Meine Notizen

2024-05-15

Zusammgenfassung Fefes Hackback presentation

Annahmen von Hackback

Wir werden angegriffen
- Wie definieren?
- Eher runtergekommene Infrastruktur
Wir merken es zeitnah
- Nein. Ein halbes bis fünf Jahre.
Wir können den Angreifer identifizieren
- Nein. IP-Log des gehackten Servers. Aber Quelle Quelle? Nein. NSA Quantum Insert macht IP sogar noch wertloser.
Wir können zurückschlagen
- Hacken wurde kriminalisiert
- Exploits kaufen hochspekulativ
- Exploits einmalig
- Exploits unethisch
Das verhindert weitere Angriffe
- Generell anzuzweifeln
- Hackbacked entities kopieren den Exploit...

Kurz: Humbug.

2024-04-21

Stichpunkte zu "Don't make me think"

Based on years old notes.

Core

Pro-user: "I am the Developer, I speak for the Users"
buttons look like buttons
not cluttered
appropriate naming

=> make stuff self-evident, we scan, satifice and muddle through

Design like billboards

convetion before inovation
visual hierarchy
clearly defined areas
obvious clickable/interactable
remove distractions/noise
support scanning (e.g. paragraphs)
omit (needless) words

try and find something (search vs browse)
digital/web difficulaties: no spatial scale, direction, location -> conventions
tabs are awesome

User Testing, User Testing, User Testing

1on1
early
reccomended: continious/monthly, recruit loosly, many (hidden) viewers, quiet palce
typical problems: unclear concept, missing key words, too much clutter
debriefing: collective ordered list; don't add things!

2024-04-20

Stichpunkte zu "The Design of Everyday Things"

Based on years old notes.

Core

not human error, bad design
75-95% industrial accidents "human error"

Terms/Basics

Make it discoverable & understabdable (Challenge: Modern device complexity)
Affordance (dt. Angebotscharakter): relation between object properties & agents capability. "What actions possible?"
Signifiers: Signaling component of affordance. "Where actions possible?"
Mappings: relations of elements (especially spatial)
Feedback: communication of action result (immediate, informative, etc.)
Constraints: e.g. one thing deactivates other

User perspective

user-interaction loop: user-interaction ongoing loop of execution and evaluation (e.g. 7-stages-model)
human (thought): "opportunistic", lazy, subconcious
- Kanemann Fast/Slow; Norman Declerative/Procedural
humans use stories (conceptual model) matching cause&effect
learned helplessness: self-fullfilling prophecy, own failure -> stop trying
- Thus: Don't fault users, use these hints!
- Make errors cost free

4 constraints

physical:
- physical goto
- should allow alls percived actions
- alternatives possible (e.g. key vs biometric)
- Examples: Forcing (car key), Interlocks (dead-man switch), lock-in (closing warning), lock-out (emergency door 1-way)
culture: (may change over time)
- may change with time
- may dissallow action
semantic (meaning)
logical (e.g. by exclusion)

Errors

How? Root cause analysis ! Ask 5 times why. (or more general design thinking)
- mistakes may difficult to detect, or explained away
- thus: positive & active error culture
Undelibrate: Unnatural Behaviour (e.g. pressure, interruption, multitasking,...)
Deliberate (e.g. kurzer dienstweg)

slips (=wrong action):
- action-based
- memory-lapse
- handle slips:
  - capture slips (start processes differently)
  - similar-desc. slips (controls should look different)
  - mode slips (same controls, different meaning)
mistakes (=wrong plan/goal):
- rule-based (right goal, wrong action)
- knowlege-based (misdiagnosis)
- memory-lapse
- handle mistakes
  - rule-based: help beginners
  - knowledge-based: give documentation, search, collab.
  - memory-lapse: make info/state always visible

Designing

natural mapping:
1. controls on item itself
2. Controls as close as possible
3. Controls same spatial arrangement
4. (maybe culutre diff. e.g. left/right reading/driving)
minismise for error:
- sensibility checks (telephone numerical?)
- reversability (wrong click, go back! undo!)
- make errors discoverable (use constraints e.g. conf. popup)
- actions are not errors
- support autocomplete approximation
- avoid: ambiguity, unclear model, no feedback & interruptions
- avoid: Featuritis, Matching competition, force newest tech

Design Principle

put operational knowledge in the world
use constraints (forcig, mapping etc.)
support interaction loop (discoverable, feedback, etc.)

