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Text File | 1992-07-26 | 23KB | 447 lines

Sinclair ZX Spectrum Emulator V1.41 - 27/7/92 - by G.A. Lunter For those who do not know enough Dutch to read the manual Z80.DOC, a summary follows in English: 1. Introduction & Registration The Spectrum Emulator 'Z80' is a program that emulates a Sinclair ZX Spectrum 48K model 2 or 3, with Interface I, complete Z80, screen, keyboard, interrupt and sound emulation, full tape support (normal and speedload), and has many additional features such as Interface I RS232 in/output to PC devices (file, COM, LPT), many Spectrum joystick interfaces controllable by PC cursor keys, analog and digital PC joysticks, conversion programs that make GIF files out of Spectrum screens, turn Spectrum BASIC programs into PC textfiles and vice versa, convert snapshot files of VGASPEC and JPP (also Spectrum Emulators) into .Z80 files (this Spectrum Emulator's snapshot format) and vice versa, a DISCiPLE disk read program, an extensive manual, and more! The Spectrum Emulator is a Shareware-program. You are allowed to try it for a month, and if you like it you should register for it. When registered, you will receive a registered version of the Spectrum Emulator, four utilities and the sourcefiles of the Emulator. The shareware-version of the Emulator is fully functional, except for the Tape support and the possibility of slowing down the Emulator, which are available only to registered users. Registered users will also be informed of future updates of the Emulator. The shareware package of the Spectrum Emulator consists of the following files: Z80.EXE - The Emulator ROMS.BIN - The ROMs of the Spectrum and SamRam GETRS.COM - Utility to send programs from Spectrum to PC SAVESPEC.BAS - Idem, see paragraph 6. DIAGRAMS.Z80 - Diagrams for tape interfaces, and calibration Z80.DOC - Documentation file --- in Dutch LEESMIJ.DOC - Summary of documentation --- in Dutch NIEUW.DOC - What's new SUMMARY.DOC - This file These are the utilities you'll receive upon registering: CONVERT - a general conversion program for converting many Spectrum file formats into PC formats and vice versa. It can produce GIF files of Spectrum screens, make text-listings of programs and more. CONVZ80 - Translates snapshot files from VGASPEC's .SNA and JPP's .SP formats to this Emulator's .Z80 format and vice versa. Z80DUMP - Shows the contents of the header of a .Z80 file DISCIPLE - Reads DISCiPLE diskettes. It translates normal files into files that can be read using the Interface I's LOAD *"b" command, and translates snapshot files into .Z80 files. The registration fee is 35 Dutch guilders, 10 English pounds, 20 US$, or 35 Deutsche Marken. For Dutch users, the registration fee is Hfl 25,--. Please send the money to: G.A. Lunter, Aweg 11a, 9718 CT Groningen, The Netherlands If you can, please use Eurocheques or send it cash. If you use Eurocheques please do NOT fill in the place (or fill in 'Groningen'), because otherwise I have to pay a large commission. Unfortunately I cannot accept creditcards. Also, please don't forget to give me your address (including your country.) It is also possible to reach me by Internet via Johan Muizelaar: his e-mail address is mouse@frw.rug.nl 2. Getting Started The Spectrum Emulator can be configured in many ways. Most of these configurations can be altered from the Main Menu. You enter the Main Menu by pressing F10. Other configurations must be specified when the Emulator is loaded, by putting the right 'switches' on the command line. The following switches are possible: -h Hercules graphics -x Extended Hercules graphics -c CGA graphics -e EGA/VGA graphics -p Plantronics graphics -q Plantronics (greytones) -n Standard Spectrum (without IF1) -s Spectrum with SamRam -jk Kempston joystick (instead of Cursor) -j1, -j2 Sinclair joystick 1,2 (instead of Cursor) -kk Do not use a digital or analog joystick -kz Use digital Zandbergen joystick -d Double interruptfrequency -l LDIR/LDDR emulation -f Faster FLASH emulation -r R register emulation -w 16K IF1 bankswitch -2 Emulate Issue-2 Spectrum -g No sound -bN Tape I/O via LPTn -yl, -yh Low, high video sync. -aN Spec RS232 output to LPTn -oN Spec RS232 output to COMn -iN COMn to Spec RS232 input -tF Spec RS232 output to file F -uF File F to Spec RS232 input -znnn.n Force relative snelheid nnn.n% -? Short summary of possible options (in Dutch!) Normally, the Spectrum Emulator tries to find out on his own which video adapter should be used. You can bypass this by specifying directly which one should be used, using the switches -h, -x, -e, -p or -q. If you have a Hercules adapter, try using -x; it