diff --git a/include/functions.h b/include/functions.h
index cfa7f4fad6..3c20bca11c 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -194,16 +194,7 @@ s32 func_80086D40(f64 param_1);
 f64 func_80086D6C(f64 param_1);
 s32 func_80086D8C(f32 param_1);
 s32 func_80086DAC(f64 param_1);
-void* SystemArena_Malloc(size_t size);
-void* SystemArena_MallocR(size_t size);
-void* SystemArena_Realloc(void* oldPtr, size_t newSize);
-void SystemArena_Free(void* ptr);
-void* SystemArena_Calloc(u32 elements, size_t size);
-void SystemArena_AnalyzeArena(size_t* maxFreeBlock, size_t* bytesFree, size_t* bytesAllocated);
-u32 SystemArena_CheckArena(void);
-void SystemArena_InitArena(void* start, size_t size);
-void SystemArena_Cleanup(void);
-u8 SystemArena_IsInitialized(void);
+
 s32 Rand_Next(void);
 void Rand_Seed(u32 seed);
 f32 Rand_ZeroOne(void);
@@ -212,20 +203,7 @@ void Rand_Seed_Variable(u32* rndNum, u32 seed);
 u32 Rand_Next_Variable(u32* param_1);
 f32 Rand_ZeroOne_Variable(u32* param_1);
 f32 Rand_Centered_Variable(u32* param_1);
-void ArenaImpl_LockInit(Arena* heap);
-void ArenaImpl_Lock(Arena* heap);
-void ArenaImpl_Unlock(Arena* heap);
-ArenaNode* ArenaImpl_GetLastBlock(Arena* param_1);
-void __osMallocInit(Arena* heap, void* heapBase, size_t heapSize);
-void __osMallocAddBlock(Arena* heap, void* start, s32 size);
-void __osMallocCleanup(Arena* heap);
-u8 __osMallocIsInitalized(Arena* heap);
-void* __osMalloc(Arena* heap, size_t size);
-void* __osMallocR(Arena* heap, size_t size);
-void __osFree(Arena* heap, void* ptr);
-void* __osRealloc(Arena* heap, void* oldPtr, size_t newSize);
-void __osAnalyzeArena(Arena* heap, size_t* maxFreeBlock, size_t* bytesFree, size_t* bytesAllocated);
-u32 __osCheckArena(Arena* heap);
+
 void* proutSprintf(void* s, const char* buf, size_t n);
 s32 vsprintf(char* dst, char* fmt, va_list args);
 s32 sprintf(char* s, char* fmt, ...);
@@ -1769,7 +1747,7 @@ void* ZeldaArena_Realloc(void* oldPtr, size_t newSize);
 void ZeldaArena_Free(void* param_1);
 void* ZeldaArena_Calloc(u32 num, size_t size);
 void ZeldaArena_GetSizes(size_t* maxFreeBlock, size_t* bytesFree, size_t* bytesAllocated);
-void ZeldaArena_Check();
+s32 ZeldaArena_Check();
 void ZeldaArena_Init(void* start, size_t size);
 void ZeldaArena_Cleanup();
 u8 ZeldaArena_IsInitialized();
diff --git a/include/macros.h b/include/macros.h
index 7e6104317a..21593c13b6 100644
--- a/include/macros.h
+++ b/include/macros.h
@@ -2,7 +2,7 @@
 #define _MACROS_H_
 
 #include "libc/stdint.h"
-#include "convert.h"
+#include "ultra64/convert.h"
 #include "z64.h"
 
