[ATARI] Altirra x86 i x64 4.40 test 23 02/11/2025

Warhawk (1986, Firebird)

Altirra x86/64 4.40 test 23 2/11/2025

changes:

• nw

features added:

• nw

bugs fixes:

• VBXE: Fixed hires artifacts when using attribute map with 1.26 core and extended color, or hires switching at the borders.
• VBXE: Fixed bugs with attribute map horizontal scrolling.

author's comment:

• Firmware manager now shows a "no firmware" entry in all-types view for firmware types that have no firmware.
• Added cvars for 1020 plotter pen colors (devices.1020.pen0-3).
• Fixed several bugs with VBXE attribute map hires bitmap: fixed artifacts at left border when scrolling, fixed scrolling addressing, fixed luma LSB adjustment being applied to the hires bitmap, and emulated hscroll >= cell width.

Altirra x86/64 4.40 test 22 9/10/2025

WarGames (1983,WarGames)

changes:

• nw

features added:

• nw

bugs fixes:

• Recorder: Fixed memory leak when using MediaFoundation-based formats.

author's comment:

• Fix memory leak when using MediaFoundation-based video recording (WMV/MP4).

Altirra x86/64 4.40 test 21 26/09/2025

changes:

• nw

features added:

• Recorder: Added support for recording and playback of stereo SAP type R.
• Recorder: Added VGM recording and playback support.

bugs fixes:

• Cartridge: Improved emulation of SpartaDOS X pass-through cartridge port.
• Devices: Fixed SIDE 3 not being switchable from a controlled cartridge port.

author's comment:

• Alt+key menu shortcuts now work in the Performance Analyzer.
• Added stereo SAP type R recording support.
• Added VGM recording/playback support (POKEY streams only).
• Fixed regression with Rapidus running at 40MHz. It is now back at 20MHz and emulation for the experimental 40MHz option is controlled by advanced cvar.
• CPU speed options no longer show as enabled while Rapidus is active.
• Fixed SIDE 3 not responding to being disabled by the upstream cartridge port.
• Fixed bugs with SpartaDOS X pass-through port.

Altirra x86/64 4.40 test 20 15/09/2025

changes:

• nw

features added:

• Recorder: Added option to pause/resume video recording.

bugs fixes:

• Recorder: Fixed bitrate not being adjustable for H.264+AAC encoding.

author's comment:

• Added pause/resume for recordings.
• Refactored ZMBV encoder, added ARM64 optimizations, and fixed some minor bugs in the resampler.
• Fixed bitrate not being adjustable with H.264+AAC encoding.
• Fixed a regression in 4.40-test with errors writing the last sector on a disk.
• Minor optimizations to performance trace load/save.

Altirra x86/64 4.40 test 19 2/09/2025

changes:

• nw

features added:

• Cartridge: MaxFlash 1Mbit flash type is now selectable, including recent SST39SF010-based cartridges.
• Devices: Added Speedy XF disk drive.
• HDevice: Added support for MyDOS XIO 34 (Make Directory) and using XIO 33 (Delete) on directories.

bugs fixes:

• Devices: Fixed some coprocessors losing cycles when single stepping.
  
• HDevice: Current directory is now cleared on reset.
• HDevice: Long file name encoding/truncation now works for directories.
• HDevice: Fixed relative paths being parsed with the wrong unit's current working directory.
• Simulator: Loading a program with Open Image no longer forces a cold reset.

author's comment:

• Flash chip type is now selectable for Maxflash 1Mbit cartridges.
• H: device fixes: current directory is now cleared on reset, fixed LFN translation of intermediate subdirectories, implemented XIO 33 behavior for directories, fixed chdir to root, fixed cwds getting mixed up between H: device units.
• Open Image on a program no longer forces a cold reset.
• Added Speedy XF full drive emulation.
• Fixed cycle counting error when single stepping 6502-based coprocessors.

