From: luser.droog@nospicedham.gmail.com   
      
   On Monday, September 14, 2020 at 3:51:24 AM UTC-5, Alexei A. Frounze wrote:   
   > On Sunday, September 13, 2020 at 11:51:13 PM UTC-7, luserdroog wrote:   
   > >     // additional flags set by math operators   
   > > #define MATHFLAGS *fl |= ( (z&(w?0xffff0000:0xff00))     ?CF:0) \   
   > >                        | ( ((z^x)&(z^y)&(w?0x8000:0x80)) ?OF:0) \   
   > >                        | ( ((x^y^z)&0x10)                ?AF:0); \   
   > >                        SETPF   
   > >   
   > > I don't know where I came up with that expression for OF.   
   > > It's gibberish to me now.   
   >   
   > It's making sure that the result's sign is the same   
   > as the signs of x and y. If that isn't true, OF gets set.   
   > That works for addition, z = x + y,   
   > but not subtraction, z = x - y.   
   > Unless you exchange things a bit...   
   >   
   > add: z = x + y   
   > (z^x)&(z^y)&...   
   >   
   > sub: z = x - y   
   > OR, speaking in terms of addition...   
   > sub: x = z + y   
   > (x^z)&(x^y)&...   
   >   
   > IOW, for the purposes of OF calculation you need to   
   > exchange x and z in that formula of yours.   
   >   
   > Alex   
      
   Do I also need to swap x and y if the direction is   
   reversed and z = y - x?   
   then y = z + x.   
   sthg like:   
     ((d?x:y)^z)&(x^y)&...   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)