Aminet 44/Aminet 44 (2001)(GTI - Schatztruhe)[!][Aug 2001].iso/Aminet/docs/mags/TheCrypt17.lha/crypt17/text2/ASP_Review/ASP_Review

Text File | 2001-05-12 | 18KB | 351 lines

@2{AsP (Amiga Spectrum Emulator) v0.78
@6}Programmed by: Ian Greenway

@1*2


                             Distribution: Freeware
@3
                Available from: http://www.greew.freeserve.co.uk
@4
                               Main Requirements:
@5
                     68020 with MMU (Memory Management Unit)
                 2 megabytes of free RAM Workbench/Kickstart 3 +
@6
      MMU   Library   v42   (download   it   from   Ian's  AsP  home  page:
                        http://www.greew.freeserve.co.uk)
@7
      XFD  Package (by Georg Hörmann & Dirk Stöcker) Available from Aminet.
                 Required for loading packed Spectrum programs.
@1
      For  optimum  performance  68040,  33Mhz (or better) with MMU, 32 bit
                                    fast-ram.

*2@5
      Spectrum  ROMS  48K,  128K,  +2  (@1available  from  Ian's  home  page:
      http://www.greew.freeserve.co.uk@5).   These  are freely distributable,
      but are @2©@5 Copyright of Amstrad.

      Reviewed  By:   Craig  '@1Hercules@1'  Daines  (Technical  Editor For@2 THE
      CRYPT@5).

      Ahhh,  the  days of good old 8 bit computing.  I remember my Spectrum
      days  very  well  indeed.   It  was  the  era  of Sinclair User, Your
      Spectrum  (@1later  released  as  Your  Sinclair@5),  the Program Pitstop
      section  in  Your  Sinclair  Magazine  (@1where readers submitted their
      programs  each month@5) and Crash magazine and not forgetting of course
      Marshall  Cavendish's  classic  '@1Input@5'  series  of  magazines  which
      provided  a fascinating insight on writing your own programs in Basic
      and  Z80  assembler.   Those  were the days when you could buy a good
      Speccy game for a meagre £1.99 and still have some pocket money left.
      Unlike today where games software costs the earth.  In the 8 bit days
      of  home  computing, programmers had little available memory to write
      new games, which is why a lot of thought was put into the playability
      of the games (@1unlike today where it's all polygon 3D@5).  They were the
      days of Tim Follin, David Whittaker and Ben Daglish who wrote most of
      the music for computer games during that era....
*2@5
      Some of you may fondly remember the humble ZX Spectrum.  The Sinclair
      ZX  Spectrum  was  devised by Sir Clive Sinclair at Sinclair Research
      back  in  their  radio  days.   Sinclair  revolutionised  the  8  bit
      computing  era by releasing probably one of the first home computers,
      the  ZX80,  which  was  shortly  followed by the ZX81.  Both machines
      featured a monochrome black and white display and a puny 1 KB of RAM,
      but the ZX81 could be expanded to a whopping 16KB via a RAM pack.

      Later,  Sinclair released the appraised ZX Spectrum 16KB, ZX Spectrum
      48K.  Both models complete with a horrid rubber keyboard but with new
      improved graphics, a full sixteen colour palette, a revised BASIC and
      one  channel  beepy  music.   The  rubber  keyboard  issue was latter
      addressed  when  the 48K+ was released (@1which was virtually identical
      to  the keyboard of the Sinclair QL@5).  At long last a Spectrum with a
      decent  keyboard  !   Contrary to belief, Sinclair were serious about
      using their new Sinclair QL as a business machine.

      Many   people   say  the  Amiga  was  the  first  computer  to  offer
      multi-tasking.   @2 WRONG!@5   Sinclair  were  the  first  to  produce  a
      multi-tasking  computer  with  their  release of the Sinclair QL, but
      Commodore  perfected the concept of a multi-tasking OS when the Amiga
      was  introduced  and  exec  was  born  thanks  to  Carl Sassenrath at
      Commodore responsible for writing AmigaOS.  So now you know !
*2@5
      Sadly,  the last Spectrum to be released by Sinclair was the Spectrum
      128K.   This  featured a full 128K of memory, a new 128K Basic, a new
      ROM,  a  3  channel  AY38912  sound microprocessor offering 3 channel
      sound (@1nice although not quite as flexible as Commodore's custom 6581
      Sid chip microprocessor@5).