The Speedy XF is an interesting drive mod -- it is essentially an XF551 with almost everything but the drive mechanism gutted and replaced with Speedy 1050 innards, including replacing the 8048 MCU with a 1MHz 65C02 + RIOT + RAM. It's fairly overspecced with 32K of ROM/RAM, only 24K/16K of which is usable. The mod goes so far as to buffer the data bus to intercept and modify status register reads from the 1772 FDC to mimic the Not Ready bit from the 1050's 279x.
Track buffering is supported by the Speedy XF, and like the Speedy 1050, it has the unusual behavior of auto-disabling track buffering and switching to a more 1050 compatible mode when booting certain types of disks. This includes slowing down the track step rate. The Speedy XF supports a track display, which displays SL when this transition happens. Booting the computer without a disk in the drive will auto-load a utility program allowing reconfiguring the drive and running DOS and copy utilities. This is fairly useful except that the drive has no NVRAM, so in emulation you have to be very careful not to reset the drive after changing settings.
Oddly, despite being based on an XF551, the Speedy XF doesn't use the same side 2 logical to physical sector mapping that the XF551 does. The XF551 maps both tracks and sectors in reverse order on side 2, but the Speedy XF maps reverse tracks with forward sectors, an unusual mapping previously only seen with the 1450XLD parallel disk drive.
The drive's extended commands and basic memory map are documented in the original manual and there is also a schematic by Guus Assmann, but much of the address decoding is hidden within two GALs that AFAICT have not been decoded. The main omission that I had to guess at is an undocumented control latch at $4004 that controls, among other things, the drive mechanism side select. 

Altirra x86/64 4.40 test 18 28/08/2025

Feud Legend (mod. 2025)" />

Feud Legend (mod. 2025)

changes:

• nw

features added:

• Command Line: Specifying more than one image will now stack media slots in order.
• Input: Added paddle input emulation.

bugs fixes:

• Input: Fixed regression with Keyboard Controller not reading properly in fast pot scan mode.
• Input: POT4-7 inputs are now grounded properly on XL/XE machines.
• POKEY: Improved accuracy of pot scan.
• Simulator: Fixed booting a new image sometimes not cancelling a program load in progress.

author's comment:

Altirra x86/64 4.40 test 17 10/08/2025

changes:

• nw

features added:

• Debugger: Implemented history for memory panel.
• UI: Removed title bar from docked panes and improved resizing behavior.
• UI: Increased splitter bar size slightly and raised drag thresholds to reduce accidental pane undocking. 

bugs fixes:

• ANTIC: Fixed line buffer being cleared on blank lines.
• Debugger: Fixed history view sometimes not displaying effective address on an instruction after stepping from a memory access breakpoint.
• Debugger: Fixed horizontal scroll problems with overscroll in memory window.

author's comment:

• Fixed unnecessary line buffer clear in ANTIC emulation.
• Fixed history window sometimes not showing effective address on an insn after stopping on a memory access breakpoint.
• Adjusted horizontal scrolling in memory window and implemented history.
• Improved visual behavior when resizing the window with docked panes.
• Docked panes no longer show window captions.
• Re-enabled OS window theme for undocked window panes and enabled minimize/maximize buttons.
• Increased drag thresholds to reduce accidental undocking of window panes.

Altirra x86/64 4.40 test 16 4/08/2025

changes:

• nw

features added:

• Cheats: Cheat window is now modeless and resizable.
• Firmware: Redesigned firmware dialog.

bugs fixes:

• nw

author's comment:

• Firmware dialog redesigned. Those who have tracked the emulator's development have seen how much this has grown; it was far more manageable when there were only a dozen firmware types instead of the several dozen there are now. The tree view has been replaced with a filtered list view that is easier to read.
• The cheat dialog is now resizable and more readable in dark mode, and is now modeless so it can be kept open while the emulation is running.
• Disk drives dialog has improved dark mode support.
• Miscellaneous other dark mode fixes.
• Added protection against stack overflows in the custom device compiler.