2024-04-13

Taking a look at CSS size types

Relative

Relative to display itself:

10px

A pixel is the smallest unit on a display, that you are able to get a sharp 1px line. Thus relative to the used display. This includes images, so image-px. map to css-px, not display-px. In printing however 1px must be exactly 1/96th of an inch in all printed output. Thus px is a good unit to use, when requires alignment of text to images, or need for sharp x*1px

Relative to parent size:

10%

Relative to font size:

10em - font size

10rem - root font size

10ex - x height

Relative to viewed window:

10vw - view width

Absolute

Absolute (for printers):

10in

10cm

10pc

10mm

10pt

viewport meta tag

Now what does viewport="content="width=device-width, initial-scale=1.0" do? This is more or less legacy of old web and old small resolution mobile devices. Because there were no responsive websites early on, small screen devices would render the site based on a larger, more common desktop resolution. width=device-width sets the true width and initial-scale=1.0 zooms correctly. In the following you see 4 examples, rendered with Firefox Developer tools.

Examples:

No viewport meta tag:

Initial-width only:

initial-scale only:

Both:

2024-04-10

Stichpunkte zu "Das geheime Leben der Bäume"

This books has quite a few critics, but its a nice short read. Here some points to remember for me:

There might be a Wood Wide Web, plants communicating via biochemical signals, electrical signals, Duftstoffe, nutrial transfer.
Trees support each other in the forest via nutriant transfer.
If trees have time, they adapt and might thrive to the environment, even if its not their thought of habitat.
There are species of trees that have a kind of male/female distinction (8billiontrees.com)
Slow growing trees are long living trees.
Old trees create more biomass than younger trees. (journals.plos.org trees in tropical jungle: "In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock.")
Forests are needed to get water inland via vapor, particals for water to condense and stop eroision. (Paper)
Vibrant redness may be an insect repellant (less vibrant more attraction for insects, cause maybe weaker; no consensus whether this is true).
Laubbaeume(100ma) jünger als Nadelbaeume (170ma)
Hunters also feed animals, so to have more to hunt. This may also damage the young forest trees, as they are eaten by hungry game. (This is quite complicated and depends on the laws of a country and your opinion/position.)
I really enjoyed the Kapitel "Straßenkinder".

In the end this emphasises the need for old growth forest/Urwald, leaving the forest to itself and treating trees not just as implict. (Especially the possible late biomass increase make me more skeptical of taking trees out, while also protecting it. Same goes for hunters. Both are also driven by economic incentives) However, many opinions he has are quite out there and could be presented much more objectivly, but it is not that kind of book.

2024-04-05

Building a minimal Gameboy game

I stumbled again over the Gameboy assembler tutorials. This time I delved a little into the tutorials and wrote these notes to remember.
Links: gbdev.io/gb-asm-tutorial - gbdev.io/pandocs - rgbds.gbdev.io/docs

The minimal "game" I went for:
a falling object needs to be avoided
by the player moving left/right.
Includes: input, sprite movement, collision.

RGBDS = Rednex Game Boy Development System
Game Boy CPU has seven 8-bit GPRs: a, b, c, d, e, h, and l; of which a is accumulator; others ar paired bc, de,hl; a is technically af and can also hold 8bit, but f cannot be used alone
Flags: Z Zero flag/equal flag; N Addition/subtraction; H Half-carry; C Carry/larger/smaller
Reminder that two hex values, or rather a half-byte, is called a nibble.
Numerical prefixes: $-prefix means hexadecimal/0x, %-prefix is binary/0b
"man 7 gbz80" includes instruction references
Gameboy memory table: gbdev.io/gb-asm-tutorial/memory
Gb uses tiles of 8x8 pixels for storing graphics/the tiles (with 256 possible 8x8 tiles). A tile map (mapping of tiles) for displaying the tiles. Very good explanation at huderlem.com/demos/gameboy2bppl
Gb-Image-Converter needs http to work for me. Click in top left corner to input a 36x36 image and convert to gb code
Awesome-GBDEV list with many links to development resources.
Detailed document on Gameboy architecture, archived semis.demon.co.uk/Gameboy/Gbspec.txt
Defining Constants: DS, DB= DS 1, DW = DS 2, DL = DS 4 Reminder: de is a register. In Words: DS = Define Static (into ROM), DB= Define Byte, DW = Define Word, DL = Define Long
jp c happens when a - operand < 0; jp nc happens when a - operand >= 0; gbdev.io/gb-asm-tutorial/part1/jumps rgbds.gbdev.io/docs/gbz80.7#JP_HL

