8bitworkshop/doc/notes.txt

TODO:

- NaN in cycle count for macros
- debugging of scan line overflow
- confuse code/data in listing
- show memory locations hovering over lines
- don't check against ROM signatures
- DASM
  - macro forward refs
  - labels start with . omit timing info (isCode)
  - spaces in filename don't parse code listing (DASM, maybe more)
- asm: support macro expansion
- multiple breakpoints, expression breakpoints
- watchpoints
- step over (line, instruction)
- slowdown beam for all platforms?
- show errors in list (maybe window list?)
  - click to go to error
  - what if error in include file you can't edit b/c it never appears?
- online help
- show self-modifying code insns left of editor
- update Javatari version? (and others?)
- sound mute?
- $error updates source editor
- online tools for music etc
- text log debugging script
- intro/help text for each platform
- vscode/atom extension?
- click to break on raster position
- restructure src/ folders
- debug bankswitching for funky formats
- 'undefined' for bitmap replacer
- requestInterrupt needs to be disabled after breakpoint?
- C/asm source formatter
- allow download of JSASM output
- update bootstrap to 4.0
- batariBasic: proper line numbers, debugging
- builds:
  - compiler flags for final ROM build
  - workermain: split build functions, better msg types
  - what if >1 file with same name? (local/nonlocal/directory)
  - what if .c and .s names collide?
  - maybe put stuff in examples/ dir?
  - error msg when #link doesn't work
  - warning when ROM too big
  - detect "libcv.h" and include library automagically?
- sdcc:
  - can't link asm files before c files (e.g. acheader.s must be last)
  - figure out area names ordering
  - debug inline asm
- live coding URL
- resize memory browser, other windows when vertical div resize
- markdown, verilog: can't share
- https://www.crowdsupply.com/tinyfpga/tinyfpga-bx
- stego shareable images (http://pico-8.wikia.com/wiki/P8PNGFileFormat)
- https://makecode.com/language?
- open ROM from URL?
- game starts even if switched away before first load
- put globals into view/controller objects
- autostart audio
  - chrome: https://github.com/processing/p5.js-sound/issues/249
  - firefox: https://support.mozilla.org/en-US/kb/block-autoplay
- touch support
- better undo/diff for mistakes?
- ide bug/feature visualizer for sponsors
- global undo/redo at checkpoints (when rom changes)
- landscape mode for arcade ports
- symmetric load/save state types (like in Machine)
- pixel editor
  - persist palette/tilemap selections
  - more tools for editing
  - map editor
  - arbitrary nametable editing
  - metasprites
  - throw errors when bad/no refs
  - per-View keyboard shortcuts
  - parse labels
  - parse .incbin directives?
  - can't replace in hex directives
  - should maybe use same single-canvas editor for map + char editor
  - undo doesn't refresh editor
  - editing sometimes messes up cursor movement (CURBS)
- crt0.s compiled each time?
- debug highlight doesn't go away when debugging -> running
  - show breakpoint of PC or highest address on stack
  - can we highlight line instead of select?
- profiler
  - profiler restarts emulator when paused
  - running profiler while replaying? grand unified replay?
  - click on profiler to step to position
    - breakpoints stop profiler from running
  - single-screen profiler
  - hide labels that aren't available, like BIOS addrs
  - show interrupts, other events
  - sometimes interleaves two different PCs? like two profilers running simultaneously?
    - ah, symbols persist across builds
- Verilog
  - larger scope range, better scrolling
  - make scope data wrap around range
  - remove FPS and play controls when Verilog scope paused
  - when paused scope doesn't work
  - Safari: scope doesn't show while CRT in use (sometimes Firefox too)
  - verilog debugging/reloading makes it slow
  - why loadState() on verilog kill perf?
  - quantify verilog "graph iterations"
  - toolbar overlaps scope
  - CPU debugging
  - use $readmem for inline asm programs?
  - can't add control instructions b/c of split
  - bad error msg if >2 moduels and top module doesn't match filename
  - separate Scope View
  - Audio doesn't work if clock != default
- single-stepping vector games makes screen fade
- break on stack overflow, illegal op, bad access, BRK, etc
  - show in scope instead?
- nes
  - replay doesn't work for nes (force background tile redraw, sprites
    messed up)
  - nes debug view toolbar
  - support NES_HEADER_16K?
  - NES crt should mark raster pos when debugging
  - OAMDMA in profiler? (haltCycles)
  - typed arrays don't serialize?
- JSNES
  - doesn't support hiding >8 sprites
  - doesn't do sprite zero test right
  - doesn't do clip right
  - doesn't do b/w tint
- vcs
  - sometimes still plays when paused on FF
  - vcs: INPTx needs to be added to control state
  - vcs: break on # of lines changed (maybe using getRasterPosition?)
  - chrome looks blurry on vcs
  - VCS asm game library
  - VCS skips step on lsr/lsr after run to line
  - better VCS single stepping, maybe also listings
  - upgrade to 4.1 for Supercharger format
- upload multiple files/zip file to subdirectory
  - allow "include graphics.asm" instead of "include project/graphics.asm"
- convert more stuff to Promises
- don't have to include firebase always?
  - squelch error msgs? 
  - test offline? (if window.firebase)
- Github
  - platform_id/repo.platform mismatch (can't leave repository)
  - handle overwrite logic
  - what to do about included files?
  - can published files retain path?
  - what if import interrupted and partial files?
  - CORS for some blobs?
  - don't import useless files
  - support projects with subdirectories, file list?
  - switching platform of a repo?
  - make sure to flatten subdirs
  - re-publish repo (bug: doesn't put all files in local repo after publishing)
  - allow text/binary change
  - importing from subtree commits to root anyway
  - publishing Markdown file loads default file? 
  - better text/binary detection (e.g. 0xa9 copyright)
  - going into repo chooses wrong file if republished with different main
- keyboard shortcuts
  - ctrl+alt+l on ubuntu locks screen
  - alt-D doesn't work anymore
  - facade/kbd shortcuts for emulators, focus
  - maybe eat key events? ("'" messes things up)
- cookie
  - list of stuff for policy
  - popup
- convert binary to hex stmts
- "suggestions" (vblank overrun, variable # scanlines, etc)
- SMS
  - can't step back twice?
  - compiler bug in chase
- "shared" in URL doesn't work, leave in URL? (also importURL)
- 6502
  - KIL stops debugger
- TypeError: null is not an object (evaluating 'n.destination')
  https://8bitworkshop.com/v3.4.1/javatari.js/release/javatari/javatari.js
  (32:443651)	Safari	12.1.2
- Safari: doesn't send good exception reasons ("undefined")
  - probably XMLHttpRequest.timeout (https://github.com/getsentry/sentry-javascript/issues/2210)
- C64
  - disk image support
  - https://github.com/cc65/cc65/issues/946
  - player 2 joystick and keyboard conflict
  - problems with cgetc()