Altirra x86/64 4.40 test 15 27/07/2025

changes:

• nw

features added:

• PerfAnalyzer: Added option for video trace channel frame size and resizable splitter to change the height of the displayed video channel.

bugs fixes:

• Cassette: Improved accuracy of Vorbis decoding.

author's comment:

• Fixed regression with 1050 full disk drive emulation.
• Fixed a minor issue in the Vorbis decoder.
• The video frame capture and display size are now adjustable in the performance analyzer.

Altirra x86 i x64 4.40 test 14 22/06/2025

changes:

• nw

features added:

• nw

bugs fixes:

• Input: Fixed crash after XInput controller is disconnected.
  
• Input: Added workaround for Xbox Wireless Controller being detected twice through DirectInput.
• Modem: Fixed intermittent failure to disable Nagle on outgoing connections.
• Modem: Outgoing connections no longer force off server-side echo.
• Modem: Binary mode negotiation is disabled when CR/LF translation is enabled.

author's comment:

• Modem no longer forces off remote echo when connecting as a client in Telnet mode.
• Modem no longer negotiates or allows binary mode when connecting with Telnet CR/LF translation enabled.
• Fixed some cases where modem TCP connection did not have Nagle's Algorithm successfully disabled.
• Fixed a crash when configuring input maps after disconnecting XInput controllers.
• Added workaround for Xbox Wireless Controllers connected over Bluetooth also showing up as duplicate DirectInput controllers.
• Fixed fake index pulse and seek timing for the Black Box Floppy Board.

Altirra x86 i x64 4.40 test 13 12/06/2025

Wee Ninja (2026, Playsoft) Wip. Check AtariAge 

changes:

• nw

features added:

• Devices: Added the Black Box Floppy Board.

bugs fixes:

• Debugger: Fixed .pathdump command repeating instruction lines.

author's comment:

• Fixed output multiplication in .pathdump output.
• Fixed some sounds not playing.
• Initial support for the Black Box Floppy Board.
• Added ATR mapping support for additional geometries supported by the Floppy Board, such as 5.25" 1.2M HD disks.

The Floppy Board is an add-on board for the Black Box that adds parallel floppy drive support to the Black Box. It's similar to the 1450XLD in design but more capable and reliable. With this version, the Floppy Board can now be emulated, but there are a lot of caveats:

• You need a 64K base Black Box firmware such as version 2.16 to have Floppy Board support. This originally came with the Floppy Board as a replacement ROM chip.
• Drive Configuration needs to have drive entries redirected to PBI Floppy 0-3, and those drives also configured in the FB options submenu. (You also need a SCSI drive attached to save the config.)
• The drive type, such as 5.25" HD, needs to be configured the same in both in Drive Configuration and in the emulator settings for the Floppy Board. The emulator needs this to compute the drive RPM, track count, and logical-to-physical sector mappings.
• The emulation configuration for the Floppy Board also selects which drive slots in the emulator are mapped to the PBI floppy slots. These do not have to match the mappings in the Black Box drive configuration, but it'll be pretty confusing if they don't.
• The Floppy Board only has 2K onboard RAM and does not have track buffering. It will not run faster with standard disks unless they are reinterleaved or reformatted.
• I still need to figure out what's going on with index sensor selection, as I had to invert it from Guus' schematics to get it to work, but this is causing the motor to stay running when there is no disk inserted.
• The drive seek sounds can be a bit loud at 3ms/track, need to modulate that a bit.
• There is an ambiguity problem for ATR images between 5.25" 40 track double-sided and 3.5" 80 track single sided. They have the same sector count, so the emulator can't tell which was used in an ATR. Thus, currently you will have problems re-reading a 3.5" 400K image stored in an ATR file.

This does confirm one thing I had long suspected: that Percom's side 2 mapping is indeed bugged and off by one from what it's supposed to be. The Floppy Board firmware has a setting for which side 2 mapping mode to use (XF551 / ATR8000 / Percom) and the Percom mode shifts everything by one sector from XF551, making the last logical sector inaccessible. 

