Arnold-m68k 1.5

Amstrad CPC/CPC Plus/GX4000 emulator

Short:        Amstrad CPC/CPC Plus/GX4000 emulator
Author:       Kevin Thacker (Arnold), Amiga port by John Stringer
Uploader:     Zoopster (JCEC_1 yahoo co uk)
Type:         misc/emu
Version:      1.5
Replaces:     misc/emu/Arnold-m68k.lha
Requires:     68040 or better, AGA
Architecture: m68k-amigaos >= 3.1.0
Distribution: Aminet
Kurz:         Amstrad CPC/CPC Plus/GX4000 Emulator

Arnold for Amiga is a port of Kevin Thacker's Arnold, the Amstrad CPC
emulator, to 68k AmigaOS 3.x with AGA. It emulates the CPC 464, 664 and
6128 as well as the CPC 6128 Plus and the GX4000 console: Plus cartridges,
disks and snapshots, with sound through Paula, on PAL and NTSC displays.
Released with Kevin's blessing, under the GPL.

Requirements
------------
- AmigaOS 3.1 or later, AGA.
- A 68040 or better: PiStorm32 (Emu68), 68060 cards, or BigMig on MiSTer.
  No FPU needed.
- lowlevel.library is optional (CD32 pads).
- Fast vertical scrolling uses about 0.5 MB more chip RAM; with less
  free, Arnold falls back to the plain display (NOVSHIFT forces that).

What to expect
--------------
Arnold for Amiga targets PiStorm/Emu68-class machines. On an A1200 with
a PiStorm32 CM4, the games tested run at full speed (Sonic GX at 50 fps
without frame skip, springs included, measured: about 60% of the frame
time). On BigMig (MiSTer) games currently run below full speed; use
the BigMig preset (Arnold-060 with frame skip, on the RTG screen). Real
68060 accelerator cards have not been tested; expect games below full
speed. 68030 machines are too slow for games.

Installation
------------
Copy the Arnold drawer anywhere. Start one of the presets:
  Arnold PiStorm   68040 build, sound on, frame skip up to 3
  Arnold BigMig    68060 build, sound on, frame skip up to 3, on
                   BigMig's RTG screen
  Arnold RTG       as Arnold PiStorm, on an RTG screen with scanlines
or the program itself. HELP opens the menu (media, settings, controls).
README.txt in the drawer has the details, keys and Shell options.

The drawer includes the Plus system cartridge (BASIC 1.1, AMSDOS and
Burnin' Rubber) and the CPC 464/664/6128 system ROMs, so CPC disks and
the built-in game work at once, and Games.db (settings for known
games). Supply your own cartridge (.cpr) and disk (.dsk) images.

Features
--------
- CPC 464, 664, 6128, 6128 Plus and GX4000 models, picked in the menu.
- Plus / GX4000 cartridges (.cpr), standard and extended disks (.dsk) in
  drives A and B, snapshots (.sna).
- Save states: four slots per game (Project menu, or Left Amiga +
  F1-F4 to save, Right Amiga + F1-F4 to load). A state keeps the whole
  machine and the disks in the drives; the game goes on exactly where
  it was.
- Tapes (.cdt) with fast loading and an optional loading sound, and
  auto-start: Power ON types the load command (RUN", |TAPE) and
  presses a key at PLAY. Disk saves are written back to the .dsk (the
  original kept as .bak).
- Fast-forward: hold ` (left of 1) and the CPC runs as fast as the
  Amiga allows, without sound; the emulation is unchanged.
- PAL or NTSC (or as Workbench); on NTSC the CPC still runs at its own
  50 Hz, so games and music keep their correct speed.
- Paula sound (8-bit stereo); frame skip keeps heavy games at full speed.
- RTG screen (experimental, RTG): with an RTG board and an 8-bit mode
  (PiStorm VideoCore, uaegfx) the emulation and the menu show on an RTG
  screen, optionally with scanlines (Hard 25/50/75%, Blended light,
  normal, strong). Frames are written at the vertical blank, so there
  is no tearing. Off by default.
- Games.db: settings for known games (wide, full height, key remap,
  joy keys), found by the CRC-32 of the cartridge, disk or tape.
- Menu with pull-down options, per-game settings (for disk games too),
  keyboard map, IFF and PNG screenshots; Workbench presets with
  ToolTypes. Full height (TALL) and wide (WIDE) options, per-game key
  remap (REMAP=) with a key-map editor and presets.
- Joystick in port 2 (normal or CD32 pad, chosen in the menu) and the
  keyboard as a joystick (mode 3: X / Space are fire 1, for R-Type).
- Fixes to the Arnold core found during the port: Plus soft scroll,
  raster and DMA interrupt timing, CRTC and ASIC write timing, the sound
  chip, the Z80 overflow flag, disk image loading and more (offered
  upstream as patches).

