Firefox "minimize memory"

 One of the things I do is have a lot of open tabs, and firefox happily fills up all the available memory.

If you go to "about:memory" and click on "minimize memory usage" it will free up some much needed memory.

After clicking on this my total memory usage went from 31GB to 21GB.

Switching audio and adding a notification

 Once you get the audio switching working, it's nice to have a little bit of feedback, so add a little message with notify-send.

so CTRL+ALT+9 does

sh -c "pactl set-card-profile 0 output:hdmi-stereo;notify-send 'switch to hdmi'"

 

and CTRL+ALT+0 does:

 sh -c "pactl set-card-profile 0 output:analog-stereo; notify-send 'switch to headphone'"

Thanks to this page:

https://askubuntu.com/questions/60379/how-to-combine-two-commands-as-a-launcher

Switching the audio from HDMI to headphones

One of the things I do too frequently is to switch from my headphone output to the hdmi output. It's too hard to use the control panel, I want a keystroke to do it: 

After wrestling with pactl awhile I got it working.

 

If you run "pactl list cards" It will show you a list of profiles:

 "pactl set-card-profile 0 output:hdmi-stereo" 

"pactl set-card-profile 0 output:analog-stereo" 

would switch between the different outputs, so just add some Keyboard Shortcuts in the Settings.

Sometimes I have to kill gnome shell

Using Ubuntu 20.04, sometimes the screen will go black and I can't do anything. I can still see my mouse pointer and move it around, I can drop to a text console with CTRL+ALT+F4 and back with CTRL+ALT+F2 but it's not working right. I've found that if I get to a text console and login and then find the number of the gnome-shell process with "ps -ax | grep gnome-shell" then "kill -9 " it will close the gnome-shell and after a few seconds the system will relaunch it, bringing the system back to normal. It doesn't always work, but sometimes it's a lifesaver when it goes non responsive and you can save what you were working on.

Search tabs in firefox with %

Here's something I'm using a lot.

If you type % in the location box, you can search among your open tabs.

This is really useful when you've got a lot of open tabs.

So if I want to find that usps tab, just type "%usps" for example, and it will show it in the drop down list.

I discovered this when moving the list all tabs button to the left side of the tabs using customize because it kept on disappearing from the right side of the tabs. When you click on the list all tabs, the second entry is search tabs and it puts a % into the location box.

Multi-monitor shortcuts under Ubuntu

One of the best things to know with Ubuntu and multi monitors is to know the shortcuts to move windows from monitor to monitor.

Shift+Windows key and arrows will move a window to a different monitor (in the direction of the arrow).

I guess Ubuntu's term for the windows key is Super, so Shift+Super+arrows.


My TV tends to shut itself off during power save so instead of turning it back on, I'll just shift the window I need back in view.


It beats typing "alt+spacebar then down arrow then down arrow and enter" to activate the window move operation and then using the mouse or arrow keys to bring it back into view.

I've been using ubuntu for years without knowing these useful keystrokes.

2mm leads from golf pencils

I had a couple of golf pencils that broke in half that exposed the lead inside. It's a 2mm lead so it doesn't fit anything, so how to use it?




At the Dollar Tree, they sell these neat colored pencils that use 2mm leads.

I thought, they're 2.0 mm so why not see if the lead fits, and sure enough it does. These pencils have a sharpener in the top so you can sharpen the tip of the lead.

So just break a golf pencil in half for a new lead.

Lenovo dual DVI usb 3.0 dock and Ubuntu

I got this Lenovo dual dvi usb 3.0 dock and thought I'd see if I could get it running with my Ubuntu 19.10 laptop.

After getting the drivers from displaylink, I gave it a try. What I noticed was that I'd get weird pointer trails and the display wouldn't update perfectly.

I hooked up my 50" tv to the DVI on the dock with a DVI to HDMI cable. But half the time I'd activate the TV, the computer would just freeze.

I gave up on it for awhile, but then realized that if I had the TV on when I started up the computer, everything was fine, no pointer trails and no crashes.


So now I've got 2 monitors on the lenovo displaylink dock, and 2 monitors off the laptop's outputs (HDMI and VGA) plus the laptop's own monitor (the 3 running off the integrated intel graphics).





5 total monitors works pretty nicely. Just remember to have the monitors on the displaylink turned on when you boot.



The only thing that's irritating now is that when I boot with the dock, ubuntu switches the audio volume controls to the dock. I still get audio output from the laptop but I can't control the volume until I set the audio output back to the built-in. It'd be cool to be able to "lock" the audio to a specific output and prefer that setting.

Also TVs tend to shut themselves off when they have no signal from power saving, and every time I turn the TV back on, the video system detects this and all the screens go black for a moment. Here's another case where it'd be good to have a mode where it wouldn't try to do anything when a new monitor gets detected, just leave things the way they were.

Jgrasp and Focus Follows Mouse

I was fiddling with the Java IDE Jgrasp on Ubuntu and one of the things that had been driving me crazy was the setting for "focus follows mouse".

No matter how careful I am, my mouse would end up drifting into some other jgrasp pane and my typing would be lost.

I finally found the setting for it, hidden under the menu Settings/Desktop/Focus Follows Mouse and it was unselected.

This was a little baffling so I checked it and unchecked it. That seemed to fix it. Yes!

Tools key brings up settings in Ubuntu 19.10

One of the things I really liked to do was to set up my keyboard's Tools Key to put the computer into suspend. On my dell keyboard (y-uk-del1), the Tools key is a special key that has a little Music Symbol on it.

But after upgrading to Ubuntu 19.10 the Tools key will now bring up the settings window. So what to do?

All I had to do was to set the shortcut to Super+Tools which did the trick, or find another key to do it. There's a special "Home Page" key on the function row that works as well.


I wanted them both to do the suspend action but you can only assign a single shortcut key, so why not create two custom shortcuts, one for each key.