Altirra x86 i x64 4.40 test 12 26/05/2025

changes:

• nw

features added:

• Display: Added Direct3D 11 custom effect support.

bugs fixes:

• Debugger: Improved debugger UI state update when non-debugger commands are used to resume execution.
• Firmware: The initial "autoselect" state for OS and BASIC firmwares is now always shown.
• GTIA: Fixed intermediate state when switching from CTIA to GTIA on the fly.
• IDE: CHS translation mappings now round down the number of cylinders instead of rounding up.

author's comment:

• Adds custom display effect support for Direct3D 11.
• Fixed cases where the debugger UI did not update when non-debugger commands were used to suspend/resume execution (pause, reset).
• The blank "autoselect" option for firmware is now always visible.
• The hard disk options dialog now rounds down instead of up when guessing cylinder counts from a raw file with no inherent CHS geometry, and allows direct LBA sector limit entry.
• Fixed a PRIOR state handling bug when switching between CTIA and GTIA on the fly.

The custom display effects code got a major refactor in this version. Besides supporting D3D11 as well as D3D9, it has a few more features now:

• Improved compatibility with .cgp effects due to supporting more undocumented features (//-style comments, PASSPREV, etc). Some .cgp effects still don't work for various reasons, such as using a field called "texture" which is an HLSL reserved keyword, but more effects work out of the box now.
• Custom effect profiling can be enabled by advanced cvar as well as in the .cgp file itself.
• Passes that don't reference the input can be cached for better performance.
• There are now more sample custom effects in the extras folder (which is now a .zip file).

There are issues specific to the D3D11 custom effects path that can cause issues. The biggest one is an annoying requirement specific to Direct3D 11, VS-PS linkage matching, where the vertex shader must output attributes in the same order as the pixel shader. This is not required by Cg or D3D9, and so effects not written with this in mind will fail to work in D3D11 mode unless adjusted.

Part of the reason for doing this is that I would like to drop D3D9 mode at some point, but the timeline for doing that is uncertain -- one reason being that Wine's support of D3D11 feature level 9.x is completely broken.

Altirra x86 i x64 4.40 test 11 21/04/2025

changes:

• UI: Options have been merged from Tools > Options into System > Configure System.
• Display: Bloom radius has been reset due to different units.

features added:

• nw

bugs fixes:

• Cassette: Fixed recording position not being reset properly when creating a new tape.
  
• Custom Devices: Fixed a compiler crash when using nested anonymous functions.
  
• Custom Devices: Added support for unsafe calls, including the ability to issue UI commands.
• Devices: SuperSALT test assembly voltage inputs now reflect computer model differences.
• Display: Fixed Enhanced CIO screen editor not wrapping characters properly on Delete Character commands.

author's comment:

• Firmware autodetect now explicitly labels common ATARIOSB.ROM as being related to Xformer.
• Fixed enhanced CIO display not wrapping characters properly between margins on Delete Character.
• Fixed a crash in the custom device compiler with certain patterns of nested anonymous functions.
• Added custom device support for playing sound clips, and a new Electronic Keyboard sample device.
• Added custom device support for issuing emulator UI commands.
• Fixed recording position not being reset properly when mounting a new tape, and auto-select Record when doing so.
• SuperSALT device now modifies SIO +12V, 9VAC, and port 3/4 +5V/GND results based on computer model.
• Merged Tools > Options into System > Configure System.

Altirra x86 i x64 4.40 test 10 23/03/2025

Quasimodo (Synapse Software, 1984)

changes:

• nw

features added:

• Disk: Improved timing correction when accelerating disk reads.

bugs fixes:

• Devices: Booting off the 1030 with internal firmware now registers T: device properly.
• Devices: Fixed 1030 ModemLink and T: handler download with SIO acceleration enabled.
• Disk: Relaxed standard disk emulator requirements on command frames and ignore overlapping commands for most disk emulation profiles.
• Save States: Fixed bug with active POKEY IRQs getting lost.

author's comment:

• Rewrote SIO bus handling to allow for per-device command processing.
• Disk emulator now ignores overlapping commands except for Indus GT profile, and allows early SIO command deassertion except for XF551 mode.
• Fixed bug with POKEY IRQs in progress getting lost on save state loads.
• Built-in 1030 firmware now properly installs T: device when ModemLink is booted but not run (e.g. BASIC on).
• Fixed 1030 standard emulation not booting ModemLink with SIO acceleration enabled.
• Improved timing for accelerated disk commands.

