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(Only partial answer) Using a CMOS does not just happen because of the need of low power, but availability as well. Already in the late 80s, CMOS were sold at the same or even lower price as NMOS variants or being the the only offer some manufacturers had at all. Since the CMOS was in most parts compatible with the NMOS version, decision to use one was made ...


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There is the 6809 which has 2 Stack Pointers, SP and USP (user stack pointer). I think the 68K can manipulate the pointers such that the Stack address can be exchanged with it's other registers.


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Sure this is about Motorola? Could it be have been about a similar sounding manufacturer, like Mostek? Because the first to come to mind would be Zilogs Z80, which was first manufactured by Mostek, as Zilog had no production line of its own. The description about being dedicated to fast interrupt handling is also exactly what the Z80 implementation was ...


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Making your own Z80 computer is the subject of several books written in the 80s, such as Byte Books' Build Your Own Z80 Computer: Design Guidelines and Application Notes by Steve Ciarcia, which is freely available online and Beginners Guide to Computers & Microprocessors with projects by Adams. You've correctly anticipated that the computers that these ...


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Are you interested in running any particular kind of older software, once you've gotten it working? That should dictate what kind of CPU you use. For example, if running WordStar or Zork is paramount you'd want to use a Z80. All the processors have their special fun features. Don't discount the 6809, either. To answer the question, yes it is possible. ...


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The PDP-10 calling sequence should be contrasted with the VAX calling sequence to get a good handle on two very different approaches. The PDP-10 requires the program to issue an extra code, while the VAX does not. This reflect changes in system designs between about 1965 and 1975. The PDP-10 used unused opcodes (UUOs) to request services from the ...


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I would guess that the biggest argument against such opcodes is that there are generally better uses to which the opcodes could be put. The 68000 reserved a range of opcode bytes from 0xA000-0xAFFF for the purpose, which the original Macintosh OS used extensively, but a single-word A-line-trap instruction wouldn't really offer much advantage over a two-word ...


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Two issues... the wobble was because the post-transform 2D vertex coordinates for each triangle were integers... So the vertex could only move on discreet pixel locations. This makes smooth vertex movement virtually impossible. PS2 for instance fixed this by having fixed point fractional screen vertex locations, helping smooth movement out. Other later ...


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Note: I'll ignore the payphone aspect of your question for the moment: I'll just treat it as wanting to connect together a number of old, pulse-dial telephones for internal communication. Pulse-Dial PBX Essentially what you need is a small PBX (Private Branch Exchange). These come in all sizes from around four-lines up to several thousand and are used in ...


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The question seams to be based on the assumption that the Atari 800 slots are somehow not 'real' slots. Similar it implies that the mentioned "70's FCC regulations" were some kind of incredible strict. But the Atari slots do carry everything needed for expansion. And making a system to fit FCC Part 15 regulation wasn't some dark art, but could be rather ...


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The Nintendo 64 not only has full-perspective texturing, it can afford bilinear filtering — for each output pixel the PS1 samples the input texture exactly once. The N64 samples it four times and linearly interpolates according to how close it is to each (in two dimensions, hence bilinear). The Saturn has a couple of tricks up its sleeve: the primitive is ...


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For the PlayStation 1, development was done on a development kit which fit inside a PC; this included two ISA cards, and had 8 MiB of RAM for the PlayStation CPU. Pre-production testing was done on debugging consoles, which were closer to the production hardware, and only had 2 MiB of RAM. SN Systems (which designed the development kit) also produced a ...


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I wonder if it might also have been the influence of tradition/habit. Things like pinball and pachinko have to be vertically oriented because the ball is pulled towards interaction with playing field elements (the bumpers, gates, etc.) by gravity, so the elements have to be stacked vertically. A landscape pinball machine would make for short turns and ...


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The hardware reset isn't an optional feature for a reset switch - it's an essential function for starting the CPU up correctly. As the power supply rail rises, circuitry within the CPU, such as the register set, will take on random-ish values. The clock oscillator will unsteadily start working and CPU would start trying to operate before the supply was at a ...