      The  Spectrum  128K  used to get so hot in use, that Sinclair decided
      upon  fitting  an  external heat-sink to dissipate access heat (@1quite
      nice,  since on those cold winter day's you could warm your hands up,
      or alternatively, fry eggs and bacon on it@5).

      Later,  Alan Sugar at Amstrad bought the rights to the Sinclair range
      of  computers  and came along to save the day:  a Spectrum 128K+2 was
      released.   This  was  identical to Sinclair's 128K model, but with a
      built-in cassette deck and new ROM.

      Despite  all these new Spectrum models, Spectrum users longed to move
      away from the cassette tape.  Third party manufacture's released mini
      tape  streamer's  called  '@1wafer  drives@5' and Miles Gordon Technology
      (@1also  producers of the Sam Coupe computer@5) noticed this niche in the
      market  and  later  released the disciple Plus D.  At around £150 the
      disciple Plus D certainly wasn't cheap.



*2@5
      Amstrad  later  complied  with  an  '@1official@5' Spectrum COMPLETE with
      built  in  disk  drive:  the Spectrum +3.  Amstrad's only pitfall was
      due  to  the fact they choose the silly idea of a 3" disk drive using
      their  own  brand of 3" crapy disks (@1which were expensive at £6-7 per
      disk !@5).  The Spectrum +3 sold fairly well, but then the 8 bit age of
      computing  fazed  out  with arrival of the 16 bit ST and Amiga ranges
      the rest is history...

      Today,  many  people  want  to relive those golden days of computing,
      which  is  why  numerous  Spectrum emulators have been produced for a
      variety of different platforms and OS.

      Many  Spectrum emulators have been developed for the Amiga:  probably
      one  of  the  first  was  the  old KGB Spectrum emulator.  Originally
      programmed  way back in 1990 by an unknown Russian (@1?@5) author, it was
      designed  to  run  on  an old A500 under Kickstart 1.3, and hence was
      painfully slow and bug ridden.



@5
*2      Later   Spectrum  emulators  appeared:   Thanks  to  the  A1200/A4000
      Amiga's, it was possible for developers to code new and fast Spectrum
      emulators  to  run on the Amiga's new 32 bit hardware.  One of my all
      time  favourite emulators was ZXAM.  Originally programmed by Antonio
      J.   Pomar  Roselló,  it  was  probably  one  of  the  first Spectrum
      emulators which offered full emulated 128K sound of the AY38912 sound
      microprocessor.

      ZXAM  still lacked one thing though:  it didn't offer 128K emulation.
      Antonio  had  plans  to  work  on  a 128K version, but due to lack of
      shareware  registrations,  Antonio,  stopped development of ZXAM, and
      then things went into a kind of limbo - Still no ZX Spectrum emulator
      had  been  released for the Amiga which was able to produce @2FULL@5 128K
      emulation at sufficient speed on low powered 32-bit hardware.  As for
      Antonio,  to  this  very  day, he still refuses to give up the source
      code  for  ZXAM...   A  great  irony, since ZXAM was starting to look
      really promising !

      Then  Ian  Greenway  appears.   Ian  spent three years developing ASP
      (@1Amiga Spectrum Emulator@5) which accurately emulates a stock 48K, 128K
      or 128K+2 Spectrum.  As any programmer will tell you, programming any
      software  based  emulator  is no easy feat, especially on the Amiga's
      low  powered  32 bit hardware and a certain degree of resourcefulness
      needs  to  be  taken  into account to ensure the emulation core is as
*2      fast  as  possible and accurate to the Zilog's Z80 microprocessor (@1as
      included  in  a  '@3real@1'  Spectrum@5).  Another key factor is a Spectrum
      emulator  on the Amiga requires for the emulator itself to transcribe
      Z80 instructions into 68k instructions '@1on the fly'@5.

      There  are  other  difficulties  too  when  writing  a  fully-fledged
      Spectrum  128K  emulator:   The  first is emulating the AY38912 sound
      processor  which  was included in Spectrum 128K models.  (@1The AY38912
      was a highly popular choice in the old 8 bit days of micro-computing:
      both  the  Atari  ST  and  Spectrum  models used it for three channel
      sound@5).

