Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!orion.oac.uci.edu!ucivax!jarthur!bgribble From: bgribble@jarthur.Claremont.EDU (Bill Gribble) Newsgroups: comp.sys.handhelds Subject: Re: Display question Message-ID: <10607@jarthur.Claremont.EDU> Date: 1 Feb 91 19:05:34 GMT References: Organization: Harvey Mudd College, Claremont, CA 91711 Lines: 38 In article TNAN0@CCVAX.IASTATE.EDU writes: >The HP-48sx display is memory mapped, but it is NOT fixed. The various >parts of the display (stack area and menu label area) can be moved >independantly of each other (by poking around near address 100h - I >believe that it's 120h-124h actually for the upper portion of the screen >and 130h-134h for the lower). Anyway, my question is: Where does the >HP keep track of the current addresses associated with the position of the >screen (120h-124h and 130h-134h provide no useful information, they are >write-only). From a list of useful RAM addresses: loc_menugrob=#70551 loc_stackgrob=#70556 these locations contain pointers to the grobs you're talking about. So the code bit move.p5 loc_stackgrob,a move.a a,d0 move.a @d0,a swap.a a,d0 add.a #a,d0 add.a #a,d0 will leave d0 pointing to the start of stack grob data. You can't change the pointers, but you can follow them and modify the existing grobs with impunity. (You're betatesting NRTS, aren't you? Then you've seen this in action!) >---Xeno ***************************************************************************** ** Bill Gribble Harvey Mudd College, Claremont, CA ** ** bgribble@jarthur.claremont.edu Never heard of it? You're stupid. ** *****************************************************************************