Annotated source code:

INCLUDE‘INCLUDE path’ acts as if the contents of the file at path were copy-pasted in place of the INCLUDE directive. rgbds.gbdev.io/docs "hardware.inc"hardware.inc includes many hardware definitions.github.com/gbdev/hardware.inc
 
SECTIONYou must define a SECTION. This tells the assembler what kind of information follows and, if it is code, where to put it. rgbds.gbdev.io/docs "Header", ROM0[$100]

  jpjp=jump, in this case without condition to "EntryPoint".
The header data below is addressed directly, so jump over EntryPoint

  ; Make room for the header
  dsds = define static, puts data in read-only memory (ROM). $150 - @, 0Gameboy roms needs a certain space for header information. This command tells the compiler to leave empty the space up to position $150, starting at (@) current position. gbdev.io/gb-asm-tutorial
Quoting in detail:
"It may not be obvious how this ds ends up filling that specific memory range. The 3-byte jp covers memory addresses $100, $101, and $102. (We start at $100 because that’s where the SECTION is hardcoded to be.) When RGBASM processes the ds directive, @ (which is a special symbol that evaluates to “the current address”) thus has the value $103, so it fills $150 - $103 = $4D bytes with zeros, so $103, $104, …, $14E, $14F." 

EntryPoint:This is how you declare a jump point

WaitUntilVerticalBlankStart:In short: this quasi-function checks values at position rLY=$FF44 to get to 144. Only then can we change the tiles/sprites. If we don't do this, a real gameboy may get damaged.
    ldld = load, in this case into register content of rLY a, [rLY][ ] tells us to get what is at position rLY. rLY=$FF44, y-coordinate of the gameboy LCD
    cpCompares value at a with given value (gv) 144, by subtracting the given value with the register value.
This means, if a = gv, zero flag z is 1. If a < 144, the carry flag c is 1. rgbds.gbdev.io/docs a, 144
    jpjp = jump, in this case jump back up if [rLY]<144 c, WaitUntilVerticalBlankStart

    ld [rLCDC], [LCDCF_OFF]loads LCDCF_OFF=0 into rLCDC=FF40. Defined in hardware.inc

    ; Copy the tile dataThis is an assembly function call. The parameters are loaded into the registers, then the function is called.
What happens: Loads the starting point of Tiles into de, and a counter into bc (by calculating the differenc of end-start). hl the Video-RAM to copy into. The function then loads tiles, until the end is reached.
    ld de, Tiles
    ld hl, _VRAM9000
    ld bc, TilesEnd - Tiles
    call Memcopy

    ; Copy the tileMapSame function call as above, but the mapping to the screen is loaded into _SCRN0=9800.
    ld de, Tilemap
    ld hl, _SCRN0
    ld bc, TilemapEnd - Tilemap
    call Memcopy

    ; Copy sprite tile
    ld de, Player
    ld hl, _VRAM
    ld bc, PlayerEnd - Player
    call Memcopy

    ; Copy ball tile
    ld de, Ball
    ld hl, _VRAM + $10
    ld bc, BallEnd - Ball
    call Memcopy

    ; Clean OAMRAMObject Attribute Memory (OAM) RAM is for sprites and takes 160bytes. We load 0 into all 160 bytes.More details:
Per object you get 4 bytes for x-position, y-position, tile id and "attributes". Thus we can store 40 objects. Note: the x-pos. stores is x-screen-pos. minus 8,  the y-pos. minus 16. (So the top left of the max-size sprite. More infos at   gbdev.io/gb-asm-tutorial
    ld a, 0
    ld b, 160
    ld hl, _OAMRAM
ClearOAMRAM:
    ld [hli][hli] gets the value in register hl, and increments it after using it. Alternativly you could use [hl+]. Also [hld] or [hl-] for decrementing. rgbds.gbdev.io/docs, a
    decdec = decrement -=1 b
    jp nz, ClearOAMRAM

