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(MESS) Fix GD-Rom booting in DC US and PAL [PsyMan]

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This commit is contained in:
Angelo Salese 2013-08-26 13:47:01 +00:00
parent 05dad0b0e3
commit 544546210b
3 changed files with 60 additions and 1 deletions
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3
src/mame/includes/dc.h
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@ -163,6 +163,9 @@ class dc_state : public driver_device
#define SB_G1SYSM ((0x005f74b0-0x005f7400)/4)
#define SB_G1CRDYC ((0x005f74b4-0x005f7400)/4)
#define SB_GDAPRO ((0x005f74b8-0x005f7400)/4)
/*-------- Unknown/Special Registers ---------*/
#define GD_UNLOCK ((0x005f74e4-0x005f7400)/4)
/*---------- GD-DMA Debug Registers ------------*/
#define SB_GDSTARD ((0x005f74f4-0x005f7400)/4)
#define SB_GDLEND ((0x005f74f8-0x005f7400)/4)

50
src/mess/drivers/dccons.c
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@ -400,6 +400,54 @@ static MACHINE_CONFIG_START( dc, dc_cons_state )
MCFG_DEVICE_ADD("cdrom", GDROM, 0)
MACHINE_CONFIG_END
/*
PsyMan notes:
Here's a basic report on the Dreamcast boot files used in MAME (BIOS+Flash pairs):
-----
"dc101d_us.bin", 0x000000, 0x200000, CRC(89f2b1a1) SHA1(8951d1bb219ab2ff8583033d2119c899cc81f18c) ) // BIOS
This is a proper European and USA BIOS. It's even possible that it was used at a later point for Japanese systems.
It only has minor differences compared to BIOS 1.01c.
"dcus_ntsc.bin", 0x000000, 0x020000, BAD_DUMP CRC(c611b498) SHA1(94d44d7f9529ec1642ba3771ed3c5f756d5bc872) ) // Flash
Checking at 0x0001A000 and the mirrored data at 0x0001A0A0 gives away that this is hacked from a PAL/European flash file.
The broadcast (0x0001A004) is also set at 50Hz which is a PAL standard.
"dc101d_eu.bin", 0x000000, 0x200000, CRC(a2564fad) SHA1(edc5d3d70a93c935703d26119b37731fd317d2bf),ROM_BIOS(1)) // BIOS
This BIOS has Chinese language added. So either this is a bad BIOS or Dreamcast was actually officially released there.
"dc101c_eu.bin", 0x000000, 0x200000, CRC(2f551bc5) SHA1(1ede8d5be49116a4c6f3fe0961175469537a0434),ROM_BIOS(2)) // BIOS
This seems to be a proper European and USA BIOS. It's even possible that it was used at a later point for Japanese systems.
It only has minor differences compared to BIOS 1.01d.
"dceu_pal.bin", 0x000000, 0x020000, BAD_DUMP CRC(b7e5aeeb) SHA1(11e02433e13b793ec7ffe0ae2356750bb8a575b4) ) // Flash
This appears to be a valid PAL/European flash. It's unknown if the data at 0x0001A0A0 (from 0x0001A000) should be mirrored there.
Maybe a game does this mirroring or maybe it's there by default. It's certain that some games wrote to this flash though.
"dc1004jp.bin", 0x000000, 0x200000, CRC(5454841f) SHA1(1ea132c0fbbf07ef76789eadc07908045c089bd6) ) // BIOS
This seems to be a proper Japanese BIOS. This BIOS was used at least by early Japanese Dreamcast models.
Code-wise, it has major differences compared to later BIOS versions.
"dcjp_ntsc.bin", 0x000000, 0x020000, CRC(5F92BF76) SHA1(BE78B834F512AB2CF3D67B96E377C9F3093FF82A) ) // Flash
Checking at 0x0001A000 and the mirrored data at 0x0001A0A0 gives away that this is hacked from a PAL/European flash file.
The broadcast (0x0001A004) is also set at 50Hz which is a PAL standard.
-----
From all the aforementioned files the only personally verified one is "dc101d_us.bin", CRC(89f2b1a1).
The resulting file was dumped twice, once from an NTSC/USA system and once from a PAL/EUR system. Both files had a side by side byte match.
*/
ROM_START(dc)
ROM_REGION(0x200000, "maincpu", 0)
ROM_LOAD( "dc101d_us.bin", 0x000000, 0x200000, CRC(89f2b1a1) SHA1(8951d1bb219ab2ff8583033d2119c899cc81f18c) ) // BIOS
@ -425,7 +473,7 @@ ROM_START( dcjp )
ROM_REGION(0x020000, "dcflash", 0)
/* ROM_LOAD( "dcjp_ntsc.bad", 0x000000, 0x020000, BAD_DUMP CRC(307a7035) SHA1(1411423a9d071340ea52c56e19c1aafc4e1309ee) ) // Hacked Flash */
ROM_LOAD( "dcjp_ntsc.bin", 0x000000, 0x020000, CRC(5F92BF76) SHA1(BE78B834F512AB2CF3D67B96E377C9F3093FF82A) ) // Flash
ROM_LOAD( "dcjp_ntsc.bin", 0x000000, 0x020000, BAD_DUMP CRC(5F92BF76) SHA1(BE78B834F512AB2CF3D67B96E377C9F3093FF82A) ) // Flash
ROM_END
ROM_START( dcdev )

8
src/mess/machine/dccons.c
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@ -743,5 +743,13 @@ WRITE32_MEMBER(dc_cons_state::dc_mess_g1_ctrl_w )
atapi_regs[ATAPI_REG_SAMTAG] = GDROM_PAUSE_STATE | 0x80;
}
break;
// The following is required to unlock the GD-ROM. The original Japanese BIOS doen't need it
case GD_UNLOCK:
if (data==0 || data==0x001fffff || data==0x42fe)
{
atapi_regs[ATAPI_REG_SAMTAG] = GDROM_PAUSE_STATE | 0x80;
printf("Unlocking GD-ROM! %x\n", data);
}
break;
}
}