Start handling exheader flag0

include/loader/ncch.hpp

@@ -47,6 +47,9 @@ struct NCCH {
 	bool seedCrypto = false;
 	u8 secondaryKeySlot = 0;
 
+	// Contains info such as the ideal processor for threads, affinity mask, and how much memory should be reserved for the application
+	u8 flag0 = 0;
+
 	static constexpr u64 mediaUnit = 0x200;
 	u64 size = 0;  // Size of NCCH converted to bytes
 	u32 stackSize = 0;

include/memory.hpp

@@ -123,16 +123,21 @@ public:
 	static constexpr u32 pageMask = pageSize - 1;
 	static constexpr u32 totalPageCount = 1 << (32 - pageShift);
 	
-	static constexpr u32 FCRAM_SIZE = u32(128_MB);
-	static constexpr u32 FCRAM_APPLICATION_SIZE = u32(64_MB);
+	// TODO: All of these change on N3DS
+	static constexpr u32 FCRAM_SIZE = u32(128_MB);  // Total amount of FCRAM
 	static constexpr u32 FCRAM_PAGE_COUNT = FCRAM_SIZE / pageSize;
-	static constexpr u32 FCRAM_APPLICATION_PAGE_COUNT = FCRAM_APPLICATION_SIZE / pageSize;
+	static constexpr u32 FCRAM_MAX_APPLICATION_SIZE = u32(96_MB);  // Max amount available for applications
+	static constexpr u32 FCRAM_APPLICATION_MAX_PAGE_COUNT = FCRAM_MAX_APPLICATION_SIZE / pageSize;
 
 	static constexpr u32 DSP_RAM_SIZE = u32(512_KB);
 	static constexpr u32 DSP_CODE_MEMORY_OFFSET = u32(0_KB);
 	static constexpr u32 DSP_DATA_MEMORY_OFFSET = u32(256_KB);
 
 private:
+	// This will get adjusted based on the cartridge exheader via setFcramApplicationSize, 64MB is just a default
+	u32 fcramApplicationSize = u32(64_MB);
+	u32 fcramApplicationPageCount = u32(64_MB) / pageSize;  // Same here
+
 	std::bitset<FCRAM_PAGE_COUNT> usedFCRAMPages;
 	std::optional<u32> findPaddr(u32 size);
 	u64 timeSince3DSEpoch();
@@ -186,9 +191,23 @@ public:
 	u32 getLinearHeapVaddr();
 	u8* getFCRAM() { return fcram; }
 
+	// Set the amount of application FCRAM
+	void setApplicationRamSize(u32 size) {
+		fcramApplicationSize = size;
+		fcramApplicationPageCount = size / pageSize;
+
+		if (usedUserMemory > fcramApplicationSize) {
+			Helpers::panic("Set application FCRAM to a value less than the currently used application memory");
+		}
+
+		if (usedSystemMemory > totalSysFCRAM()) {
+			Helpers::panic("Set system FCRAM to a value less than the currently used system memory");
+		}
+	}
+
 	// Total amount of OS-only FCRAM available (Can vary depending on how much FCRAM the app requests via the cart exheader)
 	u32 totalSysFCRAM() {
-		return FCRAM_SIZE - FCRAM_APPLICATION_SIZE;
+		return FCRAM_SIZE - fcramApplicationSize;
 	}
 
 	// Amount of OS-only FCRAM currently available
@@ -198,8 +217,8 @@ public:
 
 	// Physical FCRAM index to the start of OS FCRAM
 	// We allocate the first part of physical FCRAM for the application, and the rest to the OS. So the index for the OS = application ram size
-	u32 sysFCRAMIndex() {
-		return FCRAM_APPLICATION_SIZE;
+	u32 sysFCRAMStartIndex() {
+		return fcramApplicationSize;
 	}
 
 	enum class BatteryLevel {

src/core/loader/elf.cpp

@@ -21,6 +21,9 @@ std::optional<u32> Memory::loadELF(std::ifstream& file) {
 		return std::nullopt;
 	}
 
+    // Use 64MB of application FCRAM for ELFs by default
+    setApplicationRamSize(64_MB);
+
     auto segNum = reader.segments.size();
     printf("Number of segments: %d\n", segNum);
     printf(" #  Perms       Vaddr           File Size       Mem Size\n");

src/core/loader/ncch.cpp

@@ -160,6 +160,10 @@ bool NCCH::loadFromHeader(Crypto::AESEngine &aesEngine, IOFile& file, const FSIn
 		text.extract(&exheader[0x10]);
 		rodata.extract(&exheader[0x20]);
 		data.extract(&exheader[0x30]);
+
+		// Access Control Info section of the exheader
+		const u8* aci = &exheader[0x200];
+		flag0 = aci[0xE];
 	}
 
 	printf("Stack size: %08X\nBSS size: %08X\n", stackSize, bssSize);

src/core/loader/ncsd.cpp

@@ -13,6 +13,31 @@ bool Memory::mapCXI(NCSD& ncsd, NCCH& cxi) {
 
 	static constexpr std::array<const char*, 7> regionNames = {"Japan", "North America", "Europe", "Australia", "China", "Korea", "Taiwan" };
 