    ; Draw objects in AMRAM
    ; Player sprite
    ld hl, _OAMRAM
    ld a, 128 + 16Put y-position in register a, in this case the onscreen position 128 + offset 16
    ld [hli], aPut y-position in the _OAMRAM and move to the x-position.
    ld a,  16 + 8x=position 16 + offset 8
    ld [hli], a
    ld a, 0
    ld [hli], aWe are at the third position. Now set the tile for this sprite. In this case 0, which is the first tile and just an all black tile.
    ld [hli], aNo attributes. Set 0 as well.
    ; Ball spriteSame goes for the only other sprite, the ball.
    ld a, 0
    ld [hli], a
    ld a, 32 + 8
    ld [hli], a
    ld a, 1
    ld [hli], a
    ld a, 0
    ld [hli], a

    ; Turn the LCD on
    ld a, LCDCF_ON | LCDCF_BGON | LCDCF_OBJONAll variables defined in hardware.inc that are bitwise or'ed to activate LCD, background tiles and object sprites.
    ld [rLCDC], a

    ; During the first (blank) frame, initialize display registersHere notes from the hardware.inc:
; --
; -- BGP ($FF47)
; -- BG Palette Data (W)
; --
; -- Bit 7-6 - Intensity for %11
; -- Bit 5-4 - Intensity for %10
; -- Bit 3-2 - Intensity for %01
; -- Bit 1-0 - Intensity for %00
; --
DEF rBGP EQU $FF47

; --
; -- OBP0 ($FF48)
; -- Object Palette 0 Data (W)
; --
; -- See BGP for info
; --
DEF rOBP0 EQU $FF48
    ld a, %11100100
    ld [rBGP], a
    ; initialize one of the object palettes, rOBP0
    ld a, %11100100
    ld [rOBP0], a

    ; Initialize global variables
    ld a, 0
    ld [wCurKeys], a
    ld [wNewKeys], a

Main:Booting of the rom everything above is executed once, after that, we are in the loop below. First we let the current vBlank finish and wait for the next vBlank.
    ld a, [rLY]
    cp 144
    jp ncjp nc = jump no carry, jump back if rLY >= 144, Main
WaitUntilVerticalBlankStart2:
    ld a, [rLY]
    cp 144
    jp cjump carry, jump if rLY < 144, WaitUntilVerticalBlankStart2:

    ; move bullet down
    ;cp a, b sets C if a < b, and clears it if a >= b.
MoveBall:    
    ld a, 2
    ld h, a
    ld a, [_OAMRAM + 4]
    add a, h
    ld b, a
    ld a, 160
    cp a, b 
    jp c, MoveBallEnd
    ld a, b
    ld [_OAMRAM + 4], a

    ;check jump to top
    ld a, [_OAMRAM + 4]
    cp a, 159
    jp c, MoveBallEnd
    ld a, 0
    ld [_OAMRAM + 4], a
    ;; add random x position
NewBallY:
    call rand
    ld a, 161
    cp a, b
    jp c, NewBallY
    ld a, b
    ld [_OAMRAM + 5], a
MoveBallEnd:

CheckCollision:
    ; First, check if the ball is low enough to hit player.
    ;get y of player and enemy
    ld a, [_OAMRAM]
    ld b, a
    ld a, [_OAMRAM + 4]
    cp a, b
    ; If the ball isn't at the same Y position as the paddle, it can't bounce.
    jp nz, CheckCollisionEnd 

    ; Now let's compare the X positions of the objects to see if they're touching.
    ld a, [_OAMRAM + 5] ; enemy X position.
    ;right border of player, add this width to enemy
    add a, 8
    ld b, a
    ld a, [_OAMRAM + 1] ; player X position.
    ;if enemy x > player x, else End
    cp a, b
    jp nc, CheckCollisionEnd

    add a, 16 ; get player, but also added 8 for enemy right edge prev.
    ;if enemy x < player x, else End
    cp a, b
    jp c, CheckCollisionEnd

    ; player hitIf player is hit, just move him left out of the screen. He can come back by moving right.
    ld a, 0
    ld [_OAMRAM + 1], a
CheckCollisionEnd:

