Chapter 16AppendixExtension Instruction Specification XVI - 755) Precautions for describing byte data multiply and accumulate instruction and MCRH and MCRL accessinstructionWhen a byte data multiply and accumulate instruction and MCRH and MCRL access instruction areexecuted, the result of the byte data multiply and accumulate instruction is used to execute the MCRHand MCRL access instruction. For this reason, the next MCRH and MCRL access instruction must beactivated after the result of the byte data multiply and accumulate instruction, that is required for theMCRH and MCRL access instruction, has been output. Therefore, it is necessary to provide 2 cyclesbetween the preceding byte data multiply and accumulate instruction and the succeeding MCRH andMCRL access instruction.Figure:16.4.7 Drawing of Pipelining for Precaution (5)This precaution is applicable to the following instructions:MACB, MACIB, MACBU and MACIBU instructionsPUTCX, CLRMAC, GETCHX and GETCLX instructionsDECByte data multiply andaccumulate instructionInsert 2 cycles Result availablefor referenceMCRH and MCRL access instructionInstructiondecoding InstructiondecodingOperation OperationMultiply and accumulateinstruction outputs the resultrequired for MCRH and MCRLaccess instructionEXMEMWB
