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| ASM programming is FASCINATING! |
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| T3sl4co1l:
Something of an aside, but related: an IO bus is just another set of bus strobe signals. So the x80/x86 family has theirs. 68x doesn't (all memory mapped, AFAIK?). Others have banked memory (and you could put IO into that just as well). Or you could reserve entire segments of address space for various purposes. A more general interpretation, then, could be considering any of the signals as bus enables. The CPU asserts some combination of them; and this is now in binary rather than unary coding. That is, the traditional multiplexed memory/IO space uses single strobes to select between them; say we have N address spaces: for N > 3, it's more efficient to use lg(N) address lines and a single strobe (and a lg(N)-->N decoder at the destinations) to do the same thing. So we might consider an arbitrary number of common-bus address lines as bus-select lines for our various buses. A banked memory system extends this further by using a sequence of operations with a stateful bus to make the selection. These are already familiar to many IO devices, where for example one register's value serves as the address to the second register. Tim |
| westfw:
--- Quote ---Ironically, x86 has a Harvard architecture IO bus --- End quote --- Harvard is usually about Instructions vs Data. I don't think IO Buses count... |
| KL27x:
If I ever find myself disagreeing with Tim, my default conclusion is I don't know enough to understand how he is right. >:D |
| SiliconWizard:
The Wikipedia article more or less details what I summed up above : https://en.wikipedia.org/wiki/Harvard_architecture These days, most CPUs are actually some form of "modified Harvard" rather than pure Von Neumann architectures. Not that it matters much, since the original definitions applied to very simple architectures - most modern CPU architectures are much more complex in comparison. |
| eti:
--- Quote from: ebastler on July 30, 2020, 06:57:24 pm --- --- Quote from: Nusa on July 30, 2020, 09:26:54 am ---To the OP that's just having fun learning, I recommend the following book: --- End quote --- We seem to have lost the OP a while ago. More specifically, we lost him right after his original post. Maybe the fascination didn't last. ::) --- End quote --- No no, I am still browsing, I just have a real life outside forums, you know? There's only 24 hours a day, and I can't spend all of them online :) Besides, I bow to the superior ASM knowledge of all thread contributors; suffice to say that you guys appear to have infinitely more experience than me in this area, which is new to me for now, and I enjoy reading as and when I get 5 mins off to come here. |
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