From: muta...@gmail.com   
      
   On Tuesday, July 13, 2021 at 1:05:23 PM UTC+10, wolfgang kern wrote:   
      
   > >> so why don't you stick to 386 and forget no more existing   
   > >> old crap ?   
      
   > > I would like to have a solution to the 80286 too.   
      
   > you wont find a working 286 anymore, not even in the museum.   
      
   On a phone call at work about 2 weeks ago, someone   
   was bragging that they had an AT.   
      
   On discord about 3 weeks ago, someone said they had   
   brushed off an old XT and wanted to do OS programming   
   on it and thus wanted a 16-bit compiler, at least ideally.   
      
   > and return from PM needs hardware to react on forced crash.   
      
   Ok.   
      
   > >>> And if I can get the 8086 to trap and ignore db'66' and   
   > >>> db'67' I will be able to have 16-bit executables that work   
   > >>> on either shift value.   
   >   
   > >> Now that's a really bad idea. compiled code may look like:   
   > >> 66 b8 44 33 22 11 MOV eax,imm32   
   >   
   > > No, I won't use 32-bit instructions.   
      
   > with the prefix it is still a valid (386) 16 bit instruction!   
      
   Ok, I'm after instructions that work on both an 80386 in   
   protected mode (adding a x'66' is fine) and an 8086   
   (with or without the ignored x'66').   
      
   Basically the intention is to get the C compiler to generate   
   16-bit instructions that work in either environment, adding   
   an x'66' when it knows it needs to.   
      
   Is there enough instructions that will work this way?   
      
   > and many applications may use overrides, BIOS also do it.   
      
   Ok, the BIOS can be dedicated 80386 or dedicated 8086,   
   I don't care about that.   
      
   For now I only care about applications.   
      
   > > If I just have bb 44 33, will it work on both the 8086   
   > > and the 80386?   
      
   > Yes as long 386 is in RM or PM16,   
      
   No, I don't want that. I want PM32.   
      
   > but it become a five byte   
   > opcode in PM32:   
   > bb 44 33 22 11 MOV ebx.imm32   
   > or a four byte:   
   > 66 bb 44 33 MOV bx.imm16   
      
   This 4 byte one looks like it will work on both PM32   
   and RM16.   
      
   That's exactly what I'm after.   
      
   It will all work, right?   
      
   Thanks. Paul.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)