Also I discovered that you can put the computer into suspend by holding down the mouse button over the power button in the System Menu. Then the power button changes into a pause symbol. Holding down alt also works to choose suspend instead of power off.

Fiddling with the Matrox DualHead2Go on ubuntu

I saw one of these on ebay so I thought I'd give it a spin. I got the dualhead2go digital edition which has VGA input and dual DVI outputs.

If you don't know what a DualHead2Go is, it takes a video signal in and splits it across 2 monitors, effectively giving you an additional monitor out. The catch is that your computer video card must output a very high VGA resolution, 3840x1080 if you want dual 1920x1080 monitors.

On my laptop with Ubuntu 19.04 that has integrated intel graphics, it will only output 2*1360x768 (2720x768) resolution on the VGA port. Anything higher and I get "failed to configure crtc1".

These are all of the different resolutions supported by the DualHead2go:


single standard landscape



single monitor wide landscape





dualhead wide landscape




dualhead standard portrait



dualhead wide portrait




There's a limit of 4 settings that you can preset. These will show up on the matrox's EDID.

So after enabling 3480x1080 double 1920x1080 ,2560x1600 (double 1280x800 portrait), 2720x768 (double 1360x768)
the edid returns:

(if you don't have get-edid then sudo apt install read-edid)

sudo get-edid | parse-edid

Section "Monitor"
Identifier ""
ModelName ""
VendorName "MTX"
# Monitor Manufactured week 30 of 2005
# EDID version 1.3
# Analog Display
Option "SyncOnGreen" "true"
# Display Physical Size not given. Normal for projectors.
Gamma 2.20
Option "DPMS" "true"
#Not giving standard mode: 1600x1200, 60Hz
#Not giving standard mode: 1280x1024, 60Hz
Modeline "Mode 0" 261.01 3840 3856 3904 3920 1080 1083 1094 1111 +hsync -vsync
Modeline "Mode 1" 271.00 2560 2608 2640 2744 1600 1603 1615 1646 +hsync -vsync
Modeline "Mode 2" 171.00 2720 2848 2960 3584 768 771 774 795 +hsync +vsync
EndSection



matrox powerdesk



There's options to swap displays, adjust image quality




I used an old windows vista machine and installed PowerDesk to set the settings on the box. It wants a good signal going into it so I left my ubuntu system plugged into the VGA generating a signal, while the USB was plugged into the windows vista box. If there's no VGA signal going into the box, PowerDesk won't let you set the modes in the mode management settings. As long as there's a signal, even if it's not originating from the vista box, you're fine. Once you've programmed the settings on the box, you can disconnect the usb from the vista box. You do need to plug in the usb to a usb port to get power.

So the big problem is one of getting a VGA signal of sufficiently hi-res, namely 3840x1080. My laptop with ubuntu 19.04 and intel graphics would only do 2720x768. What about another machine?

I installed Ubuntu 19.10 on another system with an Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz. The integrated graphics would come up at 3840x1080 but for some reason, the acceleration was nonexistent. It was so slooooooooow, the system was running but it was slow. I did have an idea, why not try wayland? Selecting wayland at the boot screen came up fine with acceleration. Awesome.

There's also an AMD Cedar graphics card in this system, and strangely it wouldn't go higher than 2720x768. 3840x1080 would give me a black screen. Oddly, booting this same system under knoppix 8.6.1 livecd would give the 3840x1080 resolution on the AMD Cedar.


00:02.0 Display controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cedar [Radeon HD 5000/6000/7350/8350 Series]


One of the things about an ultrawide screen is that youtube fullscreen is problematic, since it splits it across two monitors. I wish that fullscreen could be setup to go to the left side or the right side of the full double-monitor.

Adjusting the image quality needed a "special image" so I made my own in gimp by hand. It's an 3840x1080 image of alternating black and white lines.
Once I made this image, I just viewed it in fullscreen with eog, hitting f11 to go fullscreen.



The full image doesn't come through with blogger's image system, so here's a piece of it if you want to make your own 3840x1080 by stitching:



I tried to snapshot the image display when PowerDesk would overlay the desktop with the alternating lines, but the PrintScreen key would just give me the normal desktop. I don't know if my version works as intended but I hope it does.

Someday, they'll have sorted the high resolution VGA outputs on linux, I suppose most people don't have any use for such resolutions as most people don't have matrox DualHead2Gos.

XSane preview window bug and failed to start scanner invalid argument

I had a problem the other day with XSane.

It's been working awesome and then one day, the preview window wouldn't come up properly, basically a blank window.

And then I couldn't scan anything, getting an error dialog that said "Failed to start scanner: Invalid argument".





This was driving me crazy, I power cycled the hp printer/all in one 5740 but it wouldn't work at all.


So let's see if we can scan with scanimage.

scanimage -d hpaio:/net/Officejet_5740_series?ip=192.168.1.10 --format=tiff > mytest2.tiff


That worked! So why was I getting the invalid argument error? Looking carefully I saw that the area to scan was set to basically zero. The rectangle specified was basically of zero area. If you look at the top left it's set to 8.5 and 11.69 and the bottom right is 8.5 and 11.69. I must have clicked somewhere in the "blank" preview window that set these coordinates.

It'd be nice if it said "Scan Area Coordinates invalid" instead of just "invalid argument".


I see that other people have been having the same bug with the preview window:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=867667

What's interesting is that opening the preview window with CTRL+1 seems to have fixed it. Opening it with the menu Window/Show Preview was giving me the blank screen.


Anyway, I can happily scan again!


Just for fun, let's see how small a region we can actually scan without getting the "Failed to start scanner: Invalid argument" error.


The smallest I can scan is 1x1x24 (3.0B) for 3 bytes!

Weirdness with VGA to HDMI adapter and i915

So I've got an older TV that I wanted to use with a laptop and do triple monitors. The laptop has got its own 1600x900 built-in screen, and on the hdmi port I've connected a DVI 1920x1200 monitor and then there's a Toshiba 40FT1U on the VGA port.