Altirra x86 i x64 4.40 test 9 10/03/2025

changes:

• nw

features added:

• nw

bugs fixes:

• nw

author's comment:

Has some more fixes to CP/M extent handling. Also, I dropped support for attempting to write sparse files, which I doubt you were hitting but wasn't worth the potential issues. Concrete info on the CP/M 2.2 directory format is hard to find, the main references are pretty vague with how some corner cases of extents are handled.

I did run into some weirdness with trying to concatenate test files with PIP, as sometimes concatenating files produced shorter output. Wasn't clear if it was due to PIP treating binary files with text or if there was something else causing it to malfunction.

Altirra x86 i x64 4.40 test 8 09/03/2025

Unversal Hero (1987, Mastertronic)

changes:

• nw

features added:

• Devices: Added The Pill device.
• Disk Explorer: Multiple files can now be exported at a time.
• Display: Added support for screen masks.
• Display: Improved scaling of bloom filter to different resolutions.
• UI: Reduced flickering on drive indicators when using full emulation disk drives.
  

bugs fixes:

• Devices: 1090 registers are now always visible regardless of PBI enable state to match the known PAL equations.
  
• Disk Explorer: Fixed crashes and directory corruption issues in CP/M filesystem handler.
  
• Display: Screen effects dialog no longer reports high dynamic range (HDR) is available when the display is configured for wide color gamut (WCG).
  
• HLE: Fixed a bug in the fast math acceleration hook for the normalization routine.

author's comment:

• Fixed bug in fast math acceleration normalize routine that could cause small errors.
• 1090 80-column registers are now always visible.
• Some rework internally in the Direct3D11 renderer.
• Fixed Screen Effects dialog sometimes reporting wide color gamut (WCG) displays as HDR capable.
• Updated bloom algorithm with better scaling to smaller displays.
• Fixed bright bar on the right side of screen when using a slot mask.
• Fixed slot mask counter-scrolling artifacts when panning.
• Reduced flickering of drive indicators when using full emulation disk drives.
• Fixed filename matching bug CP/M filesystem handler and crash with missing extents.
• Added The Pill device.

Altirra x86 i x64 4.40 test 7 17/02/2025

Hacker (1985, Activision)

changes:

• nw

features added:

• Custom Devices: Memory layers can now be auto-controlled based on OS/BASIC/Self-Test ROM visibility.
• Custom Devices: Improved error display when hot reloading the custom device definition file.
• Debugger: .tracecio now reports AUX2 on open commands.

bugs fixes:

• VBXE: Fixed hires artifacts when using attribute map with 1.26 core and extended color, or hires switching at the right border.

author's comment:

• Fixed two bugs in VBXE attribute map handling. RES=1 to switch to hires was broken in 1.26 core mode, and RES=0 was not forced properly at the right border.
• Custom devices can now auto-enable memory layers based on system ROM visibility. auto_enable: "osrom|basicrom|selftestrom" will automatically enable or disable a memory layer based on visibility of the OS, internal BASIC, or self-test ROM.
• Reduced duplicate/stale errors being displayed for custom devices.
• .tracecio now reports AUX2 on opens.