    ; Check the current keys every frame and move left or right.
    call UpdateKeys
    ; First, check if the left button is pressed.
CheckLeft:
    ld a, [wCurKeys]
    and a, PADF_LEFT
    jp z, CheckRight
Left:
    ; Move the paddle one pixel to the left.
    ld a, [_OAMRAM + 1]
    dec a
    ; If we've already hit the edge of the playfield, don't move.
    cp a, 7
    jp z, Main
    ld [_OAMRAM + 1], a
    jp Main

; Then check the right button.
CheckRight:
    ld a, [wCurKeys]
    and a, PADF_RIGHT
    jp z, Main
Right:
    ; Move the paddle one pixel to the right.
    ld a, [_OAMRAM + 1]
    inc a
    ; If we've already hit the edge of the playfield, don't move.
    cp a, 161
    jp z, Main
    ld [_OAMRAM + 1], a
    jp Main

; Copy bytes from one area to another.
; @param de: Source
; @param hl: Destination
; @param bc: Length
Memcopy:The lines above are just comments, but as writing a function in Assembler (asm) is hard to understand at a glance, such comments are recommended.
    ld a, [de]
    ld [hli], a
    inc de
    dec bc
    ld a, b
    ;; Or checks if length is still left, by bitwise-or of bc
    or a, c
    jp nz, Memcopy
    retret = return, returns to the place where the function is called. Can also take a condition. https://rgbds.gbdev.io/docs/v0.6.1/gbz80.7#RET_cc

UpdateKeys:This was not explained in the tutorial, and I won't dive into it myself, as I am not ver knowledgeable in asm.
  ; Poll half the controller
  ld a, P1F_GET_BTN
  call .onenibble
  ld b, a ; B7-4 = 1; B3-0 = unpressed buttons

  ; Poll the other half
  ld a, P1F_GET_DPAD
  call .onenibble
  swap a ; A3-0 = unpressed directions; A7-4 = 1
  xor a, b ; A = pressed buttons + directions
  ld b, a ; B = pressed buttons + directions

  ; And release the controller
  ld a, P1F_GET_NONE
  ldh [rP1], a

  ; Combine with previous wCurKeys to make wNewKeys
  ld a, [wCurKeys]
  xor a, b ; A = keys that changed state
  and a, b ; A = keys that changed to pressed
  ld [wNewKeys], a
  ld a, b
  ld [wCurKeys], a
  ret

.onenibble
  ldh [rP1], a ; switch the key matrix
  call .knownret ; burn 10 cycles calling a known ret
  ldh a, [rP1] ; ignore value while waiting for the key matrix to settle
  ldh a, [rP1]
  ldh a, [rP1] ; this read counts
  or a, $F0 ; A7-4 = 1; A3-0 = unpressed keys
.knownret
  ret

;tiles we can select from in the mapping
;; https://www.huderlem.com/demos/gameboy2bpp.html
;; .33333.. -> 01111100 -> $7C
;;             01111100 -> $7C
;; Three tiles: black, white, gray
Tiles:
    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF, $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
    DB $00,$00,$00,$00,$00,$00,$00,$00, $00,$00,$00,$00,$00,$00,$00,$00
    DB $FF,$00,$FF,$00,$FF,$00,$FF,$00, $FF,$00,$FF,$00,$FF,$00,$FF,$00
TilesEnd:

;maps the tiles to the screen/background, all white
Tilemap:
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
    db $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, $01, 0,0,0,0,0,0,0,0,0,0,0,0
TilemapEnd:


;; Player just a black rectangle
Player:
    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
PlayerEnd:

;; can also set it with values between 0 and 3
;; this is based on hardware.inc, symbols can be changed
Ball:
    dw `00000000
    dw `00033000
    dw `00333300
    dw `03333330
    dw `03333330
    dw `00333300
    dw `00033000
    dw `00000000
BallEnd:

;; declaring variables
SECTION "Input Variables", WRAM0
wCurKeys: db
wNewKeys: db

; RANDOM NUMBER GENERATORI just copied this from github.com/pinobatch to get a random x variable for the falling ball.
SECTION "MathVariables", WRAM0
randstate:: ds 4

