| 摘要 |
PURPOSE:To obtain a constant having a large range of expression with a single microinstruction by delivering the contents of the 2nd field of a holding means to only one of plural data generating means and connecting the outputs of other data generating means to use them as the constant data. CONSTITUTION:The selection signals SELO, 1, 2 and 3 are active when the byte position information BYTO/1 is equal to '00', '01', '10' and 11 respectively. The lower 8 bits of an instruction field and outputted to the outputs of the 8-bit data generating means 110-113 selected by signals SELO-3. However the zero data of 8 bits are outputted to the outputs of three sets of means 110-113 which are not selected since a 2-bit decoder 115 produces those signals SELO-3 so that they are exclusively active. Thus it is possible to obtain a 32-bit constant that sets the 8-bit data at an optional byte position.
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