PC keyboard repeat rate vs repeat delay vs release vs press? \ VOGONS

PC keyboard repeat rate vs repeat delay vs release vs press?

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First post, by superfury

Posted on 2016-03-10, 14:14

superfury Offline

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Posts: 5494
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I'm trying to get my PS/2 keyboard emulation correct. I already have basic handlers that convert from the platform (PSP(w/ OSK when used), Windows or Linux) to an universal format used by the keyboard (104 keys as numbers).

So far I've implemented:
- When a key is pressed, it's press count (0-103) is registered and the key is marked as pressed.
- When a key is released, it's marked as released on top of it's pressed status (so both pressed and released when pressed, else nothing happens).

In the timer (ran at a high speed):
- When a key is marked as pressed and released, it immediately sends it's release code to the PS/2 keyboard buffer and marked as unpressed (reset to it's default state).

Then within the same timer, after processing the above information (key releases), it starts checking for input speed and new key presses:
- When no keys are pressed anymore, the step (the delay in 1ms periods between checking for input and processing it) and key_pressed_counter(increasing number, containing 1 more than the last key number pressed. This goes from 0-last key pressed, which is an incrementing number containing the order of key presses (including releases which were pressed)) are cleared.
- Finally, the input is handled:
-- When the current 1ms count (incremented by 1 each interval) exceeds the step (The amount of ms between checking and processing input)), (new) input is handled:
-- The current 1ms count is reset to zero.
-- When keys are pressed:
--- keypresses are handled.
--- The next step is calculated (depending on if there are active keys and step. If step is set, it's set to the repeat rate, else repeat delay)).

The handling of a key press checks the step variable. If it's set it's assumed the key is typematic, else non-typematic.
- Typematic key(s) are handled only the last key pressed (the earlier ones not being resent). When a key is released, the last pressed key becomes the active key (so if you press A,D,S,F, release F then S becomes the active key(the last in the line of active keys order still pressed)).
- Non-typematic key(s) are always pressed (more at one pressed key gets triggered in one loop before returning to the caller).

Is this correct? Or have I made a mistake in my keyboard emulation (PS/2 keyboard)?

https://bitbucket.org/superfury/x86emu/src/2d … ard.c?at=master

Edit: Fixed it according to the official documentation, stopping input when any key is released (including rapid input).

https://bitbucket.org/superfury/x86emu/src/8a … ard.c?at=master

Author of the UniPCemu emulator.
UniPCemu Git repository
UniPCemu for Android, Windows, PSP, Vita and Switch on itch.io

Reply 1 of 4, by Azarien

Posted on 2016-03-10, 20:34

Azarien Offline

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Joined: 2015-05-14, 07:14

Edit: Fixed it according to the official documentation, stopping input when any key is released (including rapid input).

My keyboard stops repeating only when the repeating key is released.

Reply 2 of 4, by superfury

Posted on 2016-03-10, 23:43

superfury Offline

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Posts: 5494
Joined: 2014-03-08, 11:25
Location: Netherlands

Exactly what key is that? The first key pressed or the last key pressed? My emulation currently uses the last key(which repeats while it's pressed and not released). Releasing any key releases all keys but Ctrl, Alt and Shift(both left and right). This makes the input the same as my keyboard(Logitech) within Windows 10's notepad.

Author of the UniPCemu emulator.
UniPCemu Git repository
UniPCemu for Android, Windows, PSP, Vita and Switch on itch.io

Reply 3 of 4, by Azarien

Posted on 2016-03-11, 09:36

Azarien Offline

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Rank: Oldbie
Posts: 886
Joined: 2015-05-14, 07:14

The last key is being repeated, and releasing any other key does not stop it.
Releasing Shift does not stop repetition, but changes the case of repeated character.
Pressing Shift stops repetition.

Reply 4 of 4, by superfury

Posted on 2016-03-11, 10:01

superfury Offline

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So the repitition stops when ctrl/alt/shift is pressed again after repitition. Is this true? Also, does the currently pressed key change to shift repeating, or stop completely? (Although you'll need some kind of input sniffer letting you see the press and release data to do that)?

Also, would any keyboard sniffer be viewed as a Trojan in any antivirus software? Is there any safe one to look at my keyboard packets?

Edit: I've solved this problem by simply logging within my emulator itself (in the onKeyPress and onKeyRelease functions, which get input translated from SDL, which has repeat enabled using it's default settings).

10:00:17:93.7.0597: Keypress:esc
2
30:00:18:02.1.0293: Keyrelease:esc
4
50:00:19:72.0.0794: Keypress:esc
6
70:00:19:78.8.0004: Keyrelease:esc
8
90:00:28:06.8.0477: Keypress:lshift
10
110:00:29:26.8.0053: Keypress:a
12
130:00:29:36.7.0910: Keyrelease:a
14
150:00:29:70.9.0754: Keypress:a
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170:00:29:78.9.0059: Keyrelease:a
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850:00:45:58.2.0810: Keyrelease:a

So this means that releasing non-Ctrl/Alt/Shift stops input, but Ctrl,Alt and Shift aren't repeating? Also, release codes aren't sent until they're actually released on the keyboard (it just stops sending keypress codes(surpresses them) for those keys).

