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All the parts of the CPU are executing instructions at some point of time or the other. The part(s) that is/are executing an instruction at a given time depends on the instruction being executed. For example, in an add instruction, the ALU performs addition in the execute stage of the instruction cycle. Through a process called pipelining, more than one ...


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If you want to implement a multiplier in a lookup table in memory of any sort, then for 4x4, you'd need address space that covers the width of both source operands. In this case, you'd 8 bits. That is 256 addresses, and room for every combination. When you multiply, you double the bits needed of each operand in the result. The type of memory you use doesn't ...


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Actually, instructions don't all take the same time in RISC. They are forced to all take a fixed number of cycles, but the latencies will vary, and even within the same instruction. For instance, adding 1 to 0x01111111 is harder than adding 1 to any even number. And you can do RISC or CISC regardless of the strategy used to obtain such an architecture. It ...


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"Bus speed" isn't the right technical term, since it is ambiguous. The speed of electric signal depends on the speed of the electromagnetic wave in that medium, and is not necessarily equal to the speed of light in vacuum. The maximum information data rate, reported in Bits/Second, is the rate at which data can be transferred without loss of ...


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Not much. Bits 2 and 5 will get swapped over when the CPU reads memory but also when it writes memory, so it cancels out. It will only make a difference if some other hardware device is also accessing the RAM and not swapping over those bits.


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Note that Turing machines don't have any function calls, and they work just fine as Turing machines. Function calls are not a necessity for Turing-completeness. All non-recursive function calls can simply be inlined. Recursive functions can be translated to loops using an explicit stack, the same way the CPU actually executes them (see below). A typical 32-...


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Is there a return address stack on the CPU (limited to memory on chip), or is it emulated in software at the assembler using regular RAM? Yes. Some processors do not have a stack (and need to emulate it using RAM for everything) Some have a fixed size stack Most use general purpose ram via a stack register Some have a stack that is partially in CPU cache ...


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