PC still playing Amiga catchup

[amigaksi]

Are you sure?

Yep, just read the HPET spec which deviates by 2 clocks + or - from where actual tick count finishes.  Just run some copper color change in the middle of the screen (horizontally and vertically) and reply back when it changes position.

[amigaksi]

It certainly is. The point is: who cares ?

If this was a real problem I'm sure someone would have adressed this issue on PC hardware. But it seems everyone is living with it. Not to mention no one ever used it or mentionned it on the Amiga either.

So what's the point ?

People participating in this topic should care.

Because PCs were originally business machines so they failed to address or did not both addressing issues related to gaming (which relates to multimedia as well)-- sprites, multiple audio channels, joystick types (digital vs. analog), joystick ports, timing, etc.  These things were not needed to do word processing, communications, running excel, or doing mathematical computations.  Gradually, they started addressing these things-- adding in audio cards, faster local bus graphics cards, better ways to time video-related stuff, etc.

So the points so far are as stated in msg #275.

[amigaksi]

Even if that was right, you still honestly believe that sampling the transition stages from e.g. left to right would have any impact on gameplay? Which planet are you from? What matters to the application is the intended directional input from the player, which renders the transition stages to be A: inaccurate and B: useless.

You are still speculating.  First of all, those transitional stages aren't just going left to right and even that is accurate and useful.  Even if you sample at lower rate, you may get that transitional state in your sample.  Secondly, the fire button(s) are indepependent of the joystick directions so you can get minute values for timing of the states.  It's not a matter of opinion whether you THINK it has impact on gameplay.  It's more accurate to take into account all the various states of the joystick just like it's more accurate to sample sound at 44Khz although it may make little difference to many people if they sampled at 32Khz.  Or another example was the MP3 which distorts some samples compared to lossless audio.

As far as which planet I am from.  Well, that's a tough one-- if I take into account reincarnation, it could be many.

[amigaksi]

The 1 second periodicity was only an example. You could trigger it every 10 seconds. What matters is whether the game responds to the 1ms wide pulse whenever it is issued. If it doesn't then the game simply isn't sampling at a rate that guarantees a sample is read within a 1ms window - ie it isn't sampling at 1kHz. By gradually increasing your pulse width to the point where you get a consistent response (eg 9 in 10 pulses trigger the action) then you know you are in the right approximate resolution of the application's sample rate.
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I do have some source code for games that just poll the joystick without waiting for VBI.  In the case of River-raid, it does not let you fire again until the missile hits its target or is off the screen.

>As for the rest, they could but that still does not demonstrate that any particular game title samples this quickly. You need to actually test with real applications that were written, not software you write purely to demonstrate that it is possible.

They are both useful.  See if they exist in existing applications and to show that it's more accurate to sample at higher rates.

>PS, see my other crazy idea to allow 1kHz sampling an analogue joystick. In case you can't find it, a quick recap:

>Use the X/Y potentiometers to adjust the left/right volume of a simple hardware oscillator running at several kHz that is sampled by the soundcard at 44.1 kHz. Calculate the RMS power for frames of 441 samples (one frame for left and one frame for right) and look up the RMS value in a suitable calibration table to determine X and Y position.

Computing an on-going RMS may slow things down though.  How about, just looking for a max/min value every millisecond or so and using up 4 channels to get a digital joystick out of it.

[amigaksi]

You can claim it all you like, but that doesn't make it true. It's approximately 558ns. An accurate figure, determined by a high precision scope might record 555, 559. I totally agree with you that it doesn't matter in system since the circuitry will all be running at whatever speed the clock gives, but the claim it is accurate to 558ns is not true at all. You have to quote a margin of error for any real measurement.

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There's some ppm rating on the crystals but in the general case it's more accurate than even the rating.  I know the NTSC/PAL crystals are pretty solid when it comes to timing since they have an exact formula to work with: 227.5*262.5*60/1.001 = NTSC color burst signal (3579545.4545Hz) and timing based on that should give 558.73ns for Copper.  Are you claiming that TV's are skipping frames once in a while?

>For example, some years ago, Redrumloa was experimenting with underclocking the main oscillator on the motherboard as he observied it was giving a speed up as based on common amiga benchmarking programs where the native chipset wasn't being used for video etc.

