On Mon, 9 Aug 2010 15:36:43 -0400, Abe Kornelis wrote: >On Mon, 9 Aug 2010 10:27:08 -0700, Edward Jaffe wrote: >>Sorry. Don't know the opcode for MVCX. But, since I knew it was already >>an assigned instruction mnemonic, I decided to use that name for a >>macro. If they ever externalize it I'll be "screwed". :-D > >Ok, I'll admit MVCX is entirely new to me. >Never ran into it until just now. >I can understand the opcode is unknown, >but would like to find out just what >we _do_ know about this instruction. >Is it real? What is it supposed to do?
There is a millicode-only instruction with a mnemonic of MVCX. It is used by millicode for variable-length moves without the need for EX+MVC. (The "Execute" instructions are really slow on modern machines.) MVCX is used by the millicode for MVCL and other instructions. We know of the MVCX mnemonic but not the op-code or the operand format.
