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Jimbo
Lemon64 Donator!
Lemon64 Donator!


Joined: 25 Jan 2002
Posts: 221
Location: UK

PostPosted: Tue Jun 04, 2002 5:04 pm    Post subject: Questions...Questions Reply with quote

OK Chaps I'm off back to work in Hampshire tommorrow so no Lemon connection for me for a while.
Can any-one answer the following questions?

1 : In Winvice what does true drive emulation actually do ?

2 : Why can't I load game snapshots I have made? (Damm thing just freezes up!)

3 : Recently completed Wizball, what is the end screen all about ?

Well there you go, see you all in a few weeks.

Jimbo... Question
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bacon
C64 Games Programmer
C64 Games Programmer


Joined: 15 May 2002
Age: 43
Posts: 497
Location: Sweden, Gothenburg

PostPosted: Tue Jun 04, 2002 6:08 pm    Post subject: Reply with quote

I could answer the first question like this:

RTFM!

But I'm a nice guy, so I'll give you this excerpt from the manual instead (where it says "hardware level emyulation", it's the same as "true drive emulation"):

Quote:
When using disk images there are two available types of drive emulation. One of them the DOS level drive emulation. It does not really emulate the serial line, but patches the kernal ROM (with the so-called kernal traps) so that serial line operations can be emulated via C language routines. This emulation is very fast, but only allows use of standard DOS functions (and not even all of them). The IEEE488 drives (2031, 2040, 3040, 4040, 1001, 8050 and 8250) do not use kernal traps. Instead the IEEE488 interface lines are monitored and the data is passed to the drive emulation. To use them on the C64, you need to enable the IEEE488 interface emulation. Only if the IEEE488 emulation is enabled, those drives can be selected.

The other alternative is a hardware level drive emulation. The Commodore disk drives are provided with their own CPU (a 6502 as the VIC20 and the PETs) and their own RAM and ROM. So, in order to more closely emulate its features, a complete emulation of this hardware must be provided and that is what the hardware level emulation does. When the hardware level emulation is used, the kernal routines are remain unpatched and the serial line is fully emulated. The problem with this emulation is that it needs a lot of processing power, mainly because the emulator has to emulate two CPUs instead of one.


What this means is that some programs that rely on special features of the 1541 drive will not work without true drive emulation (this is true for some copy-protected software).
The other two questions I leave for someone else to answer.
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Das rubbernecken Sichtseeren keepen das cotton-pickenen Hands in die Pockets muss; relaxen und watschen die Blinkenlichten.
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Sokratekk
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Joined: 28 Jan 2002
Posts: 433
Location: Germany

PostPosted: Thu Jun 06, 2002 9:03 am    Post subject: Reply with quote

to answer your third question:

after you have painted the last level, you can see 3 levels in a 3-d view, flashing in various coulors. Wizcat is screaming like hell... and after 10 second the game starts again with a grey level 1 but with stronger enemys.
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