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pseudorandomize LCD/PAL/ITCM/DTCM/MAINMEM for homebrew (previously just pal and LCD was pseuodorandomized)

This commit is contained in:
zeromus 2011-07-03 03:02:27 +00:00
parent b050640b95
commit bbddf0bc24
2 changed files with 33 additions and 21 deletions
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53
desmume/src/NDSSystem.cpp
View File

@ -405,8 +405,12 @@ void GameInfo::populate()
}
}*/
//this may look like a poor heuristic for detecting homebrew, but it is actually pretty good.
//setting your own game code is stupid, so homebrew should just leave it.
//however, non-devkitARM-default makefiles may not have set this.
isHomebrew = !memcmp(header.gameCode,"####",4);
}
#ifdef _WINDOWS
static std::vector<char> buffer;
@ -566,30 +570,11 @@ int NDS_LoadROM(const char *filename, const char *logicalFilename)
INFO("ROM game code: %c%c%c%c\n\n", gameInfo.header.gameCode[0], gameInfo.header.gameCode[1], gameInfo.header.gameCode[2], gameInfo.header.gameCode[3]);
//for homebrew, try auto-patching DLDI. should be benign if there is no DLDI or if it fails
bool isHomebrew = !memcmp(gameInfo.header.gameCode,"####",4);
if(isHomebrew)
if(gameInfo.isHomebrew)
DLDI::tryPatch((void*)gameInfo.romdata, gameInfo.romsize);
NDS_Reset();
//put garbage in vram for homebrew games, to help mimic the situation where libnds does not clear out junk
//which the card's launcher may or may not have left behind
if(isHomebrew)
{
u32 w=100000,x=99,y=117,z=19382173;
for(int i=0;i<sizeof(MMU.ARM9_LCD);i++)
{
u32 t= (x^(x<<11));
x=y;
y=z;
z=w;
t = (w= (w^(w>>19))^(t^(t>>8)));
MMU.ARM9_LCD[i] = t;
if (i<sizeof(MMU.ARM9_VMEM))
MMU.ARM9_VMEM[i] = t;
}
}
memset(buf, 0, MAX_PATH);
path.getpathnoext(path.BATTERY, buf);
@ -2100,6 +2085,32 @@ void NDS_Reset()
MMU_Reset();
//put garbage in vram for homebrew games, to help mimic the situation where libnds does not clear out junk
//which the card's launcher may or may not have left behind
if(gameInfo.isHomebrew)
{
u32 w=100000,x=99,y=117,z=19382173;
CTASSERT(sizeof(MMU.ARM9_LCD) < sizeof(MMU.MAIN_MEM));
CTASSERT(sizeof(MMU.ARM9_VMEM) < sizeof(MMU.MAIN_MEM));
CTASSERT(sizeof(MMU.ARM9_ITCM) < sizeof(MMU.MAIN_MEM));
CTASSERT(sizeof(MMU.ARM9_DTCM) < sizeof(MMU.MAIN_MEM));
for(int i=0;i<sizeof(MMU.MAIN_MEM);i++)
{
u32 t= (x^(x<<11));
x=y;
y=z;
z=w;
t = (w= (w^(w>>19))^(t^(t>>8)));
MMU.MAIN_MEM[i] = t;
if (i<sizeof(MMU.ARM9_LCD)) MMU.ARM9_LCD[i] = t;
if (i<sizeof(MMU.ARM9_VMEM)) MMU.ARM9_VMEM[i] = t;
if (i<sizeof(MMU.ARM9_ITCM)) MMU.ARM9_ITCM[i] = t;
if (i<sizeof(MMU.ARM9_DTCM)) MMU.ARM9_DTCM[i] = t;
}
}
NDS_ARM7.BIOS_loaded = false;
NDS_ARM9.BIOS_loaded = false;
memset(MMU.ARM7_BIOS, 0, sizeof(MMU.ARM7_BIOS));

1
desmume/src/NDSSystem.h
View File

@ -347,6 +347,7 @@ struct GameInfo
u32 mask;
const RomBanner& getRomBanner();
bool hasRomBanner();
bool isHomebrew;
};
typedef struct TSCalInfo