Altirra x86 i x64 4.40 test 6 8/02/2025

changes:

• nw

features added:

• PerfAnalyzer: Right-drag scrolling is now supported.
• PerfAnalyzer: Added native tracing mode, which profiles the emulator itself.

bugs fixes:

• Devices: Fixed Rapidus write-through improperly capturing writes to ROM or extended memory.
• Disk Explorer: Dragging out directories from a MyDOS disk no longer produces a bogus file.
• PerfAnalyzer: Fixed CPU profile window breaking temporarily after saving a trace.
• PerfAnalyzer: Fixed scrolling artifacts with frame boundary lines.
• PerfAnalyzer: Fixed lockup when pressing Tab.

author's comment:

• PerfAnalyzer: Fixed incorrect CPU history after saving trace.
• PerfAnalyzer: Fixed scrolling artifacts on frame lines.
• PerfAnalyzer: Right-drag is now supported.
• PerfAnalyzer: Fixed lockup when pressing Tab.
• PerfAnalyzer: Added native tracing support.
• Devices: Fixed Rapidus write-through conflicts on ROM and extended memory.
• Disk Explorer: Fixed dragging out of subfolders from a MyDOS disk producing a bogus file.

Altirra x86 i x64 4.40 test 5 20/01/2025

Panic Express (1986, Red Rat Software, LTD)

changes:

• nw

features added:

• nw

bugs fixes:

• Display: Fixed crash with blending enabled on extended height PAL screen.
• Display: Fixed regression in NTSC high artifacting on ARM64 only.
• Printer: Fixed rendering artifacts at edges when scrolling 1020 plotter output at high zoom.

author's comment:

• Reduced aliasing on screen masks by switching to a softer antialiasing filter.
• Fixed blending startup crash with extended PAL height displays.
• Fixed artifacts around edges when scrolling 1020 plotter views.
• Fixed canceling some load progress dialogs giving a blank error dialog.
• Fixed a crash in raw tape loading code if decoding errors occurred.
• Fixed dot/slot masks occasionally displaying as vertical stripes in Direct3D 9 mode.
• Fixed dark display in Direct3D 11 mode with screen mask enabled, PAL artifacting on, blending off or interlace on, and color correction disabled.

Altirra x86 i x64 4.40 test 4 18/01/2025

changes:

• nw

features added:

• Debugger: Added block detection support for Z80 disassembly.
  
• Devices: Improve timing precision of Indus GT full emulation.
• Disk: Add option for reinterleaving to 4:1 SD for SuperSynchromesh.

bugs fixes:

• nw

author's comment:

• Fixed Direct3D9 rendering artifacts with bloom enabled and some image formats.
• Z80 disassembly now supports block separators.
• Added option to disk dialog to reinterleave a disk to SD 4:1 interleave for Indus SuperSynchromesh.
• Improved timing accuracy of Indus GT full emulation so the Indus Doubler works.

Altirra x86 i x64 4.40 test III 12/01/2025

changes:

• nw

features added:

• Devices: Add device list is now sorted by name.
• Display: Move screen mask rendering to after color correction to reduce aliasing.
• Simulator: Increased scanlines run at a time to slightly improve speed.

bugs fixes:

• Devices: Fixed a crash when adding a device with certain nodes selected.
• Display: Fixed regression in D3D11 driver where bloom broke in full-screen mode.
• Input: Fixed console controller inputs being blocked in full-screen mode.
  

author's comment:

• Fixed crash in devices tree when adding new devices with certain nodes selected.
• Fixed console key input bindings in input maps being disabled in full screen mode.
• The Add Device dialog now has device names sorted.
• Fixed D3D11 bloom rendering with incorrect gamma in full-screen mode.
• Moved screen mask rendering to post color correction to reduce aliasing artifacts.

Altirra x86 i x64 4.40 test II 2/01/2025

changes:

• nw

features added:

• Debugger: Improved SIODATA trace channel output.
  
• Debugger: Added .devices and .device_info commands.
  
• Debugger: Static trace (st) command now has -b option to trace through BRK instructions.
  
• Devices: Added full emulation for 850 Interface Module.
  
• Devices: Internal 850 R: handler now blocks Break during concurrent I/O instead of ending concurrent I/O when it is pressed.
  
• Devices: Standard 850 emulation is now more consistent with DTR/RTS state.
  
• Display: Added slot type mask.
  
