From bf643fd9c59939266ee95021292a08b5d20a250e Mon Sep 17 00:00:00 2001 From: gameblabla Date: Sun, 21 Jul 2019 05:39:55 +0200 Subject: [PATCH] psxbios: Some games read from address 0, fix that. See Garbage Area at Address 00000000h in Nocash PSX Specifications for more inf> R-types will refuse to boot if psxM[0] is zero. Fade to Black can crash upon memory card access if psxM[5] is set to the wrong > Crash Team Racing will refuse to boot if psxM[2] and psxM[3] are not zero. (Previously, that region of memory would be overwritten above. No explanation why.) It's set as such according to nocash : [00000000h]=3C1A0000h ;<-- but overwritten by 00000003h after soon [00000004h]=275A0C80h ;<-- or 275A0C50h (in older BIOS) [00000008h]=03400008h [0000000Ch]=00000000h Note that setting 00000000h to 00000003h doesn't work for R-types. --- libpcsxcore/psxbios.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/libpcsxcore/psxbios.c b/libpcsxcore/psxbios.c index ca159431..7b2c05fc 100644 --- a/libpcsxcore/psxbios.c +++ b/libpcsxcore/psxbios.c @@ -3052,7 +3052,9 @@ void psxBiosInit() { */ // opcode HLE psxRu32ref(0x0000) = SWAPu32((0x3b << 26) | 4); - psxMu32ref(0x0000) = SWAPu32((0x3b << 26) | 0); + /* Whatever this does, it actually breaks CTR, even without the uninitiliazed memory patch. + Normally games shouldn't read from address 0 yet they do. See explanation below in details. */ + //psxMu32ref(0x0000) = SWAPu32((0x3b << 26) | 0); psxMu32ref(0x00a0) = SWAPu32((0x3b << 26) | 1); psxMu32ref(0x00b0) = SWAPu32((0x3b << 26) | 2); psxMu32ref(0x00c0) = SWAPu32((0x3b << 26) | 3); @@ -3078,6 +3080,21 @@ void psxBiosInit() { psxHu32ref(0x1060) = SWAPu32(0x00000b88); hleSoftCall = FALSE; + + /* Some games like R-Types, CTR, Fade to Black read from adress 0x00000000 due to uninitialized pointers. + See Garbage Area at Address 00000000h in Nocash PSX Specfications for more information. + R-type will work if PsxM[0] is non-zero. (Meaning that it should not be 00000003h as he implies). + Crash Team Racing will refuse to boot if psxM[2] and psx[3] are not set to 0. + Fade to Black can crash upon memory card access if byte 5 is set to the wrong value. + */ + psxM[0] = SWAPu32(0x3C); + psxM[1] = SWAPu32(0x1A); + psxM[2] = SWAPu32(0x00); + psxM[3] = SWAPu32(0x00); + psxM[4] = SWAPu32(0x27); + psxM[5] = SWAPu32(0x5A); + psxM[6] = SWAPu32(0x0C); + psxM[7] = SWAPu32(0x80); } void psxBiosShutdown() { -- 2.39.2