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remove memory randomization for homebrew. this ended up being a bad idea for a number of reasons. it wont return until it is made optional.

This commit is contained in:
zeromus 2011-08-25 20:31:19 +00:00
parent 35b32046e9
commit d849bf11db
1 changed files with 28 additions and 22 deletions
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50
desmume/src/NDSSystem.cpp
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@ -43,6 +43,7 @@
#include "path.h"
//int xxctr=0;
//#define LOG_ARM9
//#define LOG_ARM7
//bool dolog = false;
@ -2084,29 +2085,34 @@ void NDS_Reset()
MMU_Reset();
//put garbage in vram for homebrew games, to help mimic the situation where libnds does not clear out junk
//put random 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;
}
}
//1. retail games dont clear TCM, so why should we jumble it and expect homebrew to clear it?
//2. some retail games _dont boot_ if main memory is jumbled. wha...?
//3. clearing this is not as useful as tracking uninitialized reads in dev+ builds
//4. the vram clearing causes lots of graphical corruptions in badly coded homebrews. this reduces compatibility substantially
//conclusion: disable it for now and bring it back as an option
//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;