New Version Of The 8bit Atari Emulator Altirra

This Atari 800, 800XL and 130XE emulator for Windows has seen another update so let’s find out what’s new in this one:

[features added]
Debugger:
• Added .diskorder command to force phantom sector load order.
• Added .dma command to dump current ANTIC DMA pattern.
• Added .caslogdata to diagnose cassette data read failures.
• Added .pia command to dump PIA state.

Disk:
• Added support for command $4E (Read PERCOM Block).
• Added support for reading Diskcomm (DCM) images.

Cassette:
• CAS images and mono WAV files now play data as audio.
• The SIO acceleration engine now reports diagnostics about damaged blocks to the console window.
• Made accelerated read routine more robust against interpreting garbage as the start of block sync.
• Optimized WAV processing routine.
• Added command to unload tape.
• Added emulation of feedback from SIO motor control line into audio input.

UI:
• Added command to reset window layout.
• Drag-and-drop is now a synonym for the Open Image command.
• Added more key mappings.
• Added Boot Image command to unload all existing cartridges/disks/tapes and cold reset after loading an image.
• Added debugging option to dump raw audio to disk (32-bit float @ 63920.4 NTSC / 63337.4Hz PAL).
• Added .com to list of file filters for the Open Image/Boot Image commands.
• Added enhanced text display mode.

Simulator:
• Added support for loading OS-A kernel ROM.

GTIA:
• Added support for PAL artifacting.

[bugs fixed]
UI:
• Mapped Ctrl+alpha/num and Ctrl+Shift+alpha/num keys.
• Arrow-keys now auto-repeat.
• View > Display works when the debugger is disabled.
• Fixed window activation and sizing problems when toggling full screen mode.
• This simulation is now throttled in full-screen mode.

CPU:
• Implemented TDC instruction in 65C816 mode.
• Implemented undocumented $93 (SHA) and $BB (LAS) opcodes.
• Fixed flags on $9C (SHY) opcode.
• Removed bogus 65C816 opcode ($DC) in 6502 decoder.

Cassette:
• Fixed desync between audio and data after accelerated load.
• Audio/data channels are no longer swapped when processing stereo input.
• Raised cutoff on control line low-pass filter to fix reliability problems at turbo baud rates.
• Fixed incorrect SIO return code for accelerated cassette reads.

Cartridge:
• Fixed MMU mapper so that the cartridge ROM now overrides BASIC at $A000-BFFF.
• TRIG3 is now deasserted when $A000-BFFF is unmapped.
• The second bank setting for Bounty Bob Strikes Back! cartridges is now saved in save states.

Disk:
• Added support for weak bit emulation in VAPI images.
• Fixed VAPI image read errors when missing sectors are present.
• Fixed incorrect FDC status when loading long sectors that set the “lost data” status bit.
• SIOV/DSKINV acceleration handlers set more kernel variables for better compatibility.
• Abort acceleration attempt when disk buffer contains SIO timeout flag (TIMFLG).
• Adjusted sector read delay to increase VAPI image compatibility.
• Fixed cases where the virtual read/write setting was not obeyed properly.

GTIA:
• Changes to GRAFPx/GRAFM are latched and no longer affect a sprite image that is already shifting out.
• Increased timing precision of console speaker from 28 cycles to single cycle.
• Fixed bug that caused some apps to misdetect the video mode as SECAM.
• Adjusted timing for mid-screen changes to P/M graphics and color registers.
• CONSOL output bit 3 wasn’t affecting input bit 3.
• VDELAY now masks DMA fetches rather than actually delaying loads.

POKEY:
• Fixed random crash in stereo mode.
• 15KHz and 64KHz clocks are no longer joined between the left and right channel chips.
• The channels now have the correct 0-3 clock skew for reading the noise generators.
• Implemented channel 1/2 inversion when not in volume-only mode.
• Implemented non-linear mixing.
• Audio plays again when initialization mode is active.
• Implemented serial force break bit (SKCTL bit 7) affecting two-tone mode.
• STIMER now resets output channel states properly.
• Asynchronous serial input mode now holds down timers 3 and 4 again when a byte is not shifting in.

HLE:
• The math pack is now emulated even if the acceleration option is disabled.
• POTGO is now strobed during vertical blank stage 2 processing.
• STRIG2/3 are now updated from TRIG0/1 instead of TRIG2/3 for XL/XE hardware compatibility.
• Fixed bug where POKEY was put into initialization mode after an unaccelerated SIO transfer.
• POKEY audio channels are now shut off after an SIO operation.
• Added keyboard click.

ANTIC:
• Two-line resolution mode now reloads GTIA every scan line.
• Fixed timing when using read-modify-write instructions to trigger WSYNC.

Simulator:
• Memory banking wasn’t updated properly on changes to the port B data direction register.

Download from the homepage or below.

Altirra For Windows (431.4 KiB, 26 Downloads) - Version 1.4

Altirra Source Code (1.1 MiB, 11 Downloads) - Version 1.4

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