New answers tagged

4

Try reading as far as Pages 2 and 3 of your data sheet: Four general purpose registers, program counter, and three internal special-purpose registers. Calling something which "holds the data being transferred from the ALU to the destination accumulator register for one clock cycle" a "scratch register" might have been done by the marketing department who ...


5

Looking over the data sheet referenced, there is also an Instruction Register, and a "Bus Register". The IR is obvious. The BR seems to perform a similar function for fetched data (not instructions). Together with the 4 accumulators, PC, and SR makes 8 16-bit registers.


1

Pretty much any One Instruction Computer architecture could be described this way. In such machines, there is no opcode field, and the operation performed each time is sufficiently flexible to have several different effects depending on the operands given. If the operation implemented is Decrement And Conditionally Branch (which has been shown to be Turing ...


4

The Pilot ACE, commercialized as the English Electric DEUCE, had an instruction set which looks pretty peculiar to modern sensibilities. It had no explicit 'opcode' field, instead just source and destination addresses (as well as 'next instruction' address and timing-related fields). The address fields surely required some decoding, but then again it's ...


11

Horizontal Microcode works exactly as you describe - one bit for each possible internal control line (Vertical Microcode saves instruction bits by encoding sets of N mutually-exclusive control lines with log(N) bits, with appropriate demultiplexers in place). In theory one could use this as the primary instruction level, but of course it would be very ...


10

(Preface: The question is a bit misleading, as many of the conditions implied are not well defined. See below) First candidate: Transport Triggered Architectures Transport Triggered Architectures are not only a special case of single instruction architectures, but should this the 'no decoding' requirement quite nicely. Its only instruction is to transfer a ...


Top 50 recent answers are included