gives a better result and works on most systems. When -n is specified, the Emulator is stripped to the bone: only the original Spectrum is emulated, without the Interface I. If you have memory problems, this might be useful. Options -jk and -j1, -j2 control the joystick emulation. Normally, the PC-cursor keys are attached to the Spectrum cursor keys, 5 6 7 8 and 0. (The TAB key, and the 5, 0 and . keys are emulated as 'Fire', 0 in the case of cursor keys). The Kempston joystick is emulated when -jk is specified, and the Sinclair 1 and 2 joysticks respectively when -j1 or -j2 is specified. The Spectrum joystick can also be controlled by an analog PC-joystick or a digital joystick. If a joystick is attached it will automatically be made to control the Spectrum joystick. If you don't want joystick-control, option -kk disables the analog joystick. Option -kz enables the digital Zandbergen joystick. (A wiring diagram of the Zandbergen digital joystickinterface is to be found in the file Z80.DOC) Option -d results in a twice as high as normal interrupt frequency. This may speed up some games, slow down others, and makes the keyboard respond more promptly when typing in BASIC programs on the Emulated Spectrum. The -l option slows down the LDIR and LDDR instructions of the emulated Z80. These instructions are carried out very much faster relative to the other Z80 instructions. Some programs, notably Jetset Willy and Manic Miner, will get irritatingly fast if this option is not used. If -f is specified, the Flash-frequency is doubled. This is not particularly useful, although it might be on the slowest PC's. Option -r is rarely needed. Only when this option is specified the R-register of the Z80 will behave correctly, increasing by one every time an instruction is carried out. Otherwise the R-register will behave as an random-generator. Activation the R register emulation will slow down the Spectrum Emulator by about 30%. This options is only useful if you want to load copy-protected games from tape: these games use the R register for protection purposes. From version 1.25 onwards, option -2 is added, because of compatibility problems with older Spectrum programs. PRINT IN 254 will give a number lower or equal to 191 on Issue 3 Spectrums, but gives 255 (when no keys are being pressed) on Issue 2's. Option -g turns off the sound. Options -a, -o, -i, -t and -u are used to control the communication of the emulated Spectrum with the PC. The RS232 channel of the Interface I can be attached to COM-ports (bidirectional), to the LPT ports (unidirectional) and to files (bidirectional). It is more convenient, however, to use the Main Menu to alter these settings instead of specifying them at the command line. Option -z can be used to slow down the Emulator on fast machines. This option is only available to registered users. The Emulator may be slowed down up to a factor four, and will by default run as fast as it can. After the z the desired speed as a percentage of the speed of the real Spectrum should be given. For instance, "-z 100" will make the Emulator run exactly as fast as the real Spectrum, "-z 0" will make it run as slow as possible. This option is available only to registered users. Occasionally, the moving characters of a Spectrum program tend to 'flicker' on the Spectrum Emulator, even if they didn't do so on the real Spectrum. If this happens, try using -yl or -yh. Usually -yl works. Finally, a filename can be specified on the command line. This file will be regarded as a .Z80 file, and loaded into the Emulator. It is no necessary to specify the extension .Z80. 3. Keyboard Special keys are: F1 = Help page F2 = Save Spectrum program (as .Z80 file) F3 = Load Spectrum program (as .Z80 file) F4 = Change settings F5 = Generate NMI ALT-F6 = Generate Reset F7 = Enter Real mode (see next paragraph) F10 = Enter Main Menu ALT, CTRL = Symbol Shift ESC = EDIT (Shift-1) PC-cursorkeys = Joystick (kempston, cursor or sinclair 1-2) TAB, 0, 5, . = Fire! (joystick) (0,5,. on numeric keypad) CTRL-BREAK = Quit the Emulator Normally, an NMI generates a reset or does nothing at all. When the SamRam is active (use option -s when starting the Emulator), you can, among other things, use the build-in disassembler, which is very MONS-like, at least visually. 