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Bus: Further tweaks to access timing

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Matches closely to my console now.

Fixes Otona No Asobi again.
This commit is contained in:
Connor McLaughlin
2020-06-01 21:39:31 +10:00
parent 7d66569d69
commit e5fc47a008
2 changed files with 63 additions and 23 deletions
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66
src/core/bus.cpp
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@ -25,7 +25,7 @@ Log_SetChannel(Bus);
#define FIXUP_HALFWORD_WRITE_VALUE(offset, value) ((value) << (((offset)&u32(1)) * 8u))
// Offset and value remapping for (w32) registers from nocash docs.
void FixupUnalignedWordAccessW32(u32& offset, u32& value)
ALWAYS_INLINE static void FixupUnalignedWordAccessW32(u32& offset, u32& value)
{
const u32 byte_offset = offset & u32(3);
offset &= ~u32(3);
@ -426,39 +426,79 @@ void Bus::DoWriteSIO(MemoryAccessSize size, u32 offset, u32 value)
u32 Bus::DoReadCDROM(MemoryAccessSize size, u32 offset)
{
// TODO: Splitting of half/word reads.
Assert(size == MemoryAccessSize::Byte);
return ZeroExtend32(m_cdrom->ReadRegister(offset));
switch (size)
{
case MemoryAccessSize::Word:
{
const u32 b0 = ZeroExtend32(m_cdrom->ReadRegister(offset));
const u32 b1 = ZeroExtend32(m_cdrom->ReadRegister(offset + 1u));
const u32 b2 = ZeroExtend32(m_cdrom->ReadRegister(offset + 2u));
const u32 b3 = ZeroExtend32(m_cdrom->ReadRegister(offset + 3u));
return b0 | (b1 << 8) | (b2 << 16) | (b3 << 24);
}
case MemoryAccessSize::HalfWord:
{
const u32 lsb = ZeroExtend32(m_cdrom->ReadRegister(offset));
const u32 msb = ZeroExtend32(m_cdrom->ReadRegister(offset + 1u));
return lsb | (msb << 8);
}
case MemoryAccessSize::Byte:
default:
return ZeroExtend32(m_cdrom->ReadRegister(offset));
}
}
void Bus::DoWriteCDROM(MemoryAccessSize size, u32 offset, u32 value)
{
// TODO: Splitting of half/word reads.
Assert(size == MemoryAccessSize::Byte);
m_cdrom->WriteRegister(offset, Truncate8(value));
switch (size)
{
case MemoryAccessSize::Word:
{
m_cdrom->WriteRegister(offset, Truncate8(value & 0xFFu));
m_cdrom->WriteRegister(offset + 1u, Truncate8((value >> 8) & 0xFFu));
m_cdrom->WriteRegister(offset + 2u, Truncate8((value >> 16) & 0xFFu));
m_cdrom->WriteRegister(offset + 3u, Truncate8((value >> 24) & 0xFFu));
}
break;
case MemoryAccessSize::HalfWord:
{
m_cdrom->WriteRegister(offset, Truncate8(value & 0xFFu));
m_cdrom->WriteRegister(offset + 1u, Truncate8((value >> 8) & 0xFFu));
}
break;
case MemoryAccessSize::Byte:
default:
return m_cdrom->WriteRegister(offset, Truncate8(value));
}
}
u32 Bus::DoReadGPU(MemoryAccessSize size, u32 offset)
{
Assert(size == MemoryAccessSize::Word);
return m_gpu->ReadRegister(offset);
u32 value = m_gpu->ReadRegister(offset);
FixupUnalignedWordAccessW32(offset, value);
return value;
}
void Bus::DoWriteGPU(MemoryAccessSize size, u32 offset, u32 value)
{
Assert(size == MemoryAccessSize::Word);
FixupUnalignedWordAccessW32(offset, value);
m_gpu->WriteRegister(offset, value);
}
u32 Bus::DoReadMDEC(MemoryAccessSize size, u32 offset)
{
Assert(size == MemoryAccessSize::Word);
return m_mdec->ReadRegister(offset);
u32 value = m_mdec->ReadRegister(offset);
FixupUnalignedWordAccessW32(offset, value);
return value;
}
void Bus::DoWriteMDEC(MemoryAccessSize size, u32 offset, u32 value)
{
Assert(size == MemoryAccessSize::Word);
FixupUnalignedWordAccessW32(offset, value);
m_mdec->WriteRegister(offset, value);
}