Snatcher ACT 3 for MSX 2

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By Grauw

Ascended (9666)

Grauw's picture

20-02-2021, 14:09

TheKid wrote:

Okay, didn”t know that. But why does a memory mapper not help? Do these machines need a special one?

Does the code read from I/O ports FCH to FFH? Because that’s not allowed, and will break.

By TheKid

Paragon (1102)

TheKid's picture

20-02-2021, 13:09

I don”t know. I use the .bin driver provided with scc blaffer nt to load sbm and sbk file in basic.

By Grauw

Ascended (9666)

Grauw's picture

20-02-2021, 13:45

A brief look at BNTPLAY.ASM shows this, and similar code in RepInt.start;

SetMemory:
	in a,($fd)
	ld (Map1.org),a

	in a,($fe)
	ld (Map2.org),a

	in a,($a8)
	ld (pr.org),a

	ld a,($ffff)
	cpl
	ld (sec.org),a

	di

	ld a,(pr.set)
	out ($a8),a

	ld a,(sec.set)
	ld ($ffff),a

	ei

	ret

Definitely this is the problem. The SCC Blaffer NT replayer reads from the mapper ports (illegal), and it seems the secondary slot mechanism is misunderstood as well, so that can also cause problems.

Compatibility issues were noted before, see the comments here:

https://www.msx.org/downloads/music/trackers/scc-blaffer-nt-13

The solution is to replace all direct slot I/O (in/out ($a8) and ld ($ffff)) with BIOS routine calls, and to replace all the mapper reads (in a,($fc-$ff)) with reads from mirror addresses (initialised to 3 2 1 0), and write to those mirrors whenever outing to the mapper ports. If DOS2 support is also wanted, the mapper port I/O needs to be replaced with calls to the extended BIOS routines.

By AxelF

Champion (374)

AxelF's picture

20-02-2021, 14:16

Twitch streamer ANNK_ gives Snatcher ACT 3 for MSX 2 a (7 out of 10), well done TheKid.
https://www.twitch.tv/videos/918515900?t=2h18m50s

By TheKid

Paragon (1102)

TheKid's picture

20-02-2021, 16:36

Nice, that’s way more then they give our 90’s website Smile Smile

By TheKid

Paragon (1102)

TheKid's picture

20-02-2021, 19:30

@grauw: Okay so the driver needs an update Smile

By Manuel

Ascended (17674)

Manuel's picture

20-02-2021, 21:51

Who wrote that music?

By TheKid

Paragon (1102)

TheKid's picture

21-02-2021, 08:46

We did with huge help,of meits.

By Meits

Scribe (6327)

Meits's picture

21-02-2021, 15:46

You made the music, I corrected a few wrong notes Wink

By TheKid

Paragon (1102)

TheKid's picture

21-02-2021, 16:27

And corrcted some songs to fit better in the tempo. But don’t be modest, you’ve put in quite some time which was much appriciated Smile Smile

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