      Secondly,  the  original  128K  Spectrum  models  were able to switch
      '@1banks@5' of RAM and ROM in different address areas in memory.  Copying
      the  chunks  of  data  around  under  emulation  isn't  without  it's
      problems,  and  would  slow  things down considerably.  AsP overcomes
      this  with  ease via Thomas 'Thor' Richter's MuMin distribution which
      allows  programmers to do all sorts of wonderful things with your MMU
      via a shared library (@1mmu.library@5).  Ian's emulator uses this to good
      effect  with  dealing  with  all  the horsework of page switching the
      Spectrum's  ROM and RAM banks into different areas in memory (@1as with
      a real 128K Spectrum@5) .  Speed-wize AsP offers fast emulation, and is
      coded in 100% assembler and compiled with DevPac.
*2@5
      AsP  accomplishes  all of this very well indeed, and demonstrates the
      resourcefulness  of  Amiga  developers.   Try  any x86 based Spectrum
      emulator  on  a  PeeCee  and you would need a higher Specification to
      obtain  a  good  emulation  speed (@1probably due to excessive bloat of
      Windows and the awful x86 instruction set@5)

      AsP  relies  upon  a simple Gadtools interface which is small, simple
      and  easy  to use.  The rest of AsP's options are selectable via pull
      down menu's.

      What's  interesting  is  Ian  has also worked on support for graphics
      card  users.   In  fact,  I  found  running  my  Spectrum games via a
      Cybergraphics  v3  screen  was  considerably faster than AGA.  If you
      find  playing your Spectrum games on an AGA screen is painfully slow,
      you can use the BlazeWCP patch (@1available from Aminet@5) which helps to
      speed things up considerably.

      If  you  really want to show off Spectrum emulation at it's best, you
      can  even  play  all  your  old  Spectrum  games  in  a window on the
      Workbench screen.  You'll need a fairly fast machine for this though,
      and  enough  free  pens.   If your Amiga's not overly fast, there's a
      '@1frame  skip@5'  function  which '@1skips@5' subsequent frames.  128K sound

*2      can  be  also  adjusted down to low quality or you can turn it off if
      need be.

      AsP  is  fully OS compliant and opens on it's own screen.  When first
      writing   AsP,   Ian   envisaged  a  non-multi-tasking  emulator  for
      supporting  the  loading of tape-based turboloaders such as the early
      Speedlock  1  (@1as written by David Aubrey Jones and first used on the
      game  '@3Ghostbusters@1'@5),  Speedlock  2,  3, Alcatraz & Firebird loaders
      amongst  others.   Since  CPU  timings  are  critical  if turboloader
      support  was  implemented,  as a result, Ian wouldn't of been able to
      provide  a multi-tasking emulator.  Ian's made the right choice in my
      view  with  producing  a  multi-tasking  emulator anyway.  Note:  You
      could  always  use a multiface cartridge on a '@1real@5' Spectrum to save
      out  a  turboloader  at  normal  speed  and  then load it from a data
      cassette  recorder into Peter McGavin's '@1Spectrum Emulator@5' with an 8
      bit stereo sampling cartridge anyway...

      Joysticks  are  supported as well!  AsP happily emulates the original
      Kempston,  Sinclair Interface 2, Cursor joystick and also custom keys
      may  be defined to simulate a joystick.  There are some problems with
      regard  to Kempston Joystick emulation with some games, so a Kempston
      '@1Smart@5' Joystick option has been implemented.
*2@5      Directory  Opus  users  aren't left out either.  I suggested to Ian a
      number  of  ideas  and  as a result he has implemented a filetype for
      Opus fans.

      I've  tested @2A LOT@5 of Spectrum software from Epic's Speecy '97 CD-ROM
      with  AsP.   The  only  game which seems to have problems seems to be
      Ocean's  '@1Where  Time  Stood  Still@5'.   Ian  informs  me  the game is
      somewhat  processor  intensive.  Hopefully once he begins work on the
      dynamic  JIT  emulation  core,  I can finally look forward to playing
      this  game for the first time in over 10 years (@1I always use to laugh
      when  Fat Clive used to get stuck in the hole of the bridge@5). @2 Laughs
      out Loud@5 !

      By  default,  AsP  open's  an  ARexx port called '@1AsP_0@5'.  If you run
      multiple  versions of AsP simultaneously another Arexx port is opened
      called  '@1AsP_1@5'.   ARexx  scripts are included for loading and saving
      Spectrum  screen  images  (@1commonly  referred  to as SCREEN$@5):  These
      start  at  address  16384  and  have  a  total  length of 6912 bytes.
      Datatypes  are  available from Aminet for reading these on the Amiga,
      so   any   saved   Spectrum   '@1SCREEN$@5'  may  be  saved  out  as  IFF
      (@1interchangeable  file  format@5)  for  printing  or  editing  in  your
      favourite  art  package.  Ian's also includes a separate ARexx script
      for  entering  Multiface  pokes  to input pokes for infinite lives or

*2      energy on your favourite Spectrum games.  This works well.  The ARexx
      support  is clearly explained in AsP's documentation for those of you
      who want to have fun writing your own Arexx's scripts.