Edit: I've worked a bit on it. It seems to run reasonably well, but with a little strange stuff at the end:
Input data from SDL:

10:00:18:06.1.0679: Keypress:esc
2
30:00:18:13.7.0754: Keyrelease:esc
4
50:00:19:79.7.0212: Keypress:esc
6
70:00:19:83.2.0622: Keyrelease:esc
8
90:00:24:04.0.0475: Keypress:lshift
10
110:00:25:83.7.0382: Keypress:a
12
130:00:26:36.9.0475: Keypress:a
14
150:00:26:39.9.0929: Keypress:a
16
170:00:26:43.1.0264: Keypress:a
18
190:00:26:43.6.0623: Keypress:s
20
210:00:26:96.8.0770: Keypress:s
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230:00:26:99.9.0330: Keypress:s
24
250:00:27:03.0.0712: Keypress:s
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290:00:27:09.2.0412: Keypress:s
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310:00:27:12.3.0335: Keypress:s
32
330:00:27:15.4.0358: Keypress:s
34
350:00:27:18.4.0680: Keypress:s
36
370:00:27:20.7.0507: Keyrelease:s
38
390:00:27:95.4.0545: Keyrelease:a
40
410:00:29:09.7.0084: Keypress:a
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430:00:29:62.9.0440: Keypress:a
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450:00:29:66.0.0518: Keypress:a
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550:00:30:29.0.0944: Keypress:s
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60

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Emulated input:

10:00:18:06.3.0099: Key press: esc
2
30:00:18:13.9.0186: Key release: esc
4
50:00:19:79.8.0657: Key press: esc
6
70:00:19:83.4.0022: Key release: esc
8
90:00:24:04.1.0933: Key press: lshift
10
110:00:25:84.1.0830: Key press: a
12
130:00:26:10.5.0697: Key press: a
14
150:00:26:14.1.0291: Key press: a
16
170:00:26:17.6.0885: Key press: a
18
190:00:26:21.2.0471: Key press: a
20
210:00:26:24.9.0471: Key press: a
22
230:00:26:28.5.0048: Key press: a
24
250:00:26:32.0.0698: Key press: a
26
270:00:26:35.6.0368: Key press: a
28
290:00:26:39.2.0450: Key press: a
30
310:00:26:42.8.0869: Key press: a
32
330:00:26:46.5.0199: Key press: s
34
350:00:26:72.9.0266: Key press: s
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370:00:26:76.4.0861: Key press: s
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550:00:27:09.0.0016: Key press: s
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60

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1590:00:34:64.1.0020: Key press: s
160
1610:00:34:67.6.0778: Key press: s
162
1630:00:34:70.5.0982: Key release: s
164
1650:00:35:00.6.0649: Key press: s
166
1670:00:35:27.1.0399: Key press: s
168
1690:00:35:30.7.0095: Key press: s
170
1710:00:35:34.2.0788: Key press: s
172
1730:00:35:37.9.0873: Key press: s
174
1750:00:35:41.5.0562: Key press: s
176
1770:00:35:45.1.0230: Key press: s
178
1790:00:35:48.6.0955: Key press: s
180
1810:00:35:49.6.0499: Key release: s
182
1830:00:37:88.6.0603: Key release: lshift
184
1850:00:39:16.3.0368: Key release: a
186
1870:00:45:15.1.0575: Key press: lshift
188
1890:00:45:73.7.0963: Key press: a
190
1910:00:46:00.2.0733: Key press: a
192
1930:00:46:03.8.0417: Key press: a
194
1950:00:46:07.4.0101: Key press: a
196
1970:00:46:11.1.0203: Key press: a
198
1990:00:46:14.6.0908: Key press: a
200
2010:00:46:18.2.0588: Key press: a
202
2030:00:46:21.8.0297: Key press: a
204
2050:00:46:25.4.0485: Key press: a
206
2070:00:46:29.0.0862: Key press: a
208
2090:00:46:32.7.0243: Key press: a
210
2110:00:46:36.3.0640: Key press: a
212
2130:00:46:40.0.0233: Key press: a
214
2150:00:46:43.6.0938: Key press: a
216
2170:00:46:47.3.0466: Key press: a
218
2190:00:46:51.1.0280: Key press: a
220
2210:00:46:54.7.0698: Key press: a
222
2230:00:46:58.4.0115: Key press: a
224
2250:00:46:62.0.0512: Key press: a
226
2270:00:46:65.7.0020: Key press: a
228
2290:00:46:68.2.0391: Key release: lshift
230
2310:00:49:83.7.0940: Key release: a
232
2330:00:49:83.8.0431: Key press: lshift
234
2350:00:49:83.9.0447: Key release: lshift

Source code of the keyboard emulation: https://bitbucket.org/superfury/x86emu/src/a6 … ard.c?at=master

Anyone can see what's going wrong here? Or is this simply because SDL uses the default rate(for delay and repeat), while my application use what is set by the BIOS+MS-DOS 5.0?

Author of the UniPCemu emulator.
UniPCemu Git repository
UniPCemu for Android, Windows, PSP, Vita and Switch on itch.io

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