Atari 800/800XL/130XE emulator for Windows has been updated. Changes:
[features added]
* Debugger: Added .diskorder command to force phantom sector load order.
* Debugger: Added .dma command to dump current ANTIC DMA pattern.
* Debugger: Added .caslogdata to diagnose cassette data read failures.
* Debugger: Added .pia command to dump PIA state.
* Disk: Added support for command $4E (Read PERCOM Block).
* Disk: Added support for reading Diskcomm (DCM) images.
* Cassette: CAS images and mono WAV files now play data as audio.
* Cassette: The SIO acceleration engine now reports diagnostics about damaged blocks to the console window.
* Cassette: Made accelerated read routine more robust against interpreting garbage as the start of block sync.
* Cassette: Optimized WAV processing routine.
* Cassette: Added command to unload tape.
* Cassette: Added emulation of feedback from SIO motor control line into audio input.
* UI: Added command to reset window layout.
* UI: Drag-and-drop is now a synonym for the Open Image command.
* UI: Added more key mappings.
* UI: Added Boot Image command to unload all existing cartridges/disks/tapes and cold reset after loading an image.
* UI: Added debugging option to dump raw audio to disk (32-bit float @ 63920.4 NTSC / 63337.4Hz PAL).
* UI: Added .com to list of file filters for the Open Image/Boot Image commands.
* UI: 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.
* UI: Arrow-keys now auto-repeat.
* UI: View > Display works when the debugger is disabled.
* UI: Fixed window activation and sizing problems when toggling full screen mode.
* UI: This simulation is now throttled in full-screen mode.
* CPU: Implemented TDC instruction in 65C816 mode.
* CPU: Implemented undocumented $93 (SHA) and $BB (LAS) opcodes.
* CPU: Fixed flags on $9C (SHY) opcode.
* CPU: Removed bogus 65C816 opcode ($DC) in 6502 decoder.
* Cassette: Fixed desync between audio and data after accelerated load.
* Cassette: Audio/data channels are no longer swapped when processing stereo input.
* Cassette: Raised cutoff on control line low-pass filter to fix reliability problems at turbo baud rates.
* Cassette: Fixed incorrect SIO return code for accelerated cassette reads.
* Cartridge: Fixed MMU mapper so that the cartridge ROM now overrides BASIC at $A000-BFFF.
* Cartridge: TRIG3 is now deasserted when $A000-BFFF is unmapped.
* Cartridge: 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.
* Disk: Fixed VAPI image read errors when missing sectors are present.
* Disk: Fixed incorrect FDC status when loading long sectors that set the "lost data" status bit.
* Disk: SIOV/DSKINV acceleration handlers set more kernel variables for better compatibility.
* Disk: Abort acceleration attempt when disk buffer contains SIO timeout flag (TIMFLG).
* Disk: Adjusted sector read delay to increase VAPI image compatibility.
* Disk: 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.
* GTIA: Increased timing precision of console speaker from 28 cycles to single cycle.
* GTIA: Fixed bug that caused some apps to misdetect the video mode as SECAM.
* GTIA: Adjusted timing for mid-screen changes to P/M graphics and color registers.
* GTIA: CONSOL output bit 3 wasn't affecting input bit 3.
* GTIA: VDELAY now masks DMA fetches rather than actually delaying loads.
* POKEY: Fixed random crash in stereo mode.
* POKEY: 15KHz and 64KHz clocks are no longer joined between the left and right channel chips.
* POKEY: The channels now have the correct 0-3 clock skew for reading the noise generators.
* POKEY: Implemented channel 1/2 inversion when not in volume-only mode.
* POKEY: Implemented non-linear mixing.
* POKEY: Audio plays again when initialization mode is active.
* POKEY: Implemented serial force break bit (SKCTL bit 7) affecting two-tone mode.
* POKEY: STIMER now resets output channel states properly.
* POKEY: 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.
* HLE: POTGO is now strobed during vertical blank stage 2 processing.
* HLE: STRIG2/3 are now updated from TRIG0/1 instead of TRIG2/3 for XL/XE hardware compatibility.
* HLE: Fixed bug where POKEY was put into initialization mode after an unaccelerated SIO transfer.
* HLE: POKEY audio channels are now shut off after an SIO operation.
* HLE: Added keyboard click.
* ANTIC: Two-line resolution mode now reloads GTIA every scan line.
* ANTIC: 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.

http://www.virtualdub.org/altirra.html