- upgrade to ES2020?
  - https://github.com/microsoft/TypeScript/issues/16577
  - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
  - need Edge 79+
  - no import in workers
  - copy to gen/ directory (allowJs is weird)
- ca65 line numbers are not aligned with source code
  - segments not read properly
- Debug Browser
  - more stuff like 7800 display lists
  - don't include start/end line on platforms w/o raster timing
- memory map shows subroutine symbol even after RTS
- BIOS symbols
- show current tool for file



WEB WORKER FORMAT

{code,platform,tool,dependencies}
{preload}

new:

{updates,buildsteps}
[{filepath,platform,tool}]

implicit rules
- push/shift build steps
- preprocessor, compile, assemble, link
- access to intermediate files

only build files that have changed

build options


BUILD PROJECT

local/foo.project/*.*
build all files in project
send update for dependencies at startup (single file version)
should be able to change file w/o reloading (Not platform tho)

pulldown selects file in project, or goes back to parent
gotta preserve editor windows for each one - window list
make source/disasm window visible when debugging
gutter info/errors in all files



UI REFACTOR

editor
debugger
disasm view
memory
profile
errors

separate into files

window methods:
- set
- mode
- get
- changes
- cursorActivity (inspect)
- gutters (setCompileOutput)
- current line / gutter marker (setCurrentLine / clearCurrentLine)
- source map
- global symbols
- pixel editor / find comment (openBitmapEditorAtCursor)
- update debug window (200 ms)
- inspect variable

file store mirrors that on worker

worker result:
{
	output:<rom>
	sources:{
		<path>:{lines, asmlines, listing}
	}
}

add file to errors

http://www.playvectrex.com/designit/chrissalo/vectordisplay.htm
http://oldies.malban.de/secondvectrex/index.htm


PIXEL EDITOR

everything is an editor
back/forward propogation
encoded <-> raw + spec + palette(s) <-> full tilemap <-> selected tile/sprite/metasprite
need references
panes: source code, metadata tree, graphics panes
decoded info:
- CHR tiles
- palettes
- maps/rooms
- metasprites
- metatiles
- sprite data (williams etc)
store in intermediate single file or embed in C/ASM?
we'd then have to generate C/ASM probably automatically
intermediate file could still be edited
switch between hex/graphic editor? (palettes should edit via hex)
final display types: number, color, sprite, etc
CHR editor has palette selector, obj selector
individual objects in single file or multiple files?
RLE compression

