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Bus: Handle unaligned accesses in safe memory routines

This commit is contained in:
Connor McLaughlin 2021-09-15 12:23:05 +10:00
parent 14865d0007
commit f7f121f036
1 changed files with 34 additions and 7 deletions
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41
src/core/bus.cpp
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@ -1961,17 +1961,35 @@ bool SafeReadMemoryByte(VirtualMemoryAddress addr, u8* value)
bool SafeReadMemoryHalfWord(VirtualMemoryAddress addr, u16* value)
{
u32 temp = 0;
if (!DoSafeMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::HalfWord>(addr, temp))
if ((addr & 1) == 0)
{
u32 temp = 0;
if (!DoSafeMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::HalfWord>(addr, temp))
return false;
*value = Truncate16(temp);
return true;
}
u8 low, high;
if (!SafeReadMemoryByte(addr, &low) || !SafeReadMemoryByte(addr + 1, &high))
return false;
*value = Truncate16(temp);
*value = (ZeroExtend16(high) << 8) | ZeroExtend16(low);
return true;
}
bool SafeReadMemoryWord(VirtualMemoryAddress addr, u32* value)
{
return DoSafeMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(addr, *value);
if ((addr & 3) == 0)
return DoSafeMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(addr, *value);
u16 low, high;
if (!SafeReadMemoryHalfWord(addr, &low) || !SafeReadMemoryHalfWord(addr + 2, &high))
return false;
*value = (ZeroExtend32(high) << 16) | ZeroExtend32(low);
return true;
}
bool SafeWriteMemoryByte(VirtualMemoryAddress addr, u8 value)
@ -1982,13 +2000,22 @@ bool SafeWriteMemoryByte(VirtualMemoryAddress addr, u8 value)
bool SafeWriteMemoryHalfWord(VirtualMemoryAddress addr, u16 value)
{
u32 temp = ZeroExtend32(value);
return DoSafeMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::HalfWord>(addr, temp);
if ((addr & 1) == 0)
{
u32 temp = ZeroExtend32(value);
return DoSafeMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::HalfWord>(addr, temp);
}
return SafeWriteMemoryByte(addr, Truncate8(value)) && SafeWriteMemoryByte(addr + 1, Truncate8(value >> 8));
}
bool SafeWriteMemoryWord(VirtualMemoryAddress addr, u32 value)
{
return DoSafeMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Word>(addr, value);
if ((addr & 3) == 0)
return DoSafeMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Word>(addr, value);
return SafeWriteMemoryHalfWord(addr, Truncate16(value >> 16)) &&
SafeWriteMemoryHalfWord(addr + 2, Truncate16(value >> 16));
}
void* GetDirectReadMemoryPointer(VirtualMemoryAddress address, MemoryAccessSize size, TickCount* read_ticks)