4. Tape support Version 1.40 of the Spectrum Emulator includes full tape support. This means that all Spectrum programs can be loaded directly from tape. This includes programs that use speedload! Also, Spectrum programs that run on the Emulator can be saved back to tape to be loaded into a real Spectrum. Tape support is, however, available to registered users only. To connect your PC to a taperecorder, you'll need a tape-interface. In the file DIAGRAMS.Z80, a Spectrum program that can be run by the Emulator, there are two diagrams for tape interfaces, that use the LPT port to connect the PC to a tape recorder. The first diagram involves an OpAmp and works very well. The second, simpler diagram also works well, but the setting of the volume is more sensitive, and it must be cali- brated. The program DIAGRAMS.Z80 includes a small program that tests the interface, and can used to calibrate the simple interface. Just type LOAD "" to start loading a Spectrum program from tape. A window appears on screen, saying that the Emulator is loading a header-type block from tape of 17 bytes. If you use an EGA or VGA video adapter you should see bars in the border just as on an ordinary Spectrum. After each block (that is, after a header or data-block) the window disappears and the Emulator continues emulating. Any tape error also causes the window to disappear, and leaves the ROM to handle the error in the usual way. Pressing any key (not only the space bar) causes a BREAK to be generated. In this mode of loading, a small subroutine of the Emulator loads the program from tape. It is not the emulated ROM that loads the program. This means that even with a slow PC you can load programs, and that the speed of the emulated Spectrum does not need to be 100%. It also means that it is impossible to load programs that use own load-routines, such as speed-loaders. There is another mode, the so-called Real mode, in which the Emulator runs smooth and allows for the loading of speed-saved programs. In this mode, the keyboard cannot be used and the PC-screen is not updated. If you want to load a Spectrum program in Real mode, you need a fast computer. The Emulator should run at at least 100%, preferably at 110%. If the Emulator runs too fast, it should be slowed down to 110% as closely as possible. (On very fast computers, the real speed may be slightly off the computed speed, and a little experimentation may be needed to get the best results.) Type LOAD "", and press F7 to go to the Real mode. A small window appears, and from now on nothing happens on screen anymore (except for bars in the border if you are loading and use EGA of VGA.). At the short breaks between the blocks you may press U to update the screen and see what's happened. Never press U during loading, since tape errors will result. If the program has loaded, you can return to the normal mode and play the game. If you try to load speed-saved programs, you'll notice that some may crash upon loading or even before. This is because many speed-saved programs are protected in many ingenious ways that make use of rarely needed properties of the Z80 chip. If this happens, try using options -r and -l (R-register and LDIR emulation). The first option has the drawback that it slows down the Emulator so that it may be unable to load the program in Real mode. In this case, and also when your computer is slightly too slow even when -r isn't used, you can try to let your tape-recorder run slower than normal. On some EGA/VGA display cards, it is possible that 'snow' appears on the monitor during loading. Unfortunately, there is no way to avoid this, but it causes no problems. Saving is also possible in two ways, but I don't see a point in saving programs in real mode. The result is always better if you use the built-in save routine, and it works much easier. Finally, there is an easy way to save complete Spectrum programs in a standard format to tape, which can be loaded by normal Spectrums. This method uses the software of the SamRam. This is how it works: start up the Emulator using switch -s and load the program (as .Z80 file, or from tape). At a convenient point, press F5 to generate an NMI, and press S to save the program, and S to enter a filename. Press enter, and the program will be saved. It is understood that this method may NOT be used to copy commercial programs!! 5. .Z80 files The .Z80 files are a slightly packed Spectrum memory dump format. At any point in the program, you can save the current state of the Spectrum in such a file, by going to the Main Menu and using option 'Save Program'. It can then be loaded back, by specifying the filename on the command line, or using option 'Load Program'. For the insiders, an explanation of the format of .Z80 files will now be given. A .Z80 file starts off with an 30-byte header- block. In this block, the status of the emulated Z80 processor at the point at which the Z80-emulator was stopped by the user is specified. A few extra environmental variables complete the header. Byte Length Description 0 1 A register 1 1 F register 2 2 BC register pair (LSB, i.e. C, first) 4 2 HL register pair 6 2 Program counter 8 2 Stack pointer 10 1 Interrupt register 11 1 Refresh register (Bit 7 is not significant!) 