From: joemonk64@gmail.com   
      
   > This is a feature of the assembler. The assembler on the   
   > mainframe recognizes the LGR and generates a different   
   > opcode, even though the registers are identically named.   
      
   LR is OPCODE 18. OPCODE 18 is ALWAYS a 32-bit operation.   
   LGR is OPCODE B904. OPCODE B904 is ALWAYS a 64-bit operation.   
      
   So just looking at the opcode I know what is going on...   
      
   By contrast, the MOV instruction is context sensitive. MOV EAX? 32 bit   
   operation. MOV AX? 16-bit operation. MOV AH? 8-bit operation. MOV is always   
   opcode B8. But just looking at the opcode do I know if I am moving 8 bits, 16   
   bits or 32 bits? No.   
      
   Thats why IBM object code is so much easier to work with than x86. And thats   
   why the two machines are worlds apart and dont operate in the same way.   
      
   Joe   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)