There are cases where there's manufacturer defect.  They do use the T=1/f even on PCs when they use the timer to update system time every 55ms or so.

[amigaksi]

Originally, they weren't. The first IBM PC shipped with 16KB RAM, a cassette tape interface, and BASIC in ROM. They accidentally failed in the home computer market, and succeeded in the business microcomputer market. They then tried again for the home market, with the PC jr. but failed. The PC jr. didn't really sell until they introduced a proper keyboard and an upgrade module that enabled it to be used for the same stuff that PCs were being used for.

Yeah, PC jr failed but IBM PC didn't have the colors, sprites, blitter, sound DACs, etc. and it's price was way too expensive for gaming or for home use.

[amigaksi]

Then they tried again with the PC/AT and blew everything away. Welcome to 2009

FYI, PC/AT was at 6/8Mhz.

[amigaksi]

...and the AT was released the year before the Amiga came out, what's your point?

Go ask the guy who stated that PC/AT blew everything away.

[amigaksi]

20 Years from now, when terabytes of non volatile memory are standard and video displays beam 3d images directly into your eyeballs, we're still gonna be arguing about joystick ports and boot up times.

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People decided to argue about these two points because they are capable of arguing them.  They didn't bother arguing about the other points stated.

[amigaksi]

I prefer my Xbox 360 controller (for Windows) over standard classic Amiga digital joysticks i.e. four standard analogue controls (e.g. LT, LT, RS, LS) and vibration feedback.

Someone just gave me an XBOX for $4.  I guess it's not 360, but probably same controllers.  Controllers are fancy looking, but they are still analog and confusing due to so many buttons.  Perhaps, they were trying to replace the keyboard with the joystick.  Tried a few games and still ended up doing eenie, meenie, minie moe...I guess they forgot to put in a help button.

Vibration feedback-- is that the propellors that come out of the joystick when player does something wrong and attack the user like Maximillian in the movie Black Hole?

Given all those buttons and killer propellers, I revised my poem regarding which button to press:

Eenie meenie minie moe
pick a button to shoot the foe
if it's wrong then let it go
next time it occurs you better know

[amigaksi]

Software abstraction layer enables the PC to adapt and not being stuck with a boat anchor.
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As I said, you can have both APIs and hardware level compatibility.  For PCs, that's a big problem nowadays.

>Most console-to-PC game ports(e.g. Games For Windows) includes support for the Xbox 360 controller.
 
Which port are you referring to as the "console-to-PC" game port?

>I recall Street Fighter II Amiga port didn't capture the arcade feeling i.e. the 1 button joystick standard is one of these issues.

Majority of games don't require the analogicity (can be done with digital joysticks) and don't require 10+ buttons.  They just have to be programmed to use one or two buttons.  Amiga joystick port can handle up to 3 buttons if you use the POTs as buttons as well, but it's easier to use a game with lesser buttons.

>IF there's a direct hardware access, what happens to the security objects?

First you need the hardware compatibility so you have a choice for hardware access.  Then there's obviously the IOPM in intel's processors to implement protection for ports for security purposes.

[amigaksi]

actually that is not an issue. if you allow direct hardware access then when the hardware changes you have to emulate the old chips. after a few generations that will be unwieldy as heck. this is why commodore was moving away from this idea of direct access before they died. they were trying to force everyone to create os friendly games and apps. this is so they could phase out hardware compatibility for older software. that was the first phase to allow retargetable graphics and sound.

Hardware is not supposed to suddenly change-- it's suppose to retain backward compatibility like for example 8253 is still in modern PCs although they added other means for timing things.  It's more efficient to do ASM instructions that directly read/write I/O ports than go through API calls.

[amigaksi]

In Windows NT, there are only two I/O privilege levels used i.e. level 0 & level 3. Usermode programs runs in privilege level 3. All usermode programs should talk to a device driver that arbitrates access i.e. to minimise conflicts.

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Yeah, that's the rule.  But if the at ring0 you had standardized hardware, you can write more efficient code.

