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   alt.os.development      Operating system development chatter      4,255 messages   

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   Message 2,633 of 4,255   
   mutazilah@gmail.com to Joe Monk   
   Re: PDOS/86   
   15 Jul 21 18:48:27   
   
   From: muta...@gmail.com   
      
   On Friday, July 16, 2021 at 10:56:55 AM UTC+10, Joe Monk wrote:   
      
   > > The same way that z/Arch running in AM64 executes   
   > > a LR R3,R4 perfectly fine.   
   > >   
   > > So too the 80386 will execute "mov ax, bx" perfectly fine,   
   > > in exactly the same manner as the 8086.   
   > >   
   > > At least I think it will. I'm more familiar with S/3X0   
   > > assembler than x86.   
      
   > On an S/370, an LR R3,R4 is a 32-bit move. Same for S/390, and z/Arch.   
   >   
   > On an 8086, a mov ax,bx is a 16-bit instruction. Same on the 80386. In PM32,   
   that register is called EAX. AX only references the lower 16 bits of EAX.   
   >   
   > See the problem? They're not the same operations.   
      
   In the same way that z/Arch supports both 32-bit and 64-bit operations,   
   the 80386 supports both 16-bit and 32-bit operations.   
      
   You can do a mov ax, bx on both the 8086 and the   
   80386 (even in normal PM32, forget RM16, forget   
   V8086).   
      
   Or am I missing something?   
      
   BFN. Paul.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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