On Tue, 20 Jul 1999 20:47:08 +0200, Laurens Holst wrote:
>> >I bet the Z380 has a good counterpart for MULUW and MULUB...
>> It has multiplication instructions, but I don't know if they're exactly
>> the same.
>Mwa... I think so. Only other opcode I think.
I do not remember that, but Z380 have a lot of MULT instructions...
And even DIV instructions... (-:
>No, no, in contrary. It's quite easy. First, all those instructions have
>multi-byte opcode, don't they? Do the chance you get something wrong is
>already minimized. Second, you can look at the byte before it. If it's the
>opcode of an LD HL,nn-like instruction the it probably won't be the
>instruction you're looking for (unless the programmer used 'nested'
>instructions, which is not used often though, only in BIOSses). Next, you
>can show the surrounding code and if it makes sense, then it's a REAL
>multiplication-instruction. If it doesn't, it's probably data. It might even
>be possible to let a program automatically decide if the surrounding data is
>code...
>Also, I don't know what the opcode is, but I think it's not a simple one, so
>it's highly inlikely that the opcode will be (referred to as) data.
Believe me... It's impossible do this. (-: There is the need of a pre-processor
that knows all opcodes of R800 and, when turned on, will act just like the R800,
but will interpret the R800 only opcodes and pass to Z380 the common opcodes.
This pre-processor would be almost a full processor.
>> Turbo R ST doesn't have MIDI, only GT has. So I guess Illusion City can do
>> without. I'm not sure if it uses PCM, I played for only a little while.
>Oh. Well, Daniel says it did.
I'm not sure of that... (-: But I think it uses. MIDI it will not use as a need,
because it
is not on ST... But PCM is standard on both ST and GT. So, it's strange think in
a program for TR that not uses it... It would be like an MSX2+ program that
uses V9938 and doesn't make use of FM... (-:
I saw Illusion City only one time, and I see it before Fray TR... I remember that
FrayTR uses PCM to reproduce voices... But I'm not sure if Illusion City has voices...
>Yeah, okay, that's cool. But not the OPL4-way, because the OPL4 sampleunit
>really SUCKS!!! It can play nice samples but there are three disadvantages:
>1. The sample always has to loop at the end, you can't just let it stop.
Really? Yuck! /-:
>2. Therefor, the OPL4 can't generate an interrupt if the sample is finished,
This is not really bad, but would be usefull...
>3. You can't play sound and access the SampleRAM at the same time.
>Resulting in a maximum sample-length of 64k (using an 8-bit sample).
>Therefor, the OPL4 is, although it supports high frequency, high quality
>samples (16 bit, 44.1kHz), definately NOT FIT to play large samples like
>.WAV-files.
Look, OPL4 is not a PCM Player. OPL4 is a WaveTable... (-: And WaveTables
are not made to play PCM sounds (like WAVs). It's very important to
exist a WaveTable AND a PCM unit.
>It would be the best if you could tell the sampling-device to generate an
>interrupt at byte X, therefor enabling the program to start filling the
>SampleRAM again a short while before it runs out of SampleRAM (although this
>is not a nice solution, because it could result in problems on future
>too-fast MSX computers... But let's not assume this). Also, the presence of
>this device would make it possible for game-developers to support sampled
>soundeffects for the non-MoonSound users.
I think it would be nice if the interruptions of sound were interpreted into the
sound board... I really don't like interruptions on the main processor. (-:
>Ah, and by the way, MSX-programmers should in the future avoid to develop
>speed-sensitive programs. What I'm trying to say is for example in case of a
>screensplit: try not to assume it arrived at a certain line after some
>initializations before the real lineinterrupt, but keep track of the amount
>of H_BLANKs, even if this makes you to put the screensplit a few 'lines'
>higher.
Like some video games does...?
[]'s Daniel Caetano
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