The only problem is that the Toshiba 40FT1U doesn't like anything higher than 1280x1024 or 1366x768 on the VGA port. Checking with the manual, sure enough that's the maximum on VGA-in but HDMI-in will give you the full 1080p resolution.



I got on ebay and found a cheap VGA to HDMI adapter. The only problem is that I couldn't get Ubuntu 19.04 to output a video signal that xrandr would like.

The VGA to HDMI adapter had no EDID information, and get-edid wouldn't return anything.

Firing up cvt 1920 1080 60, I would make an xrandr newmode of 1920x1080.

$ cvt 1920 1080 60
# 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz
Modeline "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 1083 1088 1120 -hsync +vsync
$ xrandr --newmode "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 1083 1088 1120 -hsync +vsync
$ xrandr --addmode VGA-1 "1920x1080_60.00"
$ xrandr --output VGA-1 --mode "1920x1080_60.00"
xrandr: Configure crtc 1 failed

Sadly, that didn't work at all giving a "Configure crtc 1 failed" message.

Looking at my xorg log it says just Invalid argument:

$ less ~/.local/share/xorg/Xorg.0.log 
[   405.766] (II) modeset(0): Allocate new frame buffer 5440x1200 stride
[  1196.778] (EE) modeset(0): failed to set mode: Invalid argument

What's strange is that I can do a resolution of 1912x1080:

$ cvt 1912 1080 60
# 1912x1080 59.91 Hz (CVT) hsync: 67.10 kHz; pclk: 171.25 MHz
Modeline "1912x1080_60.00"  171.25  1912 2032 2232 2552  1080 1083 1093 1120 -hsync +vsync
$ xrandr --newmode "1912x1080_60.00"  171.25  1912 2032 2232 2552  1080 1083 1093 1120 -hsync +vsync
$ xrandr --addmode VGA-1 "1912x1080_60.00"
$ xrandr --output VGA-1 --mode "1912x1080_60.00"

So 1912x1080x60 works no problem, which is really strange. The only problem is that my VGA to HDMI adapter scrunches the screen horizontally, which is usable but it offends me terribly. Not having 1 to 1 pixels grated on me.

I've got another television a 50 inch emerson with a VGA input, and weirdly, plugging the VGA into it allows me to set a 1920x1080x60 resolution. Oddly, it has no EDID information either but the 1920x1080 resolution will work.


So I thought, let's see if we can get a working edid from another monitor and use that.

On another system with a sceptre monitor that was 1920x1080 I ran "sudo get-edid > sceptre_edid.bin".

Then I made a /usr/firmware/edid directory with "sudo mkdir /usr/firmware/edid" then "sudo cp sceptre_edid.bin /usr/firmware/edid/"/

Locating the file /etc/default/grub and running "sudo nano /etc/default/grub"

and making these changes:
GRUB_TIMEOUT=10
GRUB_TIMEOUT_STYLE=menu

GRUB_CMDLINE_LINUX=" drm.edid_firmware=VGA-1:edid/sceptre_edid.bin"

then "sudo update-grub"

and now it comes up just fine with 1920x1080 on the VGA-1 port.

So what is actually not working? Let's take a closer look at the EDID file with parse-edid.

$ cat sceptre_edid.bin | parse-edid
Checksum Correct

Section "Monitor"
 Identifier "E275W-1920"
 ModelName "E275W-1920"
 VendorName "SPT"
 # Monitor Manufactured week 6 of 2015
 # EDID version 1.3
 # Analog Display
 Option "SyncOnGreen" "true"
 DisplaySize 600 340
 Gamma 2.20
 Option "DPMS" "true"
 Horizsync 30-95
 VertRefresh 56-75
 # Maximum pixel clock is 180MHz
 #Not giving standard mode: 1280x800, 60Hz
 #Not giving standard mode: 1280x960, 60Hz
 #Not giving standard mode: 1280x1024, 60Hz
 #Not giving standard mode: 1440x900, 60Hz
 #Not giving standard mode: 1600x1200, 60Hz
 #Not giving standard mode: 1680x1050, 60Hz
 Modeline  "Mode 0" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync 
 Modeline  "Mode 1" 118.97 1600 1712 1864 2112 900 901 904 932 -hsync +vsync 
EndSection

That modeline of "Mode 0" is 1920x1080 but the numbers are different from what cvt gives:


Comparing the two modelines, the numbers vary slightly and the hsync is opposite polarity.

Modeline "1920x1080_60.00"  173.00   1920 2048 2248 2576   1080 1083 1088 1120 -hsync +vsync
Modeline "Mode 0"           148.50   1920 2008 2052 2200   1080 1084 1089 1125 +hsync +vsync

Let's compare it to a reduced blanking modeline from cvt, now you'll notice that the vsync is opposite.

$ cvt 1920 1080 60 -r
# 1920x1080 59.93 Hz (CVT 2.07M9-R) hsync: 66.59 kHz; pclk: 138.50 MHz
Modeline "1920x1080R" 138.50 1920 1968 2000 2080 1080 1083 1088 1111 +hsync -vsync
Modeline "Mode 0" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync



So I tried rebooting ubuntu *without* the drm.edid_firmware=VGA-1:edid/sceptre_edid.bin and it went right back to hating my cvt 1920 1080 60 modeline.

But let's try the modeline from the sceptre edid "Mode 0".

$ xrandr --newmode "Mode 0" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
$ xrandr --addmode VGA-1 "Mode 0"
$ xrandr --output VGA-1 --mode "Mode 0"

Hah! It likes that modeline!

It also seems to like the reduced blanking version.

