Chapter 16AppendixExtension Instruction Specification XVI - 733) Precautions for describing word/halfword data multiply and accumulate instruction and MCRH andMCRL access instructionWhen a word/halfword data multiply and accumulate instruction and MCRH and MCRL accessinstruction are executed, the result of the word/halfword data multiply and accumulate instruction is usedto execute the MCRH and MCRL access instruction. For this reason, the next MCRH and MCRL accessinstruction must be activated after the result of the word/halfword data multiply and accumulateinstruction, that is required for the MCRH and MCRL access instruction, has been output. Therefore, it isnecessary to provide 3 cycles between the preceding word/halfword data multiply and accumulateinstruction and the succeeding MCRH and MCRL access instruction.Figure:16.4.5 Drawing of Pipelining for Precaution (3)This precaution is applicable to the following instructions:MAC, MACI, MACH, MACIH, MACU, MACIU, MACHU and MACIHU instructionsPUTCX, CLRMAC, GETCHX and GETCLX instructionsDECWord/halfword datamultiply and accumulateinstructionInsert 3 cycles Result availablefor referenceMCRH and MCRL access instructionInstructiondecodingInstructiondecodingOperation OperationMultiply and accumulateinstruction outputs the resultrequired for MCRH and MCRLaccess instructionEXMEMWB