SECTION "Math", ROM0

;; From: https://github.com/pinobatch/libbet/blob/master/src/rand.z80#L34-L54
; Generates a pseudorandom 16-bit integer in BC
; using the LCG formula from cc65 rand():
; x[i + 1] = x[i] * 0x01010101 + 0xB3B3B3B3
; @return A=B=state bits 31-24 (which have the best entropy),
; C=state bits 23-16, HL trashed
rand::
  ; Add 0xB3 then multiply by 0x01010101
  ld hl, randstate+0
  ld a, [hl]
  add a, $B3
  ld [hl+], a
  adc a, [hl]
  ld [hl+], a
  adc a, [hl]
  ld [hl+], a
  ld c, a
  adc a, [hl]
  ld [hl], a
  ld b, a
  ret

Further points:

The OAMRAM doesnt have attributes, more like 16 flags, depending on how you use it. Here prenamed variables in WRAM0 are used

How to build the rom:

$ rgbasm -o hello-world.o hello-world.asm #create machine code (-o = output file)
$ rgblink -o hello-world.gb hello-world.o #links code with libs
$ rgbfix -v -p 0xFF hello-world.gb #adds final rom header data; -v adds gb license; pads the rom to valid size (idk more)

Create "symbols" for debuggung: rgblink -n main.sym main.o

2024-04-01

jar/AppImage as Ubuntu Desktop-App

This is a note to help me, when I want to add a .jar or .appimage to my Desktop and call it like normally installed .deb packages:

Create a file example.desktop with the following content:

                [Desktop Entry]
                Name=Example
                Comment=The application does example
                Exec=/home/username/example/example.appimage
                Icon=/home/username/example/example.png
                Type=Application
                Terminal=false

Then call desktop-file-validate and desktop-file-install on this file. Now you find this app in the startup menu.

If you want to associate such an app with a file ending you need to edit ~/.local/share/applications/mimeapps.list (at least in Ubuntu) and add a line to the file. Use the existing associations as example.

If you want to call this program via terminal, a simple alias should suffice. Use the ~/.bash_profile or /etc/profile and add alias example="/home/username/example/example.appimage".

Interesting Words in Japanese

While learning any language you always find interesting words, that don't have a translation or have a interesting historical backround:

バタ臭い, Battakusai,　smelling of butter or more generally Western-influenced;
The Japanese used this term after WW2, when the USA gave the Japanese a template of a consitution (which "smelled like butter"). The Japanese then used the consitution as is, apparently because of the language barrier. (Note: The term itself predates this use)
Source: This was a story from a Japanese teacher at Tohoku Universtity. I can only find a Japanese source: 「。。。新憲法ではバタ臭いような表現が多いのです。。。」 which translates to something like "the expression 'new constituion reeks of butter' was used often". (Didn't read everything, don't know the page, little shady because nikkey != nikkei)
恥の文化, haji no bunka, culture of shame;
罪の文化; tsumi no bunka; culture of blame;
When studying in Japan I also talked with my friends about Japanese vs German culture. There I learned the japanese distiction between a culture of shame and a culture of blame, especially in regards to the WW2 "Aufarbeitung".
円本, enpon, Yen-books;
Reading the manga コミック昭和史/Comic Showa　I learned that in 1926 someone created cheap books, that cost just one Yen, were thus called and were a symbol of the growing middle class and education of the poeple. (Also 円タク entaku yen-taxi, same for Taxis, very short-lived)

Stichpunkte zu "Scount Mindset"

Here some points to remember for me:

"Can I believe it?" vs. "must I believe it?"
Objectivity/Knowledge != Scout, but self-change/empathy
Accept and quantify uncertainty/odds/chances
Honest coping: Make a plan and accept problems, see silver
linings; Things could be worse
Learn to change/update your thoughts, lean into confusion as
targets to map
Your communities shape your identity

Ancient Egpytian "Appeal to the living"

Hyroglyphs that translate to: As you love to live and hate to die.

Egyptian Middle Kingdom common Tombstone engraving, and excerpt from
the "Book of the Dead", called "appeal to the living" and part of it conatins:
As you love to live and hate to die.
source: @DigItWithRaven

The Rime of the Ancient Mariner & The Wanderer

After listening to Tokiens reciting of The Ride of the Rohirim, I was looking more into the Rohirim and stumbled over the poem The Wanderer in this article.
Additionally somehow I found the more modern poem Ancient Mariner, which felt similar, including the great interpretation of Iron Maiden.