+	// The application RAM sizes for Old 3DS titles, chosen based on flag0 of the exheader
+	static constexpr std::array<u32, 16> applicationRamSizes_O3DS = {
+		64_MB,  // Prod
+		64_MB,  // Unused
+		96_MB,  // Dev1
+		80_MB,  // Dev2
+		72_MB,  // Dev3
+		32_MB,  // Dev4
+		64_MB, 64_MB, 64_MB, 64_MB, 64_MB, 64_MB, 64_MB, 64_MB, 64_MB, 64_MB,
+	};
+
+	// Similar for New 3DS titles chosed based on flag2 from exheader. Index 0 isn't actually used, and denotes that this should use the Old3DS setting
+	[[maybe_unused]] static constexpr std::array<u32, 16> applicationRamSizes_New3DS = {
+		64_MB,   // Legacy mode
+		124_MB,  // Prod
+		178_MB,  // Dev1
+		124_MB,  // Dev2
+		124_MB, 124_MB, 124_MB, 124_MB, 124_MB, 124_MB, 124_MB, 124_MB, 124_MB, 124_MB, 124_MB, 124_MB,
+	};
+
+	// TODO: Handle N3DS FCRAM here
+	const u32 memorySize = applicationRamSizes_O3DS[Helpers::getBits<4, 4>(cxi.flag0)];
+	setApplicationRamSize(memorySize);
+	printf("Set application RAM size to %dMB\n", u32(memorySize / 1_MB));
+
 	// Set autodetected 3DS region to one of the values allowed by the CXI's SMDH
 	region = cxi.region.value();
 	printf("Console region autodetected to: %s\n", regionNames[static_cast<size_t>(region)]);

src/core/memory.cpp

@@ -289,12 +289,12 @@ std::optional<u32> Memory::allocateMemory(u32 vaddr, u32 paddr, u32 size, bool l
 	// Additionally assert we don't OoM and that we don't try to allocate physical FCRAM past what's available to userland
 	// If we're mapping there's no fear of OoM, because we're not really allocating memory, just binding vaddrs to specific paddrs
 	assert(isAligned(vaddr) && isAligned(paddr) && isAligned(size));
-	assert(size <= FCRAM_APPLICATION_SIZE || isMap);
-	assert(usedUserMemory + size <= FCRAM_APPLICATION_SIZE || isMap);
-	assert(paddr + size <= FCRAM_APPLICATION_SIZE || isMap);
+	assert(size <= fcramApplicationSize || isMap);
+	assert(usedUserMemory + size <= fcramApplicationSize || isMap);
+	assert(paddr + size <= fcramApplicationSize || isMap);
 
 	// Amount of available user FCRAM pages and FCRAM pages to allocate respectively
-	const u32 availablePageCount = (FCRAM_APPLICATION_SIZE - usedUserMemory) / pageSize;
+	const u32 availablePageCount = (fcramApplicationSize - usedUserMemory) / pageSize;
 	const u32 neededPageCount = size / pageSize;
 
 	assert(availablePageCount >= neededPageCount || isMap);
@@ -367,7 +367,7 @@ std::optional<u32> Memory::findPaddr(u32 size) {
 	// If this ends up >= than neededPages then the paddr is good (ie we can use the candidate page as a base address)
 	u32 counter = 0;
 
-	for (u32 i = 0; i < FCRAM_APPLICATION_PAGE_COUNT; i++) {
+	for (u32 i = 0; i < fcramApplicationPageCount; i++) {
 		if (usedFCRAMPages[i]) {  // Page is occupied already, go to new candidate
 			candidatePage = i + 1;
 			counter = 0;
@@ -392,19 +392,22 @@ u32 Memory::allocateSysMemory(u32 size) {
 	}
 
 	// We use a pretty dumb allocator for OS memory since this is not really accessible to the app and is only used internally
-	// It works by just allocating memory linearly, starting from index 0 of OS memory and going up
+	// It works by just allocating memory linearly, starting from the end of system memory and going back
+	// This happens in order to allow changing the size of application FCRAM when loading a ROM, and not risking messing up our data
 	// This should also be unreachable in practice and exists as a sanity check
 	if (size > remainingSysFCRAM()) {
 		Helpers::panic("Memory::allocateSysMemory: Overflowed OS FCRAM");
 	}
 
-	const u32 pageCount = size / pageSize;                      // Number of pages that will be used up
-	const u32 startIndex = sysFCRAMIndex() + usedSystemMemory;  // Starting FCRAM index
+	const u32 pageCount = size / pageSize;                                     // Number of pages that will be used up
+	const u32 startIndex = FCRAM_SIZE - usedSystemMemory - size;  // Starting FCRAM index
 	const u32 startingPage = startIndex / pageSize;
 
 	for (u32 i = 0; i < pageCount; i++) {
-		if (usedFCRAMPages[startingPage + i])  // Also a theoretically unreachable panic for safety
+		if (usedFCRAMPages[startingPage + i]) {  // Also a theoretically unreachable panic for safety
 			Helpers::panic("Memory::reserveMemory: Trying to reserve already reserved memory");
+		}
+
 		usedFCRAMPages[startingPage + i] = true;
 	}
 

src/emulator.cpp

@@ -444,6 +444,8 @@ bool Emulator::loadROM(const std::filesystem::path& path) {
 	}
 
 	kernel.initializeFS();
+	memory.setApplicationRamSize(64_MB); // Set the application RAM size to a default 64MB that loaded apps can override if needed
+
 	auto extension = path.extension();
 	bool success;  // Tracks if we loaded the ROM successfully