Win994a-TI-99/4A Simulator for Windows

Version 3.008

(Screens are from V3.002)

Win994a is a TI-99/4A simulator written by Cory Burr that installs and runs in the Windows environment.

The following is from the help manual:

Win994a is not a perfectly accurate emulation of the TI-99/4a; and it was never intended to be. The author decided not to implement certain aspects of the TI-99/4a either because they are rarely used or were considered of "no-value-added". The author vigorously apologizes to those users who will miss a favorite peripheral or item of functionality. The list below details the various functionality provided by the Win994a Simulator.

General Functionality

• Boots and runs all console ROM and GROM based functions including console BASIC.
• CRU bits for the keyboard are implemented; some CRU bits for the Disk Controller and RS232 Interface are implemented.
• TMS9918a video chip functionality is implemented.
• TMS9919 sound chip functionality is implemented.
• TMS5520 speech synthesizer chip is partially implemented.
• Full floppy disk and disk controller functionality.
• Full cassette tape functionality for CS1.
• 32k Memory Expansion supported.
• PIO and RS232 ports are supported, but using a different method than the original TI99/4a.
• Support for one joystick input (using numeric keypad).
• Runs over 200 cartridges correctly.  Cartridges that depend on non-implemented CRU bits or non-documented video chip operation will fail.  Other cartridges may fail due to bugs in the Win994a Simulator (major author apology).

Specifics

• All TMS9940 CPU instructions are implemented. CPU clock ticks are accumulated for both instructions and fast/slow memory accesses. When enough clock ticks have been accumulated for 1/16 of a second real elapsed time, Win994a checks the high precision clock (available in the PentiumPro and above processors) and gives up enough of the time slice so that accurate running time is maintained.
• Console based cassette tape functions for CS1 supported.
• Console ROM and multiple console GROM functionality implemented.
• Multiple peripheral based ROMs supported.
• Multiple cartridge based ROMs, GROMs, and RAM supported.
• TMS9918a: Uses DirectX for all operations. Video modes GRAPHICS, TEXT, MULTICOLOR, BITMAP, BITMAP-TEXT, and BITMAP-MULTICOLOR are implemented. Sprites, sprite coincidence, screen blanking, and vertical interrupt operations are implemented.
• TMS9919: Uses DirectSound for all operations. All three voices and noise channel supported.
• TMS5520: Speech synthesizer functions partially implemented; should be used with Speech Editor cartridge or Extended Basic cartridge only.
• Disk Controller and three floppy drives fully supported.
  
• PIO and RS232 ports are supported, but using a different method than the original TI99/4a. PIO/1, PIO/2, RS232/1, RS232/2, RS232/3, and RS232/4 provide six separate pathways for making printouts through Window's print system. They do not provide input/output capabilities with the PC's actual hardware ports.
• Support for one joystick input (using the keyboard numeric keypad) is implemented.

(Screen Shot of Win994a Help File)

Cartridges Win994a  Now Uses a Special Cartridge File Format
	When selecting cartridges, a description of the cartridge is shown in the bottom pane, and a scan of the manual cover is shown to the right!

If you want to add cartridges, the 'cartridge creator' function makes it easy to do.

Disk Support
Cassette Support
Preferences
Four different window sizes

Download Win994a:

• As always, there are several minor fixes to Win994a Simulator. Some are cosmetic, but a few are operational. One of these involved the way double sized sprites utilize character definitions. Most people will not notice many of these fixes.
• Some major work was done to enhance correct execution timing. The Simulator now supports three different methods of clock timing based on the machine you have and the clock resources it has available. Another area of timing that was corrected involves speech. A significant amount of work resulted in improving Win994a's speech so it works more like a real TI machine.
• The Disk Manager application has been completely revamped and rewritten. Now it handles both floppy and hard disk files. This makes it possible to directly copy files between these two different types of storage media. 
• The assembler application has been revised and updated to write its output files directly into both floppy and/or hard disk container files. This allows for a much faster and convenient method of writing assembly programs. In addition, the assembler can produce binary files that Win994a can directly import into new cartridge applications. The process of writing and developing new TI cartridges just got easier
• All you assembly programmers, please see a new document that describes the more technical aspects of developing code for Win994a. A few new machine code instructions were added to Win994a and the assembler to support traditional stack manipulation and memory paging. All this should make writing large programs for Win994a more straight forward.

Resources:

Win994a is unsupported software, so a special help forum has been created:
Win994a Support Forum
Please post any questions or comments here and perhaps other users can provide some assistance.

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The owner of this site does not guarantee or necessarily test any of the programs or files available for download from the site. Downloading and installing any files is done at your own risk.