Hominin & Culture timeline

Two HackerNews comments have this great little list of the human culture timeline and hominin timeline in general:

7-6 million years ago: Possible divergence of the lineage leading to humans from the lineage leading to chimpanzees and bonobos (our closest living relatives).
Ardipithecus kadabba (~5.8-5.2 million years ago)
Ardipithecus ramidus (~4.4 million years ago)
Australopithecus anamensis (~4.2-3.9 million years ago)
Australopithecus afarensis (Lucy) (~3.9-2.9 million years ago)
Kenyanthropus platyops (~3.5 million years ago)
Australopithecus africanus (~3.3-2.1 million years ago)
Paranthropus aethiopicus (~2.7-2.3 million years ago)
Australopithecus garhi (~2.5 million years ago)
Paranthropus robustus (~2-1.2 million years ago)
Homo habilis (~2.1-1.5 million years ago)
Homo rudolfensis (~1.9 million years ago)
Homo ergaster/Homo erectus (~1.9 million years ago - ~143,000 years ago)
Paranthropus boisei (~1.7-1.1 million years ago)
Homo heidelbergensis (~700,000-300,000 years ago)
Homo naledi (~335,000-236,000 years ago)
Homo neanderthalensis (Neanderthals) (~400,000-40,000 years ago)
Denisovans (around 300,000-50,000 years ago)
Homo sapiens (modern humans) (~300,000 years ago to present)

Oldowan industry - simple flaked stone tools (~2.9-1.7 million years ago)
Acheulean industry - advanced tools like hand axes (~1.7 million - ~160,000 years ago)
Archaic humans in Southeast Asian islands like Indonesia (~1.8-1 million years ago, dating is a bit uncertain on this one)
First control of fire (~1 million - ~700,000 years ago)
First archaic humans living in colder climates like Atapuerca, Spain (~800,000 years ago)
First wooden spears denoting a change in hunting tech (~400,000 years ago)
Widespread control of fire (~400,000 years ago)
==> First homo sapiens <== (~300,000 years ago)
First neanderthals arrive in Europe (~230,000-150,000 years ago)
First use of ochre pigment for symbolic purposes (~190,000 years ago)
Body lice genetically diverge from head lice due to clothing (~170,000 years ago)
Mousterian industry - points, scrapers, denticulates, notches, and awls (~300,000-40,000 years ago)
First time eating seafood at Pinnacle Point (~150,000 years ago)
Humans start collecting and using shell beads (~130,000 years ago)
First heat treated material - silcrete (~110,000 years ago)
First compound adhesive leads to tar-hafted tools (~100,000 years ago)
First bed (~77,000 years ago)
First bow and arrow in Sibudu (~72,000–60,000 years ago)
Arrival in Australia (and thus first boat?) (~70,000-65,000 years ago)
First musical instrument (flute) (~60,000 years ago)
First burial ritual at Shanidar Cave (~60,000 years ago but controversial)
First sewing needle (~45,000 years ago)
Aurignacian industry - true homo sapien tools like microlithics, blades, projectile points, pressure flaking, split-base bone points (~43,000-26,000 years ago)
Gravettian industry - Bow and arrow, harpoons, and darts come into their own (~33,000-22,000 years ago)
Solutrean & Magdalenian industry - flint tools, cave art, etc. (~22,000-12,000 years ago)

Zusammgenfassung Fefes Hackback presentation

Annahmen von Hackback

Stichpunkte zu "Don't make me think"

Core

Design like billboards

Navigation

User Testing, User Testing, User Testing

Stichpunkte zu "The Design of Everyday Things"

Core

Terms/Basics

User perspective

4 constraints

Errors

Designing

Design Principle

Taking a look at CSS size types

Relative

Relative to display itself:

Relative to parent size:

Relative to font size:

Relative to viewed window:

Absolute

Absolute (for printers):

viewport meta tag

Examples:

No viewport meta tag:

Initial-width only:

initial-scale only:

Both:

Stichpunkte zu "Das geheime Leben der Bäume"

Building a minimal Gameboy game

Annotated source code:

jar/AppImage as Ubuntu Desktop-App

Interesting Words in Japanese

Stichpunkte zu "Scount Mindset"

Ancient Egpytian "Appeal to the living"

The Rime of the Ancient Mariner & The Wanderer

Hominin & Culture timeline