section 7 - Index of

X:R X Memory and Register Data Move X:RIf the opcode-operand portion of the instruction specifies a given source or destinationregister, that same register or portion of that register may be used as a source 81 and/or82 in the parallel data bus move operation. This allows data to be moved in the sameinstruction in which it is being used as a source operand by a data ALU operation. Thatis, duplicate sources are allowed within the same instruction. Note that 81 and 82may specify the same register.Class I Example:CMPM VO,A A,X:$1234 A,VO;compare A,VO mag., save A, update VOBefore ExecutionA 1~ _____ $0_0:_80_00_0_0:0_0_00_00 __ ~After ExecutionA 1~ _____ $0_0_:80_0_00_0:_00_00_0_0~X:$1234I$000000 X:$12341~ __________ $7_FF_F_FF __.......J~--------------~yol~ ________ $_O_OO_OO_O __ ~YOI~ ________ $_7F_F_FF_F __.......JExplanation of the Class I Example: Prior to execution, the 56-bit A accumulator containsthe value $00:800000:000000, the 24-bit X memory location X:$1234 contains thevalue $000000, and the 24-bit VO register contains the value $000000. The execution ofthe parallel move portion of the instruction, A,X:$1234 A,VO, moves the 24-bit limitedpositive saturation constant $7FFFFF into both the X:$1234 memory location and the VOregister since the signed portion of the A accumulator was in use.-