vb81's Homepage

vb81 - Sinclair ZX81 Emulator

Hot on the heels of the Speccy emulator, is an emulation of the Spectrum's older brother, the ZX81. It uses the same VB core as vbSpec, but due to differences in the display hardware and processor speed of the ZX81, this will run happily at full speed on just about any PC that is capable of running Windows at a usable speed.

NOTE: I haven't updated vb81 in quite some time, however there is a great new version of vb81 by XavSnap which includes additional features such as an integrated disassembler and support for additional hardware such as the Larken disk controller and both the Memotech and G007 high-resolution graphics cards. It is available from http://zx81.vb81.free.fr/ and is well worth a look!

Features in vb81 Version 1.30
Version 1.30 contains the following new features:-

Significantly faster Z80 emulation core. You should have no problems running vb81 v1.30 at full speed in both SLOW and FAST modes even on a relatively low-spec Windows system
Improved performance of both standard and hi-res display routines.
Fixed a couple of bugs in the keyboard support which caused many games not to respond to key-presses.
Added new 3x display magnification option.
New 'Allow writes to shadow ROM area' option allows access to the 8K-16K area of the memory map. Some games use this to provide hi-resolution graphics and custom character sets (FROGGER- for example).
Fixed a bug in the interrupt routine that caused FRAMES to be incremented wrongly. Some games such as Rocket Man froze after a few seconds or minutes of playing.
Fixed some minor bugs in the Z80 emulation. I believe the CPU emulation is now 100% correct in terms of timing, flag operation, and support for undocumented opcodes -- let me know if you think otherwise!
Playtested against literally hundreds of ZX81 games to ensure full compatiblity. The only known problem is ZX-Xtricator, which has a custom overscanned hi-res display routine that does not yet work properly with vb81.

Other Features in vb81

Emulates both SLOW and FAST modes.
Emulates psuedo hi-res graphics routines as used by innovative games such as Forty Niner, Rock Crush, Dan's Revenge, and Rocket Man.
Supports loading and saving of standard ".P" tape files used by various other ZX81 emulators.
Includes optimised 'standand' and 'double-size' display options.
Emulates undocumented Z80 op codes, and correctly emulates all bits of the Flags register.
Native 32-bit Windows application runs under Windows 95, Windows 98, NT, and Win2K.
Emulates Memotech's MemoCalc spreadsheet ROM.

Download the essential binary files - (80KB) - If you already have the Microsoft VB6 runtime files on your PC (MSVBVM60.DLL, VBA6.DLL and COMDLG32.OCX are required by vb81) then this download is all you need to run the emulator on your PC. There are also some ZX81 games included in the ZIP file: 3D Monster Maze, The Gauntlet and ZX-Galaxians. Use this option if you are upgrading from an earlier version of vb81..

Download the complete binary distribution - (2.20MB) - A complete installer that contains all of the runtime libraries necessary to run the emulator. It has an uninstall option too, but you won't be needing that :) 3D Monster Maze, The Gauntlet and ZX-Galaxians games are also included.

Download the source - (64KB) - Build it yourself with VB6. The source code is distributed under the terms of the GNU General Public Licence (GPL).

Screenshots

3D Monster Maze Intro 3D Monster Maze in action
3D Monster Maze - J.K. Greye Software

The Gauntlet Intro The Gauntlet in action
The Gauntlet - Colourmatic Computing