Readme of ZXAM Spectrum Emulator AGA v1.3 ß --------------------------------------------- (read the addendum for v1.3 ß, below) Please, read the DOCeng to know how to use the emulator. Keep in mind that this is a ß version, that means, unfinished and with possible bugs, but I would like that the people test the emulator and give me their opinion, criticism, etc... If you know about a Dragon 32 emulator for the Amiga, please let me know. I know a friend of mine that wants that I program such an emulator. I think that some times there is a justification for murder...(AARGH!!) If you want to contact me, please send me a letter to the address that appears in the DOC. If you know spanish, and you aren't afraid of big telephone bills, read the LEEME!! file to contact me through a spanish BBS. The icons are designed for an 8 colours WorkBench. If you want to include the package in your Public Domain library, you can do it only if the package remains complete and unmodified, and you don't charge more than the post and packing charges. Along with the emulator there is a drawer with 23 Spectrum programs, compressed with PowerPacker. The package can be included in a magazine's coverdisk, or uploaded to any BBS. Enjoy it (or suffer it...) Antonio J. Pomar Rosselló (Palma de Mallorca, SPAIN) >>>>>>>>>>>>>>> ADDENDUM FOR VERSION 1.3 ß <<<<<<<<<<<<<<<< The main motivation for the release of version 1.3 ß is the addition of the LOAD/SAVE to tape. This is not a definitive version, but there were many requests from people that have sent to me messages to TANIT-BBS. This way the LOAD routine can be tested on different configurations, to report any kind of problem. Moreover, version 1.3 ß includes some attempts of synchronization for stabilize the emulator, but they aren't completed. I need information about the result of these attempts in other CPUs (68030/50MHz or 68040). Changes since version 1.2 ß are: LOAD FROM TAPE: The LOAD routine is a patch of the ROM LOAD routine. This patch is partial. That means that 90% of code executed while LOADing is the Z80 original routine. This way the emulator behaves like the original Spectrum, you can see the screen data and attributes loading, can do BREAK by pressing the space key, the border shows the old "loading colours" and the FLASH attributes are still "FLASHing" during the LOAD. All this works even with an Amiga 1200 without FAST memory and in colour mode!!. The LIMITATIONS of the patch are: -The border lines aren't perfect, but almost. Some border change are missed because of some interference between the CPU and the copperlist. I could do a perfect border, but the LOAD/SAVE lines aren't worth the speed loss. -The sound from tape can be heared ONLY DURING THE LOAD. That means that you will need to search the beginning of the program with the cassette disconnected from the computer. A software emulation of the hardware connection between MIC and EAR connectors would be a severe slowdown of the emulation. -NEEDS A CUSTOM INTERFACE: although I think that this is not a limitation because the interface that I have designed is much more cheaper and practical than a sound sampler. This interface plugs into the Joystick port. You can plug and unplug it even with the computer switched on. The 2 (yes, TWO!) components used in the interface are for protection of the computer. If you want, you can make a through-port to connect the interface and the joystick at the same time. With this interface you can leave the printer connected to the parallel port permanently. -Because the LOAD is a patch, forget about loading Turbo games (al least, for the moment...;-). -In systems with slower CPUs isn't recommendable to touch the keyboard while loading, because any key press/release will cause an interrupt, that can produce the dreaded "R Tape loading error". You only need to touch the keyboard to do a BREAK. Well, I have to say that the effectiveness of the patch is much better than any prevision. During the first testing of the patch I have connected the internal Spectrum +2A cassette to the tape interface, and tried to load simultaneously the same program in the +2A and in the Amiga 1200. The aim of the test was to find some programs that the +2A can load and the Amiga 1200 can't, to use it to adjust the timing of the patch. The inesperate results were that the computer with problems to load some programs was the +2A, while the Amiga 1200 loaded everything that I have throwed to it ;-). I have passed to disk 83 programs during the tests. SAVE TO TAPE: This is a very easy one. Actually, this is not a patch, otherwise it is a REAL TIME SAVE. It is the Z80 that is sending the data to the tape. The only thing that I haved to do is to stabilize the sound output. The same explained above about the keyboard and border is applied to the SAVE. The data saved with the emulator has been loaded succesfully by the emulator itself and by my ZX Spectrum +2A. SOUND: The emulator includes a "sound stabilizer" that tries to enhance the cleaness of the sound. This stabilizer is the real guilty of the REAL TIME SAVE, and the pure sound of the BEEP command. Some games sounds now a lot better (like the ULTIMATE ones), but some others have slowed down slightly. Anyway, this stabilizer is experimental, and will be much better when I can test it thoroughly with a computer with a fast CPU.