CAESAR Logo

Catalogue of Arcade Emulation Software - the Absolute Reference

Valid XHTML 1.0! Valid CSS!

X-Arcade

X-Arcade

Large CAESAR Logo

megasys1.c

0.35b4 [Luca Elia]


TODO:

- There's a 512 byte PROM in the video section (different for every game) that controls the priorities. It's been dumped for only a few games, so we have to use fake data for the missing ones.

- Making the M6295 status register return 0 fixes the music tempo in avspirit, 64street, astyanax etc. but makes most of the effects in hachoo disappear! Define SOUND_HACK to 0 to turn this hack off. This seems to be some Jaleco magic at work (strange protection?). The bootleg version of rodlandj has one instruction patched out to do exactly the same thing that we are doing (ignoring the 6295 status).

- Iganinju doesn't work properly: I have to patch lev3 irq and it severely slows down at times. Strangely, it gets *better* by lowering the main CPU clock from 12 to 7 MHz. This is likely an interrupt timing issue: changing the order in interrupt_A() from 3 2 1 to 1 2 3 makes it work reasonably well for a very short while.

- VERY bad sprite lag in iganinju and plusalph and generally others. Is this a sprites buffer issue ?

- Understand a handful of unknown bits in video regs

- English version of Iga Ninjyutsuden called "Kazan" not dumped yet.


SERVICE MODE:

- To enter service mode in some games press service1 + F3.


NOTES:

- MAME use a SOUND_HACK to fix tempo and samples in at least avsprit, 64street and astyanax. But will break at least one game: hachoo.


VIDEO HARDWARE NOTES:

- The Jaleco Mega System 1 has 3 scrolling layers (Note: MS1-Z has 2 layers only). A page is 256x256, approximately the visible screen size. Each layer is made up of 8 pages (8x8 tiles) or 32 pages (16x16 tiles). The number of horizontal pages and the tiles size is selectable, using the layer's control register. I think that when tiles are 16x16 a layer can be made of 16x2, 8x4, 4x8 or 2x16 pages (see below). When tile size is 8x8 we have two examples to guide the choice:


Bugs:

- chimerab: no movements in attract mode / instruction screen, cybattlr: you can play in attract mode (play for free! :P) and 64street: characters don't move in attract mode. megasys1c070u5gre Y.M.I / [MK]


WIP:

- 0.106u3: Massive dipswitch update to the MegaSystem1 driver [Brian Troha, Guru, Yasuhiro Ogawa].

- 0.105u3: Twisty fixed/improved dipswitches in the MegaSystem1 driver.

- 0.99u9: Aaron Giles removed tilemap_dispose call and fixed the two drivers that were using it. This fixes improper save state registrations in megasys1 and namcond1/ygv608 games.

- 0.91: David Haywood increased interleave in MegaSystem1 driver.

- 0.89u1: R. Belmont fixed MSM6295 stereo sound in Jaleco MegaSystem1 games.

- 0.85u1: Mamesick fixed input port definition errors in the Mega System 1 driver.

- 0.84u5: Mamesick fixed input ports in the Mega System 1 driver.

- 20th February 2002: R. Belmont submitted a fix to Jaleco Mega System 1 sound to remove a hack from the sound hardware.

- 0.37b14: Changed clock speed of the 2x OKI6295 to 30303 Hz.

- 22nd May 2001: Luca Elia added Jitsuryoku!! Pro Yakyuu to the Mega System 1 driver.

- 27th September 2000: Luca Elia added stereo sound support to Jaleco Mega System 1 games.

- 11th February 2000: Luca Elia added Takeda Shingen to the Mega System 1 driver.

- 10th January 2000: Luca Elia added Soldam to the Mega System 1 driver and fixed some bugs.

- 0.36b9: Luca Elia added megasys1.h. This file contains definitions used across multiple megasys1 and non megasys1 Jaleco games.

- 8th November 1999: Luca Elia added Kick Off to the Mega System 1 driver.

- 4th November 1999: Luca Elia added Big Striker to the Mega System 1 driver.

- 0.36b7: Several improvements to FM sound emulators. This also fixes crashes in some Jaleco Mega System 1 games [Tatsuyuki Satoh].

- 10th October 1999: Nicola fixed some crashing bugs in the Mega System 1 driver.

- 8th October 1999: Luca Elia fixed sent in a huge Mega System 1 update with many fixes and new drivers for Chimera Beast, Iga Ninjyutsuden, Plus Alpha and Peek-a-Boo!

- 22nd September 1999: Brad Oliver fixed Jaleco Mega System 1 from trashing memory so badly.

- 31st March 1999: Luca Elia sent in a huge update to the Jaleco Mega System 1 driver, with support for Rodland (Japan version only), Earth Defense Force and Avenging Spirit.

- 0.35b4: Added megasys1.c driver. TODO: Support encrypted games. Understand an handful of unknown bits in video regs. Flip Screen support.

- 24th February 1999: Luca Elia has added Legend of Makaj and P-47 USA to the Jaleco Mega System 1 driver.

- 19th February 1999: Luca Elia has made a Jaleco Mega System 1 driver, but currently only P-47 (Jap) and 64th Street are supported.