$ cvt -r 1920 1080 60
# 1920x1080 59.93 Hz (CVT 2.07M9-R) hsync: 66.59 kHz; pclk: 138.50 MHz
Modeline "1920x1080R" 138.50 1920 1968 2000 2080 1080 1083 1088 1111 +hsync -vsync
$ xrandr --newmode "1920x1080R" 138.50 1920 1968 2000 2080 1080 1083 1088 1111 +hsync -vsync
$ xrandr --addmode VGA-1 "1920x1080R"
$ xrandr --output VGA-1 --mode "1920x1080R"


I also tried gtf and that didn't work. xrandr: Configure crtc 1 failed

Strangely, using drm.edid_firmware=VGA-1:edid/1920x1080.bin would work on the VGA to HDMI but for some reason I'd lose the other monitor.
(This would use a "built-in" 1920x1080 edid file)


The actual 1920x1080 timings can vary, here's a couple of monitors that have 1125 as the last number of the modeline.


From https://cdn.kramerav.com/web/downloads/white-papers/analog_edid_whitepaper_6.pdf:

"Knowing that the standardization problem exists mostly in widescreen resolutions, let us look at an example using 1920x1080.
These mode lines came from the EDIDs of the computer graphics video inputs of different 1080p monitors:"

Monitor 1 – LG LCD 
• Detailed timing #1....... 1920x1080p at 60Hz (16:9) 
• Mode line............... “1920x1080” 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync 
Monitor 2 – Westinghouse LCD 
• Native/preferred timing.... 1920x1080p at 60Hz (16:9) 
• Mode line............... “1920x1080” 138.500 1920 1968 2000 2080 1080 1082 1087 1111 +hsync -vsync 
Monitor 3 – Samsung LCD 
• Native/preferred timing.. 1920x1080p at 60Hz (16:9) 
• Mode line............... “1920x1080” 138.500 1920 1968 2000 2080 1080 1083 1088 1111 +hsync -vsync 
Monitor 4 – Panasonic Plasma 
• Detailed timing #1....... 1920x1080p at 60Hz 
• Mode line............... “1920x1080” 148.500 1920 2008 2052 2200 1080 1084 1089 1125 -hsync –vsync 
Monitor 5 – Vizio LCD 
• Native/preferred timing.. 1920x1080p at 60Hz 
• Mode line............... “1920x1080” 136.500 1920 1952 1984 2048 1080 1081 1084 1111 +hsync +vsync 

"You can clearly see that while all these monitors claim to be 1920x1080 monitors, they each support a different version of 1920x1080. It is also clear that describing active pixels alone is not specific enough to define a resolution. Display manufacturers have taken to producing non-standard displays, because the specific timings are completely described in the EDID of the monitors they build. When a computer is connected directly to any of these monitors, the mode line is read by the PC and automatically the PC modifies its output to comply properly with that display."



Now with the edid file I can get my VGA to HDMI adapter to work with full 1920x1080 resolution automatically or using the "Mode 0" modeline from the edid file I can get xrandr to work. The VGA to HDMI output really looks good on the tv.

Non blocking reads in lua

So I wanted to try reading some midi data from my keyboard with lua and ubuntu. I installed lua 5.3 and lua posix with "sudo apt install lua5.3 lua-posix"


Then I plugged in my M-Audio Keyrig 49 to the usb and tested it with "aseqdump -l" to list the midi devices then "aseqdump -p 24:0" since it came up on port 24:0.

Ok, so now for the lua (something quick and hacky to test it):

The keyrig will generate 0x90 key on and always 3 bytes for each midi message (0x90 status, then pitch, the velocity) so that makes it really easy.

posix = require("posix")

j={}

function printj() if j==nil then j={} end for i=12*3,12*7 do if j[i]==nil or j[i]==0 then io.write(".") else io.write("*") end end print() end

processbyte=coroutine.create(function(b) if j==nil then j={} end while true do print(b) b=coroutine.yield() if string.byte(b)==0x90 then b=coroutine.yield() key=string.byte(b) b=coroutine.yield() velocity=string.byte(b) j[key]=velocity  print("KEY="..key,"VELOCITY="..velocity) printj() end end end)


f = posix.open("/dev/midi2",posix.O_RDONLY|posix.O_NONBLOCK)
print("file is "..f)
while true do 
a = posix.read(f,1) 
if a ~= nil then print(string.format("%x",string.byte(a))) coroutine.resume(processbyte,a) 
else  posix.rpoll(f,10)
end 
end

-- when done, just do a posix.close(f)

and some sample output:

................................................

90
3b
39
KEY=59 VELOCITY=57
.......................*.........................
9
90
3c
36
KEY=60 VELOCITY=54
.......................**........................
6
90
3e
23
KEY=62 VELOCITY=35
.......................**.*......................

MTU 80 Column 3d hat

I remember this program that I typed in from a magazine years ago that would draw a neat 3d function. So let's see if we can find it:


https://j-b.livejournal.com/268176.html
Atari 8-bit "Archimedes Spiral" demo - FOUND!

I searched google for:
mtu commodore pet graphics "high-resolution"
which led me to an ebay ad and if you look closely it says "May 1981" so let's see what we can find for ads for MTU in may 1981.





Micro, the 6502 magazine, may 1981 page
http://archive.6502.org/publications/micro/micro_36_may_1981.pdf

I found the original source for the ebay ad picture:

https://archive.org/details/creativecomputing-1981-05/page/n67





And another page that mentions the MTU ad and rewriting it in 68000

http://www.easy68k.com/paulrsm/dg/dg07.htm


It was originally for the PET with a MTU graphics board, but it wasn't hard to convert to Apple II Applesoft Basic, but I kept getting illegal quantity errors on the hplots being outside of the range 0-279 for x and 0-191 for y so there's code to keep them within range.

