Posted by Computer Consultant on 1998-03-14
Dear Mr. E, The DB 66h is a type cast. Exame this example: MOV AX, 4 That assembles into B80400 in REAL MODE. In Protected Mode, It assembles into 66B80400 MOV EAX, 4 in REAL MODE assembles into 66B804000000 But, In Protected Mode it assembles into B804000000 Depending on what mode of the CPU you are programming in will decide what gets typecasted. In REAL MODE, 32-bit instructions are type casted. In Protected Mode, 16-Bit Instructions are type casted. A Type casted instruction is slower than an instruction that is not typecasted. Scrat/_Secret http://www.nauticom.net/www/secret > Date: Fri, 13 Mar 1998 10:22:02 GMT > From: John Stokes <hc97js@xxx.xx.xx> > Subject: "Send PCG key" > Mr E here, > I am currently decoding a sprite routine that uses rep movsw for > putting the sprite data on the screen. > I am stuck with the operation of DB $66. Could anybody please tell > me what this does? I think it is something to do with double words as opposed > to words, if that helps! > THANX. John.
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