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The 6502 data sheet (archived at http://archive.6502.org/) on page 2 gives the requirements for the RESET line as: After Vcc reaches 4.75 volts in a power up routine, reset must be held low for at least two clock cycles. At this time the R/W and SYNC signals become valid. As I recall from using the chip, a poorly designed POR (power on reset) circuit ...


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Yes, you're correct. The original 6500 family does not include a Power-On-Reset (POR) circuitry. For reliable startup reset has to be pulled after power up. To avoid unintended execution of random code, it's recommended to keep Reset pulled by default and only release it after power is stabilized. Then again, depending on your setup it may be acceptable ...


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My family owned an arcade parlor of sorts in the mid-1970's when Space Invaders, Pong, and PacMan were replacing mechanical games. I have seen the insides of many old-school arcade games when they were relatively new. In the early games the CRT was often mounted horizontally. What you saw was a mirror at about 45 degrees that reflected the CRT and made it ...


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Less historical example: ARM (Advanced RISC Machines...) Cortex-M4 has many (though a clear minority) instructions that execute in more than one cycle. See this list: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0439b/CHDDIGAC.html Cycle count gets less clear when pipelining or dual-issue is introduced (like in the Cortex-M7)


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Note that paper is usually also vertical, as were many early desktop PCs. Where does horizontal come from? Many professionals used vertical screens on PCs (and some still do) whenever possible. It's great for reading, which is why this very site only uses a fraction of the display to show actual content - the thing you're supposed to read still fits a ...


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I'm sure there were plenty of early "RISC" engines which took on the order of 8 cycles per instruction. One cycle to fetch the instruction, one to access the registers, one to store the result, one to increment the instruction counter. That's 4, but the fetch may have taken several. (In case anyone's wondering, I was in meetings with George Radin ca 1975.)...


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To start with, cycles, especially cycles in term of some external clock source aren't really a good measurement at all. Already with the mentioned 6502 internal workings are tied to two clocks effectively doubling the clock rate the chip works at (PHI0->PHI1/2). Something easy to see with the Visual 6502 simulator. Next, as Martin Rosenau has shown, even ...


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Classic RISC CPUs like ARM ... instructions execute in one cycle ... This assumption is not correct. The ARM-2 CPU (VL86C010, one of the first ARM CPUs) took: Only one cycle for most operations (as you expected it) Typically two cycles if a jump/branch was done Up to 4 cycles for shift/rotate operations Up to 16 cycles for multiply operations Up to 17 (or ...


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One RISC CPU I know of is included in the PIC microcontrollers: I happen to have an old General Intruments data book that says the oscillator clock is divided by sixteen for some part, and by four for some other part. The well-known 8-bit PICs by Microchip divide their system clock by four into instruction cycles. However, there were clones that run at ...


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Having the display vertical reduces the width of the cabinet. This means that a game machine can be fitted into a smaller space in a pub/bar, or in an amusement arcade where machines are in rows you can get more machines (potentially a third more) into the same space. One-third more machines means one-third more revenue. The orientation may also have been ...


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(From the perspective of the electronics, that means the displays were drawn sideways.) Not necessary. There is no inherent reason for drawing sideways. A video circuit can easy be made for either, as line width and number of lines can be defined either way. This is especially true for early games, where electronics were rather special to type and so was ...


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This answer isn't backed up by facts or testimonies. It only reflects my personal thoughts The main reason is probably that early games such as Space Invaders (and Galaxian, Galaga...) or Breakout have a gameplay where vertical resolution / room is more important. Objects (bullets, balls) are travelling vertically. And the rest of games that could have ...


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To start with, the citation is a bit misleading. The logic didn't handle 128 sprites and 256 tiles at a time, but its ROM could hold as many different ones. The arcade board does not feature a free programmable sprite engine. There is a fixed sets (128) of direct addressable graphics in 8 KiB of ROM used (128 x 32 x 16). A set of shift registers, feed by ...


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