12 1 Bit 0 : Bit 7 of the R-register Bit 1-3: Border colour Bit 4 : 1=SamRom switched in Bit 5 : 1=Block of data is 'squeezed' Bit 6-7: No meaning 13 2 DE register pair 15 2 BC' register pair 17 2 DE' register pair 19 2 HL' register pair 21 1 A' register 22 1 F' register 23 2 IY register (Again LSB first) 25 2 IX register 27 1 Interrupt flipflop, 0=DI, otherwise EI 28 1 IFF2 (not particularly important...) 29 1 Bit 0-1: Interrupt mode (0, 1 or 2) Bit 2 : 1=Issue 2 emulation Bit 3 : 1=Double interruptfrequency Bit 4-5: 1=High video synchronisation 3=Low video synchronisation 0,2=Normal Bit 6-7: 0=Cursor/Protek/AGF joystick 1=Kempston joystick 2=Sinclair 1 joystick 3=Sinclair 2 joystick After these 30 bytes, a memory dump of the emulated Spectrum follows, consisting of the bytes at address 16384 up to 65535. The first versions of the Spectrum Emulator just dumped the full 48K after the header. These versions therefore produced .Z80 files that were 49182 bytes (=48K + 30 bytes) in length. The sharewareversions of the Emulator all use a slightly different method of storing the 48K datablock, thereby reducing the size of the .Z80 files. In effect, the method consists of finding all sequences of equal bytes, and replacing them by a code of four bytes, "ED ED xx yy" which tells that byte yy is to repeated xx times. An example will make it clear: ED 00 44 ED ED 05 00 02 ... (.Z80 file) is translated back into ED 00 44 00 00 00 00 00 02 ... (Spec-memory) Obviously, only sequences of length at least 4 will be coded, for otherwise there would be no gain in the number of stored bytes. Sequences of 'ED' are treated separately: the minimum length of an 'ED'-sequence to be coded is 2, to avoid problems when translating back. And lastly, if a single 'ED' is encountered, thus an 'ED' followed by a different byte, then this byte following the 'ED' will not be included in a block. This is done to avoid 'ED 00 00 00 00 00' to be translated into 'ED ED ED 05 00' which would not be translated back correctly. This particular sequence of bytes will be coded into 'ED 00 ED ED 04 00'. For a coder-decoder algorithm worked out in 8086-assembly, see the source of CONVZ80. (Only for registered users, of course!) 6. Porting programs There are several ways to port a program from the Spectrum to the PC-environment, where it can be used by the Spectrum Emulator. The simplest way is to load Spectrum programs from tape, see paragraph 4. Sencondly, if you have a Disciple disk interface, you can load all files directly from Disciple disks using a converter program which is supplied with the registered version of the Emulator. If you have an interface I, you can also use the RS232 interface to send the program to the PC. You can use a null-modem cable to connect the Interface-I with the PC. Then: - Type: Z80 /u savespec.bas - Type at the emulated-Spectrum prompt: LOAD *"b" - Type Enter: you'll see a short BASIC-program appear. - Type this program over into a real Spectrum. - RUN it on the real Spectrum. It will generate a short piece of code, which will be saved to tape. - Now load the program you want to download to the PC in the real Spectrum, and stop it. (This might be the most difficult part!) - Type: OPEN #3,"b" on the real Spectrum. - Configure COM1 (or 2, of course) using MODE at 9600,n,8,1. - Type at the DOS-prompt: GETRS filename.Z80 (or: GETRS /2 etc) - LOAD, on the real Spectrum, the short piece of machine-code at any convenient place in the memory. If you don't know where to load it, you can always load it into screen-memory, using LOAD "" CODE 16384. - Type: RANDOMIZE USR 16384 on the real Spectrum. You should see a fast-running counter on the PC-screen. When it reaches 49182, it stops, and after two of three seconds GETRS writes the block of data to disk. - Now type Z80, go to the Main Menu, load the program, go back using option 'T', and start the program using a RUN or a RANDOMIZE USR. If it runs allright, write it back to disk, using the option 'Save program' in the main menu. It will now be packed, occupying less than 49182 bytes on the disk. There is another convenient way to port Spectrum programs to the PC environment, using a program called BDDE with which you can read Beta-disk floppies directly into the PC. BDDE is a shareware program, and is available at many BBS's in the Netherlands, and on the Spectrum Emulator Support BBS, +31-50-264840 1200/2400 bps, between 22.00 and 11.00 local time. <*** End of Summary.Doc ***>