				    XZX-Pro

		       An X11-based ZX Spectrum emulator

		      by Erik Kunze <xzx@zx-spectrum.net>
		      based on XZX 1.0.2 by Des Herriott
				and many others

                 $Id: FAQ,v 4.13 2001/07/15 09:22:15 erik Rel $


Q: Why does the documentation contain so many grammar errors?

A: Because I always write the documentation in a hurry and I am not a language
   expert.  If you want, correct it and send corrected files to me.

Q: I get a "virtual memory exhausted" message during the compilation of z80.c.

A: The file z80.c contains the code for the emulation of the Z80, which itself
   is a huge switch statement.  With optimizations turned on, gcc needs a huge
   amount of memory in order to compile/optimize this code.  Undefine
   HAVE_ENOUGH_SWAP in "config.h" an compile again (this will make the code a
   little slower because it turns parts of the switch statement into separate
   functions, but on a fast machine it should not be noticeable).

Q: I get "xzx: warning: output to 128K/+3 port <fffd> in 48K mode" when running
   the emulator in 48K mode.

A: Your (48k) program accesses ports from the 128K machinery.  There are mostly
   BFFDh and FFFDh (the addresses of the AY sound chip).  Turn off the option
   "warn48".

Q: I have a snapshot whose format is not supported by XZX-Pro.  What can I do
   to load it and run it in XZX-Pro ?

A: Use a snapshot converter, such as SPCONV (which converts to/from almost any
   snap format in existence).  You can download it from the following URIs

   ftp://ftp.void.jump.org/pub/os/sinclair/tools/generic/spconv-110.zip
   ftp://ftp.nvg.unit.no/pub/sinclair/utils/generic/spconv-110.zip.

   Also, you can download the program "zxs2tap" (converter from digital tape
   format ".zxs" to canonical tape format ".tap") from

   http://zx-museum.org.ru/mu/

Q: When I load certain TAP files, they seem to run fine, but sometimes reboot
   the emulator.  What to do ?

A: It's impossible to detect from the TAP file what kind of Spectrum model is
   needed for that file.  Sometimes, you need to load the TAP in 48k
   architecture, some other times in 128k architecture.  For instance, Rick
   Dangerous 2, only runs in 48k, whereas Turrican 2 and Narc only run in 128k
   mode.  Try both and see which works for you.

Q: When I use '-scale 3' is slows down the emulator.  What should I do?

A: If you compiled XZX-Pro without "-DHAVE_ENOUGH_SWAP" then recompile using
   this - if your machine allows it.

   If you are running on a terminal that does not use MIT shared memory then
   try and find one that does.  Note: MIT shared memory is not possible over
   networks.

   Or try to decrease the screen refresh rate step by step until you get
   reasonable speed.  Alternatively, buy a faster video card :-)

Q: The emulator dies immediately with a message like "xzx: error: can't open
   ROM image <spectrum.rom>".

A: Have you installed the application defaults file? Have you installed the ROM
   images with 'make install' ? There are certain resources that are installed
   in the defaults file and which indicate where the ROMs are located : make
   sure you've installed the XZX.ad file and that you've placed the ROMs in the
   right place.

Q: I get a "snapshot uses IF1 but xzx wasn't compiled with IF1 support"
   message when loading a snapshot.

A: You've compiled XZX-Pro without Interface I support.  The person who has
   taken the snap had the Interface I activated.  Your snapshot may or may not
   run under XZX-Pro (your best shot is to recompile XZX-Pro with IF1
   activated).

Q: I've downloaded snapshots from the net and they crash the emulator.

A: This is impossible :-) To be seriously: send me a short problem description
   and the file via email.

Q: Some games, like Video Olympics, do not respond to keyboard input under
   XZX-Pro but do it under xz80.

A: XZX-Pro emulates by standard an Issue 3 Spectrum.  Some older programs need
   an Issue 2 emulation in order to respond to key press.

Q: I exited the emulator, and now the key autorepeat is turned off.

A: XZX-Pro turns of the autorepeat.  If you kill the window from the window
   manager then the exit routine will never be reached and autorepeat will
   remain off.

Q: Some of the function keys do not work.

A: Some window managers like to steal the function keys for its own purposes.
   As long as F10 works then you can pick up any option.

Q: Can I change the emulation speed?

A: Since version 2.7.1 you can set the emulation speed in percent.

Q: I have problems with the keyboard in some snapshots.

A: The snapshot was probably saved with different joystick settings. At this
   time XZX-Pro emulates only a Kempston compatible joystick.

Q: Some programs (Fairlight a Prelude) do not load from a tape file.

A: They check for the original Spectrum ROM and get confused by the traps the
   emulator sets into the ROM.  The only way to get these tapes loaded is to
   remove the traps.  Unfortunately this can only be done on compile time.
   Define 'NO_ED_TRAPS' in config2.h and recompile XZX-Pro.

Q: How does one create disk image from +D disks?

A: This is easy if you use Linux.  A +D disks contains of 80 tracks per side.
   Each track has ten sectors of 512 bytes.  Create a device entry (if not
   already done) with 'mknod /dev/fd0u800 b 2 120' and dump the disk info file
   with 'dd if=/dev/fd0u800 of=image.mgt bs=10k'.
