XPost: alt.lang.asm, comp.os.msdos.programmer   
   From: admin@nospicedham.127.0.0.1   
      
   On Sun, 26 Feb 2023 20:33:41 +0100   
   Terje Mathisen  wrote:   
      
   > Kerr-Mudd, John wrote:   
   > > On Mon, 13 Feb 2023 22:31:01 +0000   
   > > "Kerr-Mudd, John"  wrote:   
   > >   
   > >> Many years (decades actually) ago a one time regular here, Laura   
   > >> Fairhead, posted a com to ascii program, called CM3. I've gone back to   
   > >> looking at the decoder and have failed to find any way of shortening   
   > >> it. But I've revamped the "create" program to just output ASCII code   
   > >> (dropping the batch surrounds of 'Echo/' and '>>fn.com') from 759   
   > >> bytes to 394 and made another that outputs the encoded program to STDOUT   
   > >> (rather than immediately executing), that one's a bit shorter at 376.   
   > >> As they are just variations on a theme, the same restriction applies:   
   > >> max com file input size is c.50k. (one read, one write)   
   >   
   > I love this stuff!   
   >   
   Hope you found it works OK your end.   
      
   > Now go back and redo this using only those ascii chars that are   
   > guaranteed (by the MIME standard) to never needing to be quoted, i.e.   
   > they will pass transparently over every single known email gateway etc.   
   >   
   > You end up with 70+ valid byte values, the worst problem is how do you   
      
   Laura used 5:4 encoding which requires 85 ASCII codes.   
      
   > address ememory when all opcodes that target (POP) BX/SI/DI/BP happens   
   > to use banned byte values. The only way I found to make it work was to   
   > require at least an 80186 which is the first cpu to support POPA. :-)   
      
   Well quite; I think that's the only way. So I'd say it can't be done. I   
   refuse your challenge!   
      
   >   
   []   
   > >>   
   > >> 1) Program to convert a DOS COM file to ASCII executable;   
   > >>   
   []   
   > >>   
   > >> 2) Program to create an ASCII text program which can then be   
   > >> run to recreate a DOS binary program.   
   > >>   
   []   
   3)   
   > > I have since created a hex executer in a similar vein   
   (Doesn't work under XP, but works with std dos .COM startup values)   
      
      
   --   
   Bah, and indeed Humbug.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)