You can paste the program into mame's lua console and then unthrottle with F10 and set the frameskip to skip 10/10 it to run it really fast. If you shrink the mame window it will go even faster. I think I can get it to 1200% on my system so it only takes about 8 minutes.

emu.keypost([[
   NEW
 10 HGR2 : HCOLOR=3
 20 P=160 : Q=100
 30 XP=120:XR=1.5*3.1415927
 40 YP=56:YR=1:ZP=64
 50 XF=XR/XP:YF=YP/YR:ZF=XR/ZP
 60 FOR ZI=-Q TO Q-1
 70 IF ZI<-ZP OR ZI>ZP GOTO 150
 80 ZT=ZI*XP/ZP:ZZ=ZI
 90 XL=INT(.5+SQR(XP*XP-ZT*ZT))
 100 FOR XI=-XL TO XL
 110 XT=SQR(XI*XI+ZT*ZT)*XF:XX=XI
 120 YY=(SIN(XT)+.4*SIN(3*XT))*YF
 130 GOSUB 170
 140 NEXT XI
 150 NEXT ZI
 160 STOP
 170 X1=XX+ZZ+P
 180 Y1=YY-ZZ+Q
 181 IF Y1<1 THEN Y1=1  : REM MUST BE 1 OR ERROR IN 210
 182 IF Y1>191 THEN Y1=191
 183 IF X1<0 THEN X1=0
 184 IF X1>279 THEN X1=279
 190 HCOLOR=3:HPLOT X1,191-Y1
 210 HCOLOR=0:HPLOT X1,191-(Y1-1) TO X1,191-0
 220 RETURN
 RUN
]])


I also like this applesoft program to plot the gaussian distribution in 3d on codegolf:

https://codegolf.stackexchange.com/questions/123039/plot-the-gaussian-distribution-in-3d/123079

Some Ubuntu resume weirdness, lose mouse, sound

For some reason, I keep losing my mouse on resume. I can unplug it from the top of my keyboard and then plug it in and it will come back. I've also noticed that it will come back properly if I keep moving the mouse during the resume process, until the screen comes back and I can see the mouse moving. What's weird when it happens is that the scroll wheel works, but I can't move the mouse at all until doing an unplug/replug cycle.


Also sometimes I will lose my sound which is pretty irritating.



https://superuser.com/questions/845645/pulseaudio-how-to-rescan-audio-devices


https://askubuntu.com/questions/517578/no-sound-after-suspend-standby

This command will re-detect the sound devices:


pacmd unload-module module-udev-detect && pacmd load-module module-udev-detect



Also you can ask alsa to force reload itself, just doing sudo alsa force-reload didn't bring my sound back, I also had to do the pacmd unload-module module-udev-detect && pacmd load-module module-udev-detect.



sudo alsa force-reload
cat /proc/asound/cards
pacmd list-sinks
pacmd unload-module module-udev-detect && pacmd load-module module-udev-detect
pacmd list-sinks


Stellar 7 text font at 0x7900

I found the text font at 0x7900. It goes from character 32 (space) to 127. 126 and 127 are tiny flag symbols.

and we can write some lua to write some text to the screen:

cpu = manager:machine().devices[":maincpu"];mem = cpu.spaces["program"]

function calc(line) return line % 8 * 1024 + math.floor(line / 64) * 40 + math.floor((line%64) / 8) * 128 +8192 end

function writechar(c,x,y) for i=0,7 do  mem:write_u8(calc(y+i)+x,mem:read_u8(0x7900+i+8*(string.byte(c)-32))) end end

for c=32,127 do writechar(string.char(c),c % 40 ,math.floor(c/40)*8) end

mystr = "ABCDEFGHJKLMNOPQRSTUVWXYZ[]ab"..string.char(126)..string.char(127) ; for j = 1,string.len(mystr) do writechar(string.sub(mystr,j,j),j,16*8) end

mystr = "STELLA! STELLA!  "..string.char(126)..string.char(127) ; for j = 1,string.len(mystr) do writechar(string.sub(mystr,j,j),j,17*8) end

More COS routine multiply analysis.

Binary math really melts my brain. I'm not really designed to function in binary so I've been trying to figure out how the multiply routine ends up with a costable value * multiplicand *2.


I think it's useful to build a model to see exactly what's happening with the bits.

function hex(a,digits) if a==nil then return nil end digits=digits or 2 return string.format("%0"..digits.."x",a) end

function bin(x,numbits,gap) if x==nil then return nil end gap=gap or "_" numbits=numbits or 8 str="" for i=numbits-1,0,-1 do str=str..iif((x&(2^i))~=0,"1","0")..iif((i%8==0) and (i>0),gap,"") end return str end

function bool10(a) return iif(a,1,0) end

function iif(a,b,c) if a then return b else return c end end 

function rem(a) end
function remp(a) print(a) end

function rol8(a,carry) local oldcarry print("ROL8 BEFORE= "..hex(a).."  carry= "..carry.."  "..bin(a)) oldcarry=carry carry=a&1 a=math.floor(a/2)+oldcarry*128 print("ROL8 AFTER = "..hex(a).."  carry= "..carry.."  "..bin(a)) return a,carry end
function lsr8(a,carry) oldcarry=0 carry=a&1 a=math.floor(a/2)+oldcarry*128 return a,carry end
function adc8(a,x,carry) a=a+x+carry carry=bool10((a&0x100)~=0) a=a&0xff return a,carry end 


remp("7 bits of multiplier") mem00=0x7f mem01=0xff remp("mem00="..hex(mem00)) remp("mem01="..hex(mem01)) carry=0 remp("LDX $01="..hex(mem01)) mem01=mem01-1 remp("DEX") remp("STX $01="..hex(mem01)) a=mem00 remp("LDA $00="..hex(mem00)) a,carry=lsr8(a) print("LSR A="..hex(a)) mem02=a remp("STA $02="..hex(mem02)) a=0 remp("LDA #$00 a="..hex(a))  for i=0,6 do if carry~=0 then remp("BEFORE ADC $01="..hex(mem01).."  a="..hex(a).." "..bin(a)) remp("ADD    ADC (c="..carry.."+$01)="..hex(mem01+carry).." "..bin(mem01+carry)) a,carry=adc8(a,mem01,carry) print("AFTER  ADC $01="..hex(mem01).."  a="..hex(a).." "..bin(a).." c="..carry) end print("BEFORE ROL: "..bin(carry,1).."_"..bin(a).."_"..bin(mem02).."" ) a,carry=rol8(a,carry) mem02,carry=rol8(mem02,carry) print("AFTER ROL:  "..bin(carry,1).."_"..bin(a).."_"..bin(mem02).."" ) print(carry,hex(a),bin(a,8),hex(mem02),bin(mem02,8)) end

