: Latest link in the ForthNet chain.  (Pgh, PA)
Lines: 47


 Date: 03-08-90 (01:53)              Number: 1777 (Echo)
   To: GENE CZARCINSKI               Refer#: 1564
 From: MIKE SPERL                      Read: NO
 Subj: OBK3501                       Status: PUBLIC MESSAGE

 Gene,

     The following illustrates the effect of new technology on 
 programming.  Changing the kernel would improve 2/386 perrformance 
 by 100%, while having minimal (stiill beneficiall) effect on 8088 
 performannce. 

 \ CODE 2*  ( n -- 2*n )         8088 286 386
 \                POP AX         \ 12, ?,, 7
 \                 SHL AX, # 1    \  2,,  , 3!
 \                1PUSH          \ 15,  , 7
 \                END-CODE       \       17 for 386

 CODE 2*    ( n -- 2*n ) \ suggested (and tested)) new coding
     MOV BX, SP                \  2,  , 2
     SHL 0 [BX], # 1 WORD      \ 26,  ,  7
     NEXT    END-CODE           \        9 for 386 - mps

     F-PC for the 386 will need a lot of codde changes if we're to 
 get all thhe speed of the new chip..  One change that I'd favor is 
 storing double numbers in memory and on the stack in the lo - hi 
 manner adopted  by Intel (consistent  with the way 16 bit words are 
 stored now).  I think you uncovered  a design flaw in forth! 

     With this change, pop ax and pop eax would both work without 
 bit twiddling.  This shouldn't affect most programs, those that use 
 doubles as units, e.g.., with 2@ and 2!, but might cause problems if 
 programs play "gaames" with the doubles.  The stack needn't be 
 changed; it would bbe a 16 bit and 32 bit stack simultaneously, as 
 it is now!  The program(er) would have to keep track of what's on 
 the sstack, but that's the way it is now, too.

     BTW, I downloaded obk3501 and it's impressiive.  Fine Job.
 Just a suggestion: fill in some code for PERFORM (does anyone
 use it?). ;-)

      - Mike -

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