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fix r3643 regression which broke arm7 on certain bios configurations due to bug in the bios protection check

This commit is contained in:
zeromus 2010-05-17 19:22:34 +00:00
parent 40d58e14fc
commit 37453c7af9
2 changed files with 9 additions and 2 deletions
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3
desmume/src/MMU.cpp
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@ -4106,6 +4106,9 @@ u8 FASTCALL _MMU_ARM7_read08(u32 adr)
{ {
//u32 prot = T1ReadLong_guaranteedAligned(MMU.MMU_MEM[ARMCPU_ARM7][0x40], 0x04000308 & MMU.MMU_MASK[ARMCPU_ARM7][0x40]); //u32 prot = T1ReadLong_guaranteedAligned(MMU.MMU_MEM[ARMCPU_ARM7][0x40], 0x04000308 & MMU.MMU_MASK[ARMCPU_ARM7][0x40]);
//if (prot) INFO("MMU7 read 08 at 0x%08X (PC 0x%08X) BIOSPROT address 0x%08X\n", adr, NDS_ARM7.R[15], prot); //if (prot) INFO("MMU7 read 08 at 0x%08X (PC 0x%08X) BIOSPROT address 0x%08X\n", adr, NDS_ARM7.R[15], prot);
//How accurate is this? our R[15] may not be exactly what the hardware uses (may use something less by up to 0x08)
//This may be inaccurate at the very edge cases.
if (NDS_ARM7.R[15] > 0x3FFF) if (NDS_ARM7.R[15] > 0x3FFF)
return 0xFF; return 0xFF;
} }

8
desmume/src/armcpu.cpp
View File

@ -395,10 +395,12 @@ FORCEINLINE static u32 armcpu_prefetch()
// } // }
//#else //#else
curInstruction &= 0xFFFFFFFC; //please don't change this to 0x0FFFFFFC -- the NDS will happily run on 0xF******* addresses all day long curInstruction &= 0xFFFFFFFC; //please don't change this to 0x0FFFFFFC -- the NDS will happily run on 0xF******* addresses all day long
armcpu->instruction = _MMU_read32<PROCNUM, MMU_AT_CODE>(curInstruction); //please note that we must setup R[15] before reading the instruction since there is a protection
//which prevents PC > 0x3FFF from reading the bios region
armcpu->instruct_adr = curInstruction; armcpu->instruct_adr = curInstruction;
armcpu->next_instruction = curInstruction + 4; armcpu->next_instruction = curInstruction + 4;
armcpu->R[15] = curInstruction + 8; armcpu->R[15] = curInstruction + 8;
armcpu->instruction = _MMU_read32<PROCNUM, MMU_AT_CODE>(curInstruction);
//#endif //#endif
return MMU_codeFetchCycles<PROCNUM,32>(curInstruction); return MMU_codeFetchCycles<PROCNUM,32>(curInstruction);
@ -417,10 +419,12 @@ FORCEINLINE static u32 armcpu_prefetch()
// } // }
//#else //#else
curInstruction &= 0xFFFFFFFE; //please don't change this to 0x0FFFFFFE -- the NDS will happily run on 0xF******* addresses all day long curInstruction &= 0xFFFFFFFE; //please don't change this to 0x0FFFFFFE -- the NDS will happily run on 0xF******* addresses all day long
armcpu->instruction = _MMU_read16<PROCNUM, MMU_AT_CODE>(curInstruction); //please note that we must setup R[15] before reading the instruction since there is a protection
//which prevents PC > 0x3FFF from reading the bios region
armcpu->instruct_adr = curInstruction; armcpu->instruct_adr = curInstruction;
armcpu->next_instruction = curInstruction + 2; armcpu->next_instruction = curInstruction + 2;
armcpu->R[15] = curInstruction + 4; armcpu->R[15] = curInstruction + 4;
armcpu->instruction = _MMU_read16<PROCNUM, MMU_AT_CODE>(curInstruction);
//#endif //#endif
if(PROCNUM==0) if(PROCNUM==0)