• UI: Added 850 error codes to error decoder.

bugs fixes:

• Custom Devices: Fixed crash when attempting to create a memory layer directly mapping beyond the end of a segment without explicit offset. .

author's comment:

• Adds full 850 Interface Module emulation.
• 850 standard emulation now matches the transfer speed of the 850, and fixed an issue with inconsistent DTR/RTS state.
• Updated internal 850 R: handler to v0.3 so it matches the Break key behavior of the newer 850 firmware instead of the older 850 firmware.
• On-screen error decoder (Ctrl+Alt+click) now interprets 850-specific CIO error codes.
• SIODATA logging channel now detects and interprets command frames.
• Added vertical slot mask type to mask rendering.
• Fixed a crash in custom device error reporting code.

More detailed explanation of the 850 stuff:

Like the other full emulators, 850 full emulation means that it is running the actual controller firmware instead of a high-level emulation of the 850. This also comes with the usual caveats: it requires the actual firmware, and some quality-of-life features aren't available with it, such as unthrottled operation. However, it also means you can test real corner cases like running code on the emulated 850 (and yes, warerat's firmware dumper does work). One caveat is that in some cases you may need to specify the baud rates for each port in the settings. This is because with full emulation, the emulator no longer has a direct way to tell what baud rate the 850 is using or expecting on each port, and this causes problems with output paths that are baudless like the file writer. Currently, the Auto detection will attempt to match POKEY's baud rate. This should work for the majority of cases that use concurrent I/O, but it may fail with the uncommonly used block write feature unless a specific baud rate is specified.

The full emulation also reveals a couple of things about the firmware. There are two firmware revisions in the wild, with CRC32s 9201359A and 2CF990B9. The [9201359A] firmware is the older revision and [2CF990B9] is the newer and more common revision. The 850 firmware sources from the Atari History Museum match the newer revision. The main differences between the two are documented in the different versions of the 850 Interface Manual, with the 1980 Owner's Manual documenting the older revision and the 1982 Technical Manual documenting the newer revision, with a note on getting older 850s upgraded at a service center. The main difference between the two is the handling of the Break key when concurrent I/O is active. In the older revision, pressing Break causes the R: handler to autonomously exit concurrent I/O mode, whereas in the newer revision, the Break key is disabled and ignored. However, there are also two undocumented changes: the newer revision also recognizes P2: for printer access, and raises the printer I/O timeout from 5 seconds to 30 seconds. The relocator and handler downloads are slightly longer on the older revision as well, meaning that some software won't work with it -- notably BobTerm can't auto-download the R: handler.

Accordingly, a couple of adjustments have been made to the 850 standard emulation to improve accuracy. The internal R: firmware that's built-in and included on the Additions disk has been updated to v0.3 with the Break key behavior now matching the newer firmware, and the transfer rate of the firmware download has been slowed down to match the 850, which like the 1050 is a little bit on the slow side. A fix has also been made to control signal handling as DTR and RTS weren't consistently being set on the attached device. The main potential impact of this is that the modem will not auto-answer on default settings unless DTR is asserted or the DTR handling mode is changed with the AT&D command. BobTerm at least makes sure that DTR is asserted at startup, but other software might not.

Finally, in not 850 related news, slot mask support has been added, which is a mask type with fine vertical slots instead of unbroken vertical stripes as in an aperture grille. It is the mask type used by at least some versions of the Commodore 1702 monitor.

Altirra x86 i x64 4.40 test I 22/12/2024

This prerelease version:

changes:

• nw

features added:

• Display: Added support for screen masks.

bugs fixes:

• nw.

author's comment:

• Adds support for display screen mask emulation, currently supporting aperture grille (Trinitron) and dot triad patterns. This is set up in View > Adjust Screen Effects. It works best with a high resolution display (e.g. 2560x1440 or higher) with high brightness or HDR enabled, as this requires even higher peak brightness than scanlines. The renderer will try to compensate if bloom is enabled, but you'll see moiré patterns on bright colors if you push it too hard.

Photo Altirra 4.40 Nowe efekty zniekształcenia obrazu.