Known issues
------------
- NTSC shows fewer lines than PAL, so games drawn to the screen edges
  lose their top and bottom; use PAL for the full picture.
- Tapes load only: no saving to tape, and only .cdt images (no .wav,
  .voc or .csw, so these are not auto-started either).

History
-------
1.5    Fast-forward: hold ` (left of 1) and the CPC runs as fast as
       the Amiga allows, shown about 10 times a second without sound,
       with a ">>" symbol at the top left. Auto-start tapes (Options
       menu, AUTOTAPE=; on by default): Power ON types RUN" on a 464,
       |TAPE and RUN" on a 664 or 6128 (f1 first on the Plus) and
       presses a key at "Press PLAY then any key". Black is no longer
       drawn in the border colour (the black outline of R-Type's
       Easter Egg logo, Copter 271). The on-screen messages now show
       on RTG screens with scanlines.
1.4    Save states: four slots per game (Project menu, or Left Amiga +
       F1-F4 to save and Right Amiga + F1-F4 to load while playing),
       with a short message on the screen. A state keeps the whole
       machine and every disk in the drives, and the game goes on
       exactly where it was. RTG frames are written at the display's
       vertical blank, so there is no tearing (on by default; RTGVBL=0
       writes them at once, as 1.3 did). The BigMig preset now uses the
       RTG screen. Slightly faster: undrawn (skipped) lines no longer
       work out their sprites.
1.3    Smoother AGA display. Only the bitplanes in use are shown, so
       chip RAM writes are faster, and the log is no longer written
       to disk every second. On a PiStorm, Sonic GX frames over 20 ms
       dropped from 15-19 to about 2 per run. Options NOBPU and
       HEARTBEAT bring back the 1.2 behaviour; CHIPBENCH times chip
       RAM writes.
1.2    RTG screen (experimental): the emulation and the menu on an
       8-bit RTG screen, with scanlines (Hard 25/50/75%, Blended
       light/normal/strong) and an Arnold RTG preset (Hard 50%). A game
       settings database (Games.db). Joy keys mode 3: X / Space are
       fire 1. HIRES screen: stale lines (changed lines not redrawn)
       fixed.
1.1    Optional tape loading sound (TAPESOUND). Fixes from a code
       review: game key maps cut off when saved, a fast-RAM leak on
       every Help/Reset, a failed ROM load, bad REMAP= values, a double
       free on close with plain screen buffers, a bad .cpr starting the
       previous game, stuck joystick keys after Help, disk write-back
       refused on volumes that shorten long names, and smaller bounds
       checks. Joy keys: key repeat ignored, a key-up is never lost; menu
       and docs say which keys are fire 1 and fire 2.
1.0    Tape (.cdt) support with fast loading. Disk write-back (the
       original kept as .bak). Wide screen option (WIDE). Key-map
       editor and presets. Pinball Dreams intro logo fixed (monitor
       line length and horizontal flywheel).
       From 0.x: every CPC model, 50 fps Sonic GX, Paula sound.
0.9    Sonic GX at full 50 fps on a PiStorm, springs included (code
       shaped for Emu68). Much cleaner sound (sound chip fixes). Pinball
       Dreams fixed (CRTC write timing) and a Full height option (TALL).
       Per-game key remap (REMAP=, remap= in prefs); disk games now get
       their own <disk>.prefs. Plus register and DMA timing closer to
       real hardware. 80-track disk images load (Pinball Dreams: Beat
       Box, Nightmare). A display left at 60 Hz by another program is
       put back to 50 Hz (PAL).
0.8    Faster vertical scrolling (the display moves the picture in a
       taller chip RAM buffer instead of redrawing it) and faster Plus
       sprites. Sonic GX on a PiStorm: the slowdown on fast vertical
       scrolls (springs) is now barely noticeable.
0.7    Much faster on full-screen scrolling games: only changed parts of
       the screen are written to chip RAM, 5 or 6 bitplanes where 8 are
       not needed, batched video emulation, table-driven Plus soft
       scroll. Sonic GX: 41 -> 49 fps on an A1200 with PiStorm32, without
       frame skip. New Arnold-030 build.
0.6    CPC 464/664/6128 and GX4000 models; Video mode (Auto/PAL/NTSC)
       and Game speed in a new Settings box and Display menu; correct
       50 Hz game and music speed on NTSC; menu fits 200 lines; screen
       surround shows the CPC border colour; no Workbench flash.
0.5.2  Plus DMA interrupt fixes: Sonic GX's Green Hill split glitch and
       its frozen special stage. The menu scrolls on NTSC displays.
0.5.1  First Aminet release.

Source and reports
------------------
Source, patches and issue tracker: https://github.com/z00p/arnold-amiga
Please report problems there with the game, your settings and your
machine.

Credits
-------
Arnold (c) Kevin Thacker, GPL-2.0. Amiga port by John Stringer, 2026.
CPCEC by CNGSoft was the accuracy reference for the Plus fixes.
The RTG screen uses the RTG display framework rtgfw (c) 2026 Zoopster,
MIT licence (LICENSE-rtgfw in the drawer).