If you could assign function to the *reserved A5 instruction in the 8051, what would it be? My vote: Choice 1, movx dptr,@dptr+a Choise 2, dec dptr *From what I recall, this instruction is reserved for the interrupt mechanism, which (upon an interrupt) crams this instruction into the decoder as a special jump-to-vector command. Thus, its likely we'll never see any variant actually using the A5 instruction, but its fun to wish just the same.
Working from memory, I think that the op-code is reserved by Intel and has been used in the 251 to switch between the backward compatible 80C51 instruction set and the new super dooper but longer 251 instructions.
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