>Define this "big problem nowadays." in terms of numbers.  One could write a kernel mode driver for I/O level 0 access. Most PC games talks to DirectInput or xInput APIs i.e. userland programmers do not have worry about specific implementations i.e. makes development easier.  

If those implementations were standardized like 8253 example I gave or even VGA standard modes, you can have more efficient code.  On Amiga, writing to OCS registers works for all OCS/ECS/AGA amigas.

>...IF you notice with PC GPU(a type of stream co-processor array) market, they annually change their micro-architecture i.e. they went from SIMD(Geforce 4 TI), VLIW (Geforce FX), SIMD (Geforce 6/7),  SIMT(Geforce , MIMT**(Geforce GT300). “Hitting the metal”  requires userland software rewrites.

Hitting the metal can be done and product enhanced.  I still use same I/O ports and memory address of A000:0000 for VGA access on ISA-based VGA cards, VESA-based VGA cards, PCI-based VGA cards, and AGA-based VGA cards.  So they improved the video cards and yet maintained backward compatibility at hardware level.

>The Xbox 360 controller assumes lack of PC keyboard access. Note that, the mouse is one form of analogue control.

But mouse is usually read as digital data so it's more exact than reading an analog value which tends to fluctuate between various values.

>In real world controls, analogue controls reigns supreme.

I wasn't speaking from marketing point of view-- but one of ease of use and learning in a majority of games.

[amigaksi]

Come on, you need more than one button for some games, no amount of programming can make that easier. I don't like the other extreme - the PS1/2/3 controller still annoys me due to the number of buttons. Best controller I've used so far? The Gamecube. Just the right number of buttons, a nice big "Go" button under your thumb, and analogue shoulder buttons that can also be used digitally. But come on, 3 buttons is probably a bare minimum for a lot of games these days to avoid reaching for the keyboard from time to time. I remember hating the Amiga version of Street Fighter compared to the SNES because of the lack of buttons. Less than three might make it easier to play, but imposes tough limits on the flexibility of the game. Hell, I remember Spy Hunter on the Atari 800 had support for a special 2-button joystick (was actually wired as a second joystick's fire button), so you could use 2 different weapons and drive at the same time. It was great!!

You can get away with a couple of buttons by separating the game selection/starting to be separate from the joystick.  Atari 800 had the console keys separate from the joystick button.  Atari 7800 had the two button joysticks.  They would also work on Amiga.

[amigaksi]

let me come at this from a different perspective.

how many chipsets are there currently?

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I know current video/audio boards are NOT backward compatible on hardware level (except basic VGA graphics).  But that trend is with modern systems.  Older PCs did have hardware level compatibility like Amigas.

>you see the original amiga and aga amiga had the advantage of being the same hardware regardless of machine so people were able to get away with banging the hardware while programming. this also stiffled what commodore could have done with their chipsets since they had to maintain hardware backwards compatibility. this is why commodore was trying to move people away from doing that.

Don't see why it would "stifle" things.  Hardware compatibility is a good thing; API-level compatibility is not as good-- slower and harder to compute response time overall.

[amigaksi]

Yeah, I understand that, but what about using 3 different weapons for example? Or a driving game with more than just accelerate/brake? Or even Street Fighter? High punch, middle punch, low punch. An awful pain if you have to combine a button with a joystick movement to choose a different attack. And it rules out attacks while jumping, crouching etc. Yes, 10 buttons is making things overly complicated, but so is limiting yourself to 3 or less. Of course start/pause/reset can be moved away, but sure you don't need more than that anyway - game select screens shouldn't need more than direction and one button.

I guess example of data compression is appropriate here.  If you take majority of games, and take down how many buttons are a must to play, you will end up with a series of number with some maximum and minimum (0 for pacman, 2 for defender, 176 for Flight simulator, etc.).  Now rather than carry lg(MaxButtons-1) bits, you simply use the lg(majority of cases for buttons-1) and have special codes/cases for those exceptions.  So for example, Atari 800 games generally only need one button so in case of Defender they used the Space bar for Smart Bomb and some other key for hyperspace.  That makes it simple for the user to figure out and not need a manual everytime he puts some game in.  Nowadays, you switch games and you have to remember which button did what in addition to making learning curve bigger for each game and less responsive due to bigger choice of options for buttons.