And if I run this in mame's lua console I can better see where all those bits are going:

7 bits of multiplier
mem00=7f
mem01=ff
LDX $01=ff
DEX
STX $01=fe
LDA $00=7f
LSR A=3f
STA $02=3f
LDA #$00 a=00
BEFORE ADC $01=fe  a=00 00000000
ADD    ADC (c=1+$01)=ff 11111111
AFTER  ADC $01=fe  a=ff 11111111 c=0
BEFORE ROL: 0_11111111_00111111
ROL8 BEFORE= ff  carry= 0  11111111
ROL8 AFTER = 7f  carry= 1  01111111
ROL8 BEFORE= 3f  carry= 1  00111111
ROL8 AFTER = 9f  carry= 1  10011111
AFTER ROL:  1_01111111_10011111
1 7f 01111111 9f 10011111
BEFORE ADC $01=fe  a=7f 01111111
ADD    ADC (c=1+$01)=ff 11111111
AFTER  ADC $01=fe  a=7e 01111110 c=1
BEFORE ROL: 1_01111110_10011111
ROL8 BEFORE= 7e  carry= 1  01111110
ROL8 AFTER = bf  carry= 0  10111111
ROL8 BEFORE= 9f  carry= 0  10011111
ROL8 AFTER = 4f  carry= 1  01001111
AFTER ROL:  1_10111111_01001111
1 bf 10111111 4f 01001111
BEFORE ADC $01=fe  a=bf 10111111
ADD    ADC (c=1+$01)=ff 11111111
AFTER  ADC $01=fe  a=be 10111110 c=1
BEFORE ROL: 1_10111110_01001111
ROL8 BEFORE= be  carry= 1  10111110
ROL8 AFTER = df  carry= 0  11011111
ROL8 BEFORE= 4f  carry= 0  01001111
ROL8 AFTER = 27  carry= 1  00100111
AFTER ROL:  1_11011111_00100111
1 df 11011111 27 00100111
BEFORE ADC $01=fe  a=df 11011111
ADD    ADC (c=1+$01)=ff 11111111
AFTER  ADC $01=fe  a=de 11011110 c=1
BEFORE ROL: 1_11011110_00100111
ROL8 BEFORE= de  carry= 1  11011110
ROL8 AFTER = ef  carry= 0  11101111
ROL8 BEFORE= 27  carry= 0  00100111
ROL8 AFTER = 13  carry= 1  00010011
AFTER ROL:  1_11101111_00010011
1 ef 11101111 13 00010011
BEFORE ADC $01=fe  a=ef 11101111
ADD    ADC (c=1+$01)=ff 11111111
AFTER  ADC $01=fe  a=ee 11101110 c=1
BEFORE ROL: 1_11101110_00010011
ROL8 BEFORE= ee  carry= 1  11101110
ROL8 AFTER = f7  carry= 0  11110111
ROL8 BEFORE= 13  carry= 0  00010011
ROL8 AFTER = 09  carry= 1  00001001
AFTER ROL:  1_11110111_00001001
1 f7 11110111 09 00001001
BEFORE ADC $01=fe  a=f7 11110111
ADD    ADC (c=1+$01)=ff 11111111
AFTER  ADC $01=fe  a=f6 11110110 c=1
BEFORE ROL: 1_11110110_00001001
ROL8 BEFORE= f6  carry= 1  11110110
ROL8 AFTER = fb  carry= 0  11111011
ROL8 BEFORE= 09  carry= 0  00001001
ROL8 AFTER = 04  carry= 1  00000100
AFTER ROL:  1_11111011_00000100
1 fb 11111011 04 00000100
BEFORE ADC $01=fe  a=fb 11111011
ADD    ADC (c=1+$01)=ff 11111111
AFTER  ADC $01=fe  a=fa 11111010 c=1
BEFORE ROL: 1_11111010_00000100
ROL8 BEFORE= fa  carry= 1  11111010
ROL8 AFTER = fd  carry= 0  11111101
ROL8 BEFORE= 04  carry= 0  00000100
ROL8 AFTER = 02  carry= 0  00000010
AFTER ROL:  0_11111101_00000010
0 fd 11111101 02 00000010
[MAME]> 
[MAME]> print(hex(0xff * 0x7f * 2))
fd02
[MAME]> 

Cos and Sin multiplication routine at 0xD00.

So let's disassemble Stellar 7's cos and sin multiplication routine and write it to a file with the dasm command.

dasm d00_multiplication_dasm.txt,d00,f6

This will dissassemble from d00-df5.


As input, it takes the number to be multiplied in $00, the angle in A.

As output, the COS(A) * $00 goes in $22-23 and the SIN A goes in $24-25. The high byte of the output will always be zero. The multiplication generates 16 bits, we're only interested in the high byte, the remainder goes in $02 but it is just ignored.

Another thing to note is that the cos table values are 7 bits with the high bit used as a sign bit.
The cos table represent fractions from 0 to 80.

0x0 represents 0.0 and 0x80 represents 1.0.

But we only have 7 bits, from 0 to 0x7F, we can't actually get 1.0. That's why we've got the special case handling of the angles at 0,90,180 and 270 degrees.

0x7f divided by 128 gets pretty close to 1.0, about 99.2%.

print (0x7f/0x80)
0.9921875

The multiplication routine multiplies by the 7 bits of the lookup table value and then multiplies that by 2.

Therefore our multiplication routine can only get up to multiplying by 0x7f * 2 = 0xfe or 254.

