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core/memory: Fix undefined behavior and optimize Luma alias path (#2202)

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* core/memory: Fix undefined behavior and optimize Luma alias path

* chore: clean up Luma mapping comments

* style: fix clang-format formatting
This commit is contained in:
0x48kirenh 2026-06-17 09:13:56 +02:00 committed by GitHub
parent f015a208e5
commit 735c63174c
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1 changed files with 26 additions and 14 deletions
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40
src/core/memory.cpp
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@ -598,19 +598,25 @@ T MemorySystem::Read(const std::shared_ptr<PageTable>& page_table, const VAddr v
return value; return value;
} }
// Custom Luma3ds mapping // Custom Luma3ds mapping (bit 31 set) Bypasses page tables for FCRAM/MMIO
// Is there a more efficient way to do this? constexpr VAddr LUMA_ALIAS_BIT = 0x80000000u;
if (vaddr & (1 << 31)) {
PAddr paddr = (vaddr & ~(1 << 31)); if (vaddr & LUMA_ALIAS_BIT) [[unlikely]] {
if ((paddr & 0xF0000000) == Memory::FCRAM_PADDR) { // Check FCRAM region const PAddr paddr = vaddr & ~LUMA_ALIAS_BIT;
// FCRAM (0x2xxxxxxx)
if ((paddr & 0xF0000000) == Memory::FCRAM_PADDR) {
ReadType value; ReadType value;
std::memcpy(&value, GetFCRAMPointer(paddr - Memory::FCRAM_PADDR), read_size); std::memcpy(&value, GetFCRAMPointer(paddr - Memory::FCRAM_PADDR), read_size);
return value; return value;
} else if ((paddr & 0xF0000000) == 0x10000000 && }
paddr >= Memory::IO_AREA_PADDR) { // Check MMIO region
// MMIO (0x1xxxxxxx, >= IO_AREA_PADDR) - Strictly 32-bit
if ((paddr & 0xF0000000) == 0x10000000 && paddr >= Memory::IO_AREA_PADDR) [[unlikely]] {
return static_cast<ReadType>(impl->system.GPU().ReadReg( return static_cast<ReadType>(impl->system.GPU().ReadReg(
static_cast<VAddr>(paddr) - Memory::IO_AREA_PADDR + 0x1EC00000)); static_cast<VAddr>(paddr) - Memory::IO_AREA_PADDR + 0x1EC00000));
} }
// Fallthrough: Standard page table lookup
} }
PageType type = page_table->attributes[vaddr >> CITRA_PAGE_BITS]; PageType type = page_table->attributes[vaddr >> CITRA_PAGE_BITS];
@ -686,21 +692,27 @@ void MemorySystem::Write(const std::shared_ptr<PageTable>& page_table, const VAd
return; return;
} }
// Custom Luma3ds mapping // Custom Luma3ds mapping (bit 31 set) Bypasses page tables for FCRAM/MMIO
// Is there a more efficient way to do this? constexpr VAddr LUMA_ALIAS_BIT = 0x80000000u;
if (vaddr & (1 << 31)) {
PAddr paddr = (vaddr & ~(1 << 31)); if (vaddr & LUMA_ALIAS_BIT) [[unlikely]] {
if ((paddr & 0xF0000000) == Memory::FCRAM_PADDR) { // Check FCRAM region const PAddr paddr = vaddr & ~LUMA_ALIAS_BIT;
// FCRAM (0x2xxxxxxx)
if ((paddr & 0xF0000000) == Memory::FCRAM_PADDR) {
std::memcpy(GetFCRAMPointer(paddr - Memory::FCRAM_PADDR), &data, sizeof(T)); std::memcpy(GetFCRAMPointer(paddr - Memory::FCRAM_PADDR), &data, sizeof(T));
return; return;
} else if ((paddr & 0xF0000000) == 0x10000000 && }
paddr >= Memory::IO_AREA_PADDR) { // Check MMIO region
// MMIO (0x1xxxxxxx, >= IO_AREA_PADDR) - Strictly 32-bit
if ((paddr & 0xF0000000) == 0x10000000 && paddr >= Memory::IO_AREA_PADDR) [[unlikely]] {
ASSERT(sizeof(data) == sizeof(u32)); ASSERT(sizeof(data) == sizeof(u32));
impl->system.GPU().WriteReg(static_cast<VAddr>(paddr) - Memory::IO_AREA_PADDR + impl->system.GPU().WriteReg(static_cast<VAddr>(paddr) - Memory::IO_AREA_PADDR +
0x1EC00000, 0x1EC00000,
static_cast<u32>(data)); static_cast<u32>(data));
return; return;
} }
// Fallthrough: Standard page table lookup
} }
PageType type = page_table->attributes[vaddr >> CITRA_PAGE_BITS]; PageType type = page_table->attributes[vaddr >> CITRA_PAGE_BITS];