IMUL - Signed Multiply


	Usage:	IMUL	src
		IMUL	src,immed  (286+ only)
		IMUL	dest,src,immed8  (286+ only)
		IMUL	dest,src  (386+ only)
	Modifies flags: CF OF (AF,PF,SF,ZF undefined)


	Signed multiplication of accumulator by "src" with result placed
	in the accumulator.  If the source operand is a byte value, it
	is multiplied by AL and the result stored in AX.  If the source
	operand is a word value it is multiplied by AX and the result is
	stored in DX:AX.  Other variations of this instruction allow
	specification of source and destination registers as well as a
	third immediate factor.

				  Clocks		Size
	Operands	 808x	286   386   486		Bytes

	reg8		 80-98	 13   9-14  13-18	  2
	reg16		128-154	 21   9-22  13-26	  2
	reg32		   -	 -    9-38  12-42	  2
	mem8		 86-104	 16  12-17  13-18	 2-4
	mem16		134-160	 24  12-25  13-26	 2-4
	mem32		   -	 -   12-41  13-42	 2-4
	reg16,reg16	   -	 -    9-22  13-26	 3-5
	reg32,reg32	   -	 -    9-38  13-42	 3-5
	reg16,mem16	   -	 -   12-25  13-26	 3-5
	reg32,mem32	   -	 -   12-41  13-42	 3-5
	reg16,immed	   -	 21   9-22  13-26	  3
	reg32,immed	   -	 21   9-38  13-42	 3-6
	reg16,reg16,immed  -	 2    9-22  13-26 	 3-6
	reg32,reg32,immed  -	 21   9-38  13-42	 3-6
	reg16,mem16,immed  -	 24  12-25  13-26	 3-6
	reg32,mem32,immed  -	 24  12-41  13-42	 3-6


	- see Instruction Timing