===============================

Example: multiplying by 0x7f or (.992)

So for example, let's take a number, say 0x19 and multiply it by 0x7F and then multiply it by 2. We get

print (string.format("%x",0x7f*0x19*2))
18ce

We take the result of 0x18CE, throw away the low byte of the result 0xCE and we get 0x18 which is 99% of 0x19.


Example: multiplying by 0x40 or (0.5)

So for another example, let's take our same number, say 0x19 and multiply it by 0x40 and then multiply it by 2. We get

print (string.format("%x",0x40*0x19*2))
c80

We take the result of 0xC80, throw away the low byte of the result 0x80 and we get 0xC which is 0.5 * 0x19 or 0xC. 0x19=25 0xC=12.

Basically what we're doing is multiplying by our cos value fraction (0 to 255) and then shifting that result by 8 bits (dividing by 256 by throwing away the low byte).

result = (multiplicand * ((cosvalue AND 0x7f) * 2) / 256

The sign bit is handled specially, we just negate the result by EOR #$FF and ADC #$00 (with the sign bit set, effectively adds by 1).

==================================

Special cases:

First thing we do is to look and see if the number is zero. If so, then we can just put #$00 in $22-23 and $24-25 and rts.

At 0d0d, there's a TAY make a copy of the angle and store it in Y.

We and it with #$3f to check to see if it's any of the special angle cases, 0,0x40,0x80,0xc0 or 0,90,128,192 degrees. If A is zero after anding with #$3f, then we know it's a special case and we jmp to $0db3.

The special cases are pretty straightforward, if the angle is 0, cos 0 = 1, sin 0 = 0. Therefore at $0db6 we copy $00 to $22, put #$00 in $23,$24 and $25.

If the angle is 90, cos 90=0, sin 90=1.

If the angle is 180, cos 180=-1, sin 180=0. So return negative $00 in $22-23, #$00 in $24-25.

If the angle is 270, cos 90=0, sin 90=-1, at $0de6 we put #$00 in $22-23 and we do a subtraction of $00 from #$00 and put that in $24 (ldx #$00,txa,sec,sbc $00,sta $25) and put #$FF in $25 (ldx #$00,dex and stx $25).

0D00: A6 00    ldx $00
0D02: D0 09    bne $0d0d
0D04: 86 22    stx $22
0D06: 86 23    stx $23
0D08: 86 24    stx $24
0D0A: 86 25    stx $25
0D0C: 60       rts
0D0D: A8       tay                  copy the angle into y
0D0E: 29 3F    and #$3f
0D10: D0 03    bne $0d15
0D12: 4C B3 0D jmp $0db3            jmp to 0db3, one of our special cases 00,40,80,c0.
0D15: B9 00 0F lda $0f00, y         get our lookup table value
0D18: CA       dex                  decrement x (because when we do the adds, the carry bit will be set)
0D19: 86 01    stx $01              store x in $01  (multiplicand minus 1 goes in $01) 
0D1B: 4A       lsr a                shift a right
0D1C: 85 02    sta $02              store a in $02 (will shift bits in and out of $02 with ror, when done $02=low byte of result)
0D1E: A9 00    lda #$00
0D20: 90 02    bcc $0d24
0D22: 65 01    adc $01
0D24: 6A       ror a
0D25: 66 02    ror $02
0D27: 90 02    bcc $0d2b
0D29: 65 01    adc $01
0D2B: 6A       ror a
0D2C: 66 02    ror $02
0D2E: 90 02    bcc $0d32
0D30: 65 01    adc $01
0D32: 6A       ror a
0D33: 66 02    ror $02
0D35: 90 02    bcc $0d39
0D37: 65 01    adc $01
0D39: 6A       ror a
0D3A: 66 02    ror $02
0D3C: 90 02    bcc $0d40
0D3E: 65 01    adc $01
0D40: 6A       ror a
0D41: 66 02    ror $02
0D43: 90 02    bcc $0d47
0D45: 65 01    adc $01
0D47: 6A       ror a
0D48: 66 02    ror $02
0D4A: 90 02    bcc $0d4e
0D4C: 65 01    adc $01
0D4E: 6A       ror a
0D4F: 66 02    ror $02
0D51: A2 00    ldx #$00
0D53: 90 07    bcc $0d5c              no sign bit, so let's branch to d5c
0D55: 49 FF    eor #$ff               sign bit is set, so negate our result A by EOR #$FF, and ADC #$00 (carry is set)
0D57: 69 00    adc #$00
0D59: F0 01    beq $0d5c              need this branch here, because if A was 0, we don't want -0 to come back as FF00 (-256).
0D5B: CA       dex                    decrement x so x will be #$FF
0D5C: 85 22    sta $22
0D5E: 86 23    stx $23
0D60: A6 00    ldx $00
0D62: 98       tya                    Multiply by SIN value, first get the angle from the Y register
0D63: 18       clc
0D64: 69 C0    adc #$c0               add #$c0 (add 192) since sin A is cos(A-0x40)=(A+0x100-0x40), addition wraps around 0-255
0D66: A8       tay                    put our new angle (+192) back into Y
0D67: B9 00 0F lda $0f00, y           get the value from the cos table
0D6A: CA       dex
0D6B: 86 01    stx $01
0D6D: 4A       lsr a
0D6E: 85 02    sta $02
0D70: A9 00    lda #$00
0D72: 90 02    bcc $0d76
0D74: 65 01    adc $01
0D76: 6A       ror a
0D77: 66 02    ror $02
0D79: 90 02    bcc $0d7d
0D7B: 65 01    adc $01
0D7D: 6A       ror a
0D7E: 66 02    ror $02
0D80: 90 02    bcc $0d84
0D82: 65 01    adc $01
0D84: 6A       ror a
0D85: 66 02    ror $02
0D87: 90 02    bcc $0d8b
0D89: 65 01    adc $01
0D8B: 6A       ror a
0D8C: 66 02    ror $02
0D8E: 90 02    bcc $0d92
0D90: 65 01    adc $01
0D92: 6A       ror a
0D93: 66 02    ror $02
0D95: 90 02    bcc $0d99
0D97: 65 01    adc $01
0D99: 6A       ror a
0D9A: 66 02    ror $02
0D9C: 90 02    bcc $0da0
0D9E: 65 01    adc $01
0DA0: 6A       ror a
0DA1: 66 02    ror $02
0DA3: A2 00    ldx #$00
0DA5: 90 07    bcc $0dae
0DA7: 49 FF    eor #$ff
0DA9: 69 00    adc #$00
0DAB: F0 01    beq $0dae
0DAD: CA       dex
0DAE: 85 24    sta $24
0DB0: 86 25    stx $25
0DB2: 60       rts
0DB3: 98       tya             we copied the angle to the Y register before, so copy angle back to A
0DB4: D0 0D    bne $0dc3
0DB6: A2 00    ldx #$00        angle = 0 or #$00, cos = 1, sin = 0
0DB8: 86 24    stx $24
0DBA: 86 25    stx $25
0DBC: A5 00    lda $00
0DBE: 85 22    sta $22
0DC0: 86 23    stx $23
0DC2: 60       rts
0DC3: 30 0D    bmi $0dd2
0DC5: A2 00    ldx #$00        angle = 90 or #$40, cos = 0, sin = 1
0DC7: 86 22    stx $22
0DC9: 86 23    stx $23
0DCB: A5 00    lda $00
0DCD: 85 24    sta $24
0DCF: 86 25    stx $25
0DD1: 60       rts
0DD2: 29 40    and #$40
0DD4: D0 10    bne $0de6
0DD6: A2 00    ldx #$00        angle = 180 or #$80, cos = -1, sin = 0
0DD8: 86 24    stx $24
0DDA: 86 25    stx $25
0DDC: 38       sec
0DDD: 8A       txa
0DDE: E5 00    sbc $00
0DE0: 85 22    sta $22
0DE2: CA       dex
0DE3: 86 23    stx $23
0DE5: 60       rts
0DE6: A2 00    ldx #$00         angle = 270 or #$C0, cos = 0, sin = -1
0DE8: 86 22    stx $22
0DEA: 86 23    stx $23
0DEC: 38       sec
0DED: 8A       txa
0DEE: E5 00    sbc $00
0DF0: 85 24    sta $24
0DF2: CA       dex
0DF3: 86 25    stx $25
0DF5: 60       rts