      The  supplied ARexx script for entering multiface pokes is great, but
      searching for infinite lives/energy yourself is not possible.  What's
      needed is a built-in life finder.  Hopefully, Ian will implement this
      soon  in  the  next release.  Hence, I've been using the Amos written
      '@3Lifeshield@5'  (@1available  from  Aminet@5)  for  searching  for infinite
      energy/lives with my Speccy games.

      A  whole  range  of  different  Spectrum formats are supported by AsP
      including:-
@4
      Z80:@1
      ----@5
      The  Z80  format  was devised for Spectrum emulators developed on IBM
      PC's and compatables as well as Apple Macintosh.  These include:

@1      -@5 G.A.Lunter, PC, Netherlands.

@1      -@5 SPECTATOR, Carlo Delhez, QL, Netherlands.

*2@1      -@5 Ergon developments emulators, QL, Italy.

@1      -@5 ZX, Andrew Lavrov, QL.

@1      -@5 Mac Spectacle, Guenter Woigk, Germany, 19.

@1      -@5 ZXAM, Antonio J. Pomar Rosselló, Amiga, Spain.

@4
      Mirage .SNA and .snapshot type:@1
      -------------------------------@5
@1      - @5Spectrum, Peter McGavin, Amiga, New Zealand.

@1      - @5JPP, Arnt Gulbrandsen, PC, Norway.

@1      - @5ZXAM Antonio J. Pomar Rosselló, Amiga, Spain.
@4
      TAP:@1
      ----@5
      The TAP format is used by many different types of Spectrum emulators.
      It  is  similar to a saved program on Spectrum cassette.  AsP handles
      these, as does ZXAM.





*2@4
      The Verdict:@1
      ------------@5
      If you have happy memories of the early days of Spectrum computing, I
      suggest   you   visit   Ian's   AsP  homepage  to  download  AsP  at:
@3      www.greew.freeserve.co.uk@5

      Ian  welcomes  any  comments,  suggestions and bug reports, so if you
      have any idea's on what you would like to see implemented, drop him a
      line  at: @3 [e-mail].@5  Please bear in mind, if you have any
      ideas  you  would  like to see implemented, be sure to check that Ian
      doesn't  already  have  plans  to  incorporate it in future versions.
      Also,  don't  mention  '@1Where  Time  Stood  Still@5' still doesn't work
      properly:    Ian's  been  plagued  by  many  people  mentioning  this
      (@1including myself@5)








*2
      Considering  what  Ian's managed to achieved to on the Amiga aging 32
      bit  hardware,  AsP is clearly the fastest and best Spectrum emulator
      available  for the Amiga today, and what's more, it's freeware !  Ian
      still has further plans to develop his emulator including:-

      A status line.
      Native-only (faster) display.
      More ARexx commands.
      Auto cheat-finder/poker.
      IFF screen grab.
      TZX file loading.
      TAP file saving.
      Dynamic JIT compiling emulation core.
      More snapshot formats.
      Disk format support.

      If you would like to know more on how Ian has developed his emulator,
      check out '@1AsP Spectrum Emulator@5' - an interview with Ian Greenway in
      this edition of @2THE CRYPT@5.




*2
      As  for  those  of  you who want to get your hands on virtually every
      classic  Spectrum  game  ever  released,  why not purchase the Speccy
      98/99  CD-ROM's  which  can  be purchased from '@1Weird Science@5' at the
      bargain  price  of  £4.99 each.  Postage for one CD-ROM is £1 and 50p
      thereafter.    When  ordering  software  from  our  sponsors,  please
      telephone  prior  to ordering to check stocks and availability and be
      sure  to  mention  you  saw  their product catalogue in @2THE CRYPT@5. To
      place  your  order  for either the Speccy '98 or Speccy '99 CD-ROM's,
      telephone @1Weird Science@5 on:  [phone].

      Long live the Speccy (@1and emulation@5) !
@7
      Craig Daines@5
      Technical Editor For @2THE CRYPT@3
      [e-mail]