Metal Gear 2 and King's Valley 2 patches updated

by sd_snatcher on 16-07-2011, 00:04
Topic: Software
Languages:

Brazilian MSX game expert sd_snatcher has updated two of his previous patches for Metal Gear 2 and King's Valley 2. Fixes in these versions:

Metal Gear 2

  • Support for warmboot. This way you can just load the ROM under MSX-DOS2 using your preferred megaROM emulator and the savegames will load/save on your harddisk
  • The jukebox routines were fixed and now pass the MSX Acid2Test
  • Fixed a routine on boot that caused problems on generic megaROM emulator hardware, like the megaRAM
  • The turbo isn't enabled for the Panasonic MSX2+ machines anymore, since the PSG frequencies get 50% higher when the turbo is enabled on those machines. In other words, the sound gets distorted

King's Valley 2 MSX2

  • Fixed a bug that caused problems when the game was run under MSX-DOS2

Relevant link: FRS

Comments (5)

By NYYRIKKI

Enlighted (5396)

NYYRIKKI's picture

16-07-2011, 02:22

•The turbo isn't enabled for the Panasonic MSX2+ machines anymore, since the PSG frequencies get 50% higher when the turbo enabled on those machines. In other words, the sound gets distorded.

Correct fix would have been modifying PSG-routines to play one octave down. Tongue

By Paulbrk

Hero (611)

Paulbrk's picture

18-07-2011, 19:32

Yeah, I think that the best way to fix the bug in the Turbo for MSX2+ is not eliminate the turbo itself, its to down the PSG values until it gets right Big smile

By sd_snatcher

Prophet (3092)

sd_snatcher's picture

18-07-2011, 21:19

It's fun as a joke, but the truth is that he PSG pitch shouldn't be affected by the turbo. That's a hardware design mistake that can't be fixed by software, because different clock speeds result in different pitches. The software can never be sure of how much the sound is out of tune. Smile

It's a matter that must be fixed by hardware. The same applies to the SCC and OPL sound cartridges: they should include their own crystal and not use the CPUCLK signal as a sound reference. Just like any ISA sound card was designed.

Curiously enough, the MSX-Music of those Panasonic MSX2+ was designed correctly: It's sound pitch isn't affected by the turbo.

By Paulbrk

Hero (611)

Paulbrk's picture

19-07-2011, 10:27

But, I have MegaFlash SCC+ 1MB, the SCC and PSG are implemented on a FPGA, the sound of the internal PSG is deactivated and only sound on the Cartrige, that is why I didn't notice of the pich, because the both SCC and PSG sounds in the cartridge.

You should put the two versions of the patch, the latest and the other one.

Turbo and sound works perfect on my Panasonic MSX2+ with Pazos MegaFlashRom SCC+ 1MB.

By sd_snatcher

Prophet (3092)

sd_snatcher's picture

19-07-2011, 14:05

@Paulbrk

Let's move this conversation to this forum thread so I can track it easier.