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   comp.sys.raspberry-pi      Raspberry Pi computers & related hardwar      26,127 messages   

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   Message 25,181 of 26,127   
   mm0fmf to All   
   OT: horrible 8086 segmentation   
   25 Nov 24 17:33:37   
   
   From: none@invalid.com   
      
   Raspberry Pi relevance : I'm writing some Pi Pico code   
      
      
   I was doing some head scratching when I remembered I'd written something   
   very similar in the distant past to what I was doing. I had to dig   
   through piles of CD-Rs to find the one with the backups on from all   
   those years back. It still reads fine, 21st July 1998 is the date on the   
   CD. 26 years old.   
      
   Anyway, I've pulled the files from it on to the wee Linux machine for   
   updating and use in the project. There's a date in the header saying   
   "created 1993" and last changes were "16th July 1996". I was just   
   starting to go bald then!   
      
   I've been rummaging through this old CD-R looking at what I was up to   
   all those years ago and found all sorts of horrible 8086 segmentation   
   management in the C code   
      
   e.g.   
   "   
        // start of barrel   
        EventRec far* searchp = (EventRec far*) work.bufs;   
      
   "   
      
      
   My eyes! My eyes! That was COMPACT model code, so 64k of code and 1MB of   
   data, code addresses were 16bit offsets to the CS reg and data was far   
   so 32 bits of segment and offset of DS or ES. And of course you had to   
   be extra careful of any pointer arithmetic as a far pointer wrapped   
   after 64k. You had to use slower HUGE pointers to get automatic   
   normalisation. God it was shit.   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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