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-rw-r--r--src/core/memory.cpp202
1 files changed, 202 insertions, 0 deletions
diff --git a/src/core/memory.cpp b/src/core/memory.cpp
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+++ b/src/core/memory.cpp
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+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <array>
+
+#include "common/assert.h"
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "common/swap.h"
+
+#include "core/hle/config_mem.h"
+#include "core/hle/shared_page.h"
+#include "core/hw/hw.h"
+#include "core/mem_map.h"
+#include "core/memory.h"
+
+namespace Memory {
+
+const u32 PAGE_MASK = PAGE_SIZE - 1;
+const int PAGE_BITS = 12;
+
+enum class PageType {
+ /// Page is unmapped and should cause an access error.
+ Unmapped,
+ /// Page is mapped to regular memory. This is the only type you can get pointers to.
+ Memory,
+ /// Page is mapped to a I/O region. Writing and reading to this page is handled by functions.
+ Special,
+};
+
+/**
+ * A (reasonably) fast way of allowing switchable and remmapable process address spaces. It loosely
+ * mimics the way a real CPU page table works, but instead is optimized for minimal decoding and
+ * fetching requirements when acessing. In the usual case of an access to regular memory, it only
+ * requires an indexed fetch and a check for NULL.
+ */
+struct PageTable {
+ static const size_t NUM_ENTRIES = 1 << (32 - PAGE_BITS);
+
+ /**
+ * Array of memory pointers backing each page. An entry can only be non-null if the
+ * corresponding entry in the `attributes` array is of type `Memory`.
+ */
+ std::array<u8*, NUM_ENTRIES> pointers;
+
+ /**
+ * Array of fine grained page attributes. If it is set to any value other than `Memory`, then
+ * the corresponding entry in `pointer` MUST be set to null.
+ */
+ std::array<PageType, NUM_ENTRIES> attributes;
+};
+
+/// Singular page table used for the singleton process
+static PageTable main_page_table;
+/// Currently active page table
+static PageTable* current_page_table = &main_page_table;
+
+static void MapPages(u32 base, u32 size, u8* memory, PageType type) {
+ LOG_DEBUG(HW_Memory, "Mapping %p onto %08X-%08X", memory, base * PAGE_SIZE, (base + size) * PAGE_SIZE);
+
+ u32 end = base + size;
+
+ while (base != end) {
+ ASSERT_MSG(base < PageTable::NUM_ENTRIES, "out of range mapping at %08X", base);
+
+ if (current_page_table->attributes[base] != PageType::Unmapped) {
+ LOG_ERROR(HW_Memory, "overlapping memory ranges at %08X", base * PAGE_SIZE);
+ }
+ current_page_table->attributes[base] = type;
+ current_page_table->pointers[base] = memory;
+
+ base += 1;
+ memory += PAGE_SIZE;
+ }
+}
+
+void InitMemoryMap() {
+ main_page_table.pointers.fill(nullptr);
+ main_page_table.attributes.fill(PageType::Unmapped);
+}
+
+void MapMemoryRegion(VAddr base, u32 size, u8* target) {
+ ASSERT_MSG((size & PAGE_MASK) == 0, "non-page aligned size: %08X", size);
+ ASSERT_MSG((base & PAGE_MASK) == 0, "non-page aligned base: %08X", base);
+ MapPages(base / PAGE_SIZE, size / PAGE_SIZE, target, PageType::Memory);
+}
+
+void MapIoRegion(VAddr base, u32 size) {
+ ASSERT_MSG((size & PAGE_MASK) == 0, "non-page aligned size: %08X", size);
+ ASSERT_MSG((base & PAGE_MASK) == 0, "non-page aligned base: %08X", base);
+ MapPages(base / PAGE_SIZE, size / PAGE_SIZE, nullptr, PageType::Special);
+}
+
+template <typename T>
+T Read(const VAddr vaddr) {
+ const u8* page_pointer = current_page_table->pointers[vaddr >> PAGE_BITS];
+ if (page_pointer) {
+ return *reinterpret_cast<const T*>(page_pointer + (vaddr & PAGE_MASK));
+ }
+
+ PageType type = current_page_table->attributes[vaddr >> PAGE_BITS];
+ switch (type) {
+ case PageType::Unmapped:
+ LOG_ERROR(HW_Memory, "unmapped Read%lu @ 0x%08X", sizeof(T) * 8, vaddr);
+ return 0;
+ case PageType::Memory:
+ ASSERT_MSG(false, "Mapped memory page without a pointer @ %08X", vaddr);
+ case PageType::Special:
+ LOG_ERROR(HW_Memory, "I/O reads aren't implemented yet @ %08X", vaddr);
+ return 0;
+ default:
+ UNREACHABLE();
+ }
+}
+
+template <typename T>
+void Write(const VAddr vaddr, const T data) {
+ u8* page_pointer = current_page_table->pointers[vaddr >> PAGE_BITS];
+ if (page_pointer) {
+ *reinterpret_cast<T*>(page_pointer + (vaddr & PAGE_MASK)) = data;
+ return;
+ }
+
+ PageType type = current_page_table->attributes[vaddr >> PAGE_BITS];
+ switch (type) {
+ case PageType::Unmapped:
+ LOG_ERROR(HW_Memory, "unmapped Write%lu 0x%08X @ 0x%08X", sizeof(data) * 8, (u32) data, vaddr);
+ return;
+ case PageType::Memory:
+ ASSERT_MSG(false, "Mapped memory page without a pointer @ %08X", vaddr);
+ case PageType::Special:
+ LOG_ERROR(HW_Memory, "I/O writes aren't implemented yet @ %08X", vaddr);
+ return;
+ default:
+ UNREACHABLE();
+ }
+}
+
+u8* GetPointer(const VAddr vaddr) {
+ u8* page_pointer = current_page_table->pointers[vaddr >> PAGE_BITS];
+ if (page_pointer) {
+ return page_pointer + (vaddr & PAGE_MASK);
+ }
+
+ LOG_ERROR(HW_Memory, "unknown GetPointer @ 0x%08x", vaddr);
+ return nullptr;
+}
+
+u8* GetPhysicalPointer(PAddr address) {
+ return GetPointer(PhysicalToVirtualAddress(address));
+}
+
+u8 Read8(const VAddr addr) {
+ return Read<u8>(addr);
+}
+
+u16 Read16(const VAddr addr) {
+ return Read<u16_le>(addr);
+}
+
+u32 Read32(const VAddr addr) {
+ return Read<u32_le>(addr);
+}
+
+u64 Read64(const VAddr addr) {
+ return Read<u64_le>(addr);
+}
+
+void Write8(const VAddr addr, const u8 data) {
+ Write<u8>(addr, data);
+}
+
+void Write16(const VAddr addr, const u16 data) {
+ Write<u16_le>(addr, data);
+}
+
+void Write32(const VAddr addr, const u32 data) {
+ Write<u32_le>(addr, data);
+}
+
+void Write64(const VAddr addr, const u64 data) {
+ Write<u64_le>(addr, data);
+}
+
+void WriteBlock(const VAddr addr, const u8* data, const size_t size) {
+ u32 offset = 0;
+ while (offset < (size & ~3)) {
+ Write32(addr + offset, *(u32*)&data[offset]);
+ offset += 4;
+ }
+
+ if (size & 2) {
+ Write16(addr + offset, *(u16*)&data[offset]);
+ offset += 2;
+ }
+
+ if (size & 1)
+ Write8(addr + offset, data[offset]);
+}
+
+} // namespace