Comparing the cosine table to math.cos

Let's see how closely Stellar 7's cosine table compares to math.cos().

cpu = manager:machine().devices[":maincpu"];mem = cpu.spaces["program"]

function max(a,b) if a>b then return a else return b end end 
function min(a,b) if a<b then return a else return b end end
function round(x) if x<0 then return math.floor(x-0.5) else return math.floor (x+0.5) end end

function clearpage(page) page = page or 1 for i=page*8192,page*8192+8192-1 do mem:write_u8(i,0) end end

function showpage(pg) pg = pg or 1 mem:write_u8(0xc057,0) mem:write_u8(0xc050,0) mem:write_u8(0xc052,0) mem:write_u8(0xc054+pg-1,0) end

function calcyaddr(line,page) page = page or 1 return line % 8 * 1024 + math.floor(line / 64) * 40 + math.floor((line%64) / 8) * 128 + (8192 * page) end

function plot(x,y,page) page=page or 1 x = max(0,x) x = min(x,279) y = max(0,y) y = min(y,191) mem:write_u8(calcyaddr(y,page)+math.floor(x/7),mem:read_u8(calcyaddr(y,page)+math.floor(x/7))|(1<<(x%7))) end

function draw_text(x,y,text) emu:pause() manager:machine().screens[":screen"]:draw_text(x,y,text) end
function draw_line(x,y,x2,y2,color) emu:pause() color=color or 0xffffffff manager:machine().screens[":screen"]:draw_line(x,y,x2,y2,color) end

clearpage()
sc=40 
for i=0,255 do 
cosvalue=mem:read_u8(0xf00+i) signbit=(cosvalue&0x80) cosvalue=cosvalue&0x7F 
if signbit~=0  then cosvalue=-cosvalue end 
print(i,cosvalue,math.cos(i/256*2*3.14159)*128,cosvalue-math.cos(i/256*2*3.14159)*128) 
plot (i,96+round((cosvalue-math.cos(i/256*2*3.14159)*128)*sc)) 
plot (i,96+sc) 
plot (i,96-sc) 
plot (i,96+math.floor(cosvalue/128*96)) 
plot (i,96+math.floor(math.cos(i/256*2*3.14159)*92)) end 
draw_text(0,0,"costable is higher curve\n cos() is lower curve\n  difference range is within +/- 1/128th")


-- all as one line

clearpage() sc=40 for i=0,255 do cosvalue=mem:read_u8(0xf00+i) signbit=(cosvalue&0x80) cosvalue=cosvalue&0x7F if signbit~=0  then cosvalue=-cosvalue end print(i,cosvalue,math.cos(i/256*2*3.14159)*128,cosvalue-math.cos(i/256*2*3.14)*128) plot(i,96+round((cosvalue-math.cos(i/256*2*3.14159)*128)*sc)) plot(i,96+sc) plot (i,96-sc) plot (i,96+math.floor(cosvalue/128*96)) plot (i,96+math.floor(math.cos(i/256*2*3.14159)*92)) end draw_text(0,0,"costable is higher curve\n cos() is lower curve\n  difference range is within +/- 1/128th")


-- emu:unpause() to get the draw_text and draw_lines off the screen
-- also you may need to step the debugger window to get the mame window to update

There's some interesting patterns in the difference between the cosine table and math.cos. It's never more than 1/128 or about +/- 1% difference. The horizontal lines are the range -(1/128) to +(1/128).

I wonder how this compares to Ulugh Beg's cos table.