Types
- byte
- RGBA color
- structured object
  - metasprite
  - metatile
  - level actor
- bitmap
- array of stuff, array can have a shape (width,height) like numpy
Mappers can refer to multiple objs
Slice (window) of array for selections

AssetEditorView
- scan files for assets
- build hierarchical view of assets
- expand/collapse
- create editor upon expansion
- double-click to source file

Assets come from:
- chr files
- bitmap data in files
- structured data (palette, sprites, metasprites, levels, etc)
- think about new comment format, platform-specific types

Programmatic Asset Language
- load PNG, draw image, or generate bitmap font
- split into images
- paletteize
- fit into tileset/spriteset
  - NES: 8x8 or 8x16 tiles
  - 7800: 256xN slice
  - VCS: 24xN playfield, 8xN sprite, 32xN big sprite
- generate data file (asm/c/bin)
- generate char mapping
- tile generator (makechr-like)
- metasprites too
- RLE compression
- check constraints


---

Github Support

Import
Export
Login
Pull
Push

Git metadata kept in local storage

Converting from NESASM to DASM
- asl a -> asl
- subroutine keyword on labels
- [zp],y to (zp),y
- LOW(x) and HIGH(x) to <() and >()
- .db to .byte, .dw to .word
- use NES_HEADER macros
- no .bank

Cross platform NES/SMS/GG library
- use CHR RAM
  - create flipped tiles/sprites
  - create alternate palette tiles
- metatiles
- cross platform music/sound
- scrolling
  - row/column mask
  - no nametable mirroring in SMS
  - 256x240 vs 256x192

Emulator Lib
- move getPresets() (into presets/ dir?)
- CPU interface
  - execCycle(), execInsn()
  - fix/unfix PC
  - interrupt
- generic raster scanline platform
- PlatformRunner
  - handles rewind, intra-frame breakpoint, debugging
  - profiling log, exec/read/write/intr (for each bus?)
- expose video, audio, controller interfaces
- new debugging info
- memory map interface
- "About" metadata
- auto load/save state?
- handle legacy
  - VCS
  - NES
  - MAME
- MAME
  - debugging?
  - kbd instructions don't work
  

Markdown (showdown) interface
- add code patches to files
- cursor shows current state/errors (must map markdown->src lines)
- show preview emulator at each step (play button? run when viewed?)


DOCUMENTATION

memory map
BIOS routines
cc65 standard libs
cc65 headers
example headers (presets/*/*.h)
libcv headers (src/worker/lib)
ASM includes


NETPLAY

runs alongside of emulator, doesn't modify controls (just state)
when controls change: player sends control inputs + frame#
add latency so clients more often are in sync
if miss latency window, client syncs state (moves forward a few frames?)
state checksum?
socket.io


X86

https://github.com/freebasic/fbc
GW-BASIC
http://www.grifo.com/SOFT/Pacific/uk_pacific.html
http://www.cpm.z80.de/small_c.html
https://github.com/open-watcom
Free Pascal
https://bellard.org/tcc/
https://wiki.osdev.org/Smaller_C
https://yasm.tortall.net/
https://wiki.osdev.org/Tool_Comparison


COMPONENT EMULATION

Emulate discrete chips
- verilog
- js
- wasm? (overhead?)
Block diagram level
Buses
Insn/cycle timing
Pos/neg clock edge
Timers
Polling vs. callbacks (https://github.com/floooh/chips)
- callbacks might only affect devices internally, until next cycle
CRT simulator
Move leaf nodes to workers (sound chips)
CPU opcode-step switch: https://floooh.github.io/2019/12/13/cycle-stepped-6502.html
- macros are cool!
Inspect bus edges and internal state

type Bits<N> = number;
interface Clocked { }
interface BusListener<N> {
    recv(value : Bits<N>) : void;
}
class Bus<N> {
    listeners : BusListener<N>;
    send(value : Bits<N>) : void {
    }
}
function bus(bits : number) {
    return function(
      target: any,
      propertyKey: string,
      descriptor: PropertyDescriptor
    ) {
      //descriptor.configurable = value;
    };
}
class M6502_T {
    IR : Bits<16>;        /* internal instruction register */
    addr : Bus<16>;
    data : Bus<8>;

    @bus(16) address : Bus<16>;
}

Optimizations
- ordered/delayed assignments
- skip unused exprs
- opcode -> fn table
- bus protocols -> functions
- state -> lookup tables or switch statements
- vec[] -> bitmask
- multiclock execution?



STATE REWIND

in Platform:

  advance?(novideo? : boolean) : number;
  advanceFrameClock?(trap:DebugCondition, step:number) : number;

in devices:

    advanceFrame(trap:TrapCondition) : number;
    advanceClock() : void;
    advanceInsn() : number;

Should call trap() every cycle or insn of frame, or exit when returns true?