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From: ForthNet@willett.UUCP (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: forth eng./68hc11 new micros
Message-ID: <601.UUL1.3#5129@willett.UUCP>
Date: 2 Mar 90 03:56:47 GMT
Organization: Latest link in the ForthNet chain.  (Pgh, PA)
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 Date: 03-01-90 (00:53)              Number: 406 (Echo)
   To: ALL                           Refer#: NONE
 From: JACK BROWN                      Read: (N/A)
 Subj: FORTH SOLUTION TO 1E          Status: PUBLIC MESSAGE

 ( 68hc11 Assembly Language Programming Course                     )

 ( Problem 1e )
 ( Write a 68HC11 assembly language program which will do this:    )
 ( If bit 5 of ;memory location $0020 is set, 1, then clear memory )
 ( location $0010.  If bit 5 is clear then set it.  Note: do not   )
 ( disturb the state of any of the other bits in the byte.         )

 ( Solution 1e )
 ( We use memory locations $00A0 and $0090 instead of $20 and $10  )
 HEX
 00A0 CONSTANT BFLAGS
 0090 CONSTANT DATA

 ( Check bit 5 and take appropriate action.  This is a bitch for   )
 ( the Forth assembler as we need to fake a forward reference and  )
 ( make sure that it is properly resolved.                         )
 CODE BITCH  ( -- )
                   HERE        ( dummy address for BRCLR, )
  BFLAGS  0020     BRCLR,      ( branch if bit 5 clear    )
 ( IF, )  HERE 1-              ( back address for ELSE,   )
          DATA     CLR,
 ELSE,
  BFLAGS  0020     BSET,
 THEN,
                   NEXT
 END-CODE

 NET/Mail : British Columbia Forth Board - Burnaby BC - (604)434-5886   
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