 #define SCREEN_WIDTH  320
diff --git a/include/os_malloc.h b/include/os_malloc.h
new file mode 100644
index 0000000000..6b1cceab5a
--- /dev/null
+++ b/include/os_malloc.h
@@ -0,0 +1,35 @@
+#ifndef OS_MALLOC
+#define OS_MALLOC
+
+#include "PR/ultratypes.h"
+#include "ultra64/message.h"
+#include "libc/stddef.h"
+
+typedef struct ArenaNode {
+    /* 0x0 */ s16 magic; // Should always be 0x7373
+    /* 0x2 */ s16 isFree;
+    /* 0x4 */ size_t size;
+    /* 0x8 */ struct ArenaNode* next;
+    /* 0xC */ struct ArenaNode* prev;
+} ArenaNode; // size = 0x10
+
+typedef struct {
+    /* 0x00 */ ArenaNode* head;
+    /* 0x04 */ void* start;
+    /* 0x08 */ OSMesgQueue lock;
+    /* 0x20 */ u8 unk20;
+    /* 0x21 */ u8 isInit;
+    /* 0x22 */ u8 flag;
+} Arena; // size = 0x24
+
+void __osMallocInit(Arena* arena, void* heap, size_t size);
+void __osMallocCleanup(Arena* arena);
+u8 __osMallocIsInitalized(Arena* arena);
+void* __osMalloc(Arena* arena, size_t size);
+void* __osMallocR(Arena* arena, size_t size);
+void __osFree(Arena* arena, void* ptr);
+void* __osRealloc(Arena* arena, void* ptr, size_t newSize);
+void __osGetSizes(Arena* arena, size_t* maxFreeBlock, size_t* bytesFree, size_t* bytesAllocated);
+s32 __osCheckArena(Arena* arena);
+
+#endif
diff --git a/include/system_malloc.h b/include/system_malloc.h
new file mode 100644
index 0000000000..e92eaf89fd
--- /dev/null
+++ b/include/system_malloc.h
@@ -0,0 +1,20 @@
+#ifndef SYSTEM_MALLOC
+#define SYSTEM_MALLOC
+
+#include "PR/ultratypes.h"
+#include "os_malloc.h"
+
+void* SystemArena_Malloc(size_t size);
+void* SystemArena_MallocR(size_t size);
+void* SystemArena_Realloc(void* oldPtr, size_t newSize);
+void SystemArena_Free(void* ptr);
+void* SystemArena_Calloc(u32 elements, size_t size);
+void SystemArena_GetSizes(size_t* maxFreeBlock, size_t* bytesFree, size_t* bytesAllocated);
+u32 SystemArena_CheckArena(void);
+void SystemArena_InitArena(void* start, size_t size);
+void SystemArena_Cleanup(void);
+u8 SystemArena_IsInitialized(void);
+
+extern Arena gSystemArena;
+
+#endif
diff --git a/include/convert.h b/include/ultra64/convert.h
similarity index 94%
rename from include/convert.h
rename to include/ultra64/convert.h
index c453e18e3a..59d8b801c3 100644
--- a/include/convert.h
+++ b/include/ultra64/convert.h
@@ -1,5 +1,5 @@
-#ifndef _ULTRA64_CONVERT_H_
-#define _ULTRA64_CONVERT_H_
+#ifndef ULTRA64_CONVERT_H
+#define ULTRA64_CONVERT_H
 
 #include "libc/stdint.h"
 
diff --git a/include/variables.h b/include/variables.h
index 6d1fc3ef96..cabe5d09e4 100644
--- a/include/variables.h
+++ b/include/variables.h
@@ -322,7 +322,6 @@ extern StackEntry sFaultThreadInfo;
 extern FaultThreadStruct gFaultStruct;
 extern FaultDrawer sFaultDrawerStruct;
 // extern UNK_TYPE4 D_8009CD10;
-// extern Arena gSystemArena;
 extern u32 sRandFloat;
 // extern UNK_TYPE4 sArenaLockMsg;
 extern OSTask tmp_task;
@@ -3271,7 +3270,6 @@ extern s16 D_801F4E7A;
 // extern UNK_TYPE1 D_801F4F68;
 // extern UNK_TYPE1 D_801F4F6A;
 extern LightsBuffer sLightsBuffer;
-extern Arena sZeldaArena;
 // extern UNK_TYPE1 D_801F5130;
 // extern UNK_TYPE1 D_801F5270;
 // extern UNK_TYPE1 D_801F528E;
diff --git a/include/z64.h b/include/z64.h
index 31eec335b7..1aba77e7af 100644
--- a/include/z64.h
+++ b/include/z64.h
@@ -884,23 +884,6 @@ typedef struct {
     /* 0x120D8 */ UNK_TYPE1 pad120D8[0x8];
 } MessageContext; // size = 0x120E0
 
-typedef struct ArenaNode {
-    /* 0x0 */ s16 magic; // Should always be 0x7373
-    /* 0x2 */ s16 isFree;
-    /* 0x4 */ size_t size;
-    /* 0x8 */ struct ArenaNode* next;
-    /* 0xC */ struct ArenaNode* prev;
-} ArenaNode; // size = 0x10
-
-typedef struct {
-    /* 0x00 */ ArenaNode* head;
-    /* 0x04 */ void* start;
-    /* 0x08 */ OSMesgQueue lock;
-    /* 0x20 */ u8 unk20;
-    /* 0x21 */ u8 isInit;
-    /* 0x22 */ u8 flag;
-} Arena; // size = 0x24
-
 typedef struct FaultAddrConvClient {
     /* 0x0 */ struct FaultAddrConvClient* next;
     /* 0x4 */ void* (*callback)(void*, void*);
diff --git a/spec b/spec
index aa2eacaea1..10b3e560e5 100644
--- a/spec
+++ b/spec
@@ -46,7 +46,6 @@ beginseg
     include "build/src/boot_O2/system_malloc.o"
     include "build/src/boot_O2/rand.o"
     include "build/src/boot_O2/__osMalloc.o"
-    include "build/data/boot/__osMalloc.bss.o"
     include "build/src/libultra/rmon/sprintf.o"
     include "build/src/boot_O2/printutils.o"
     include "build/src/boot_O2/sleep.o"
@@ -491,7 +490,6 @@ beginseg
     include "build/src/code/z_lights.o"
     include "build/data/code/z_lights.bss.o"
     include "build/src/code/z_malloc.o"
-    include "build/data/code/z_malloc.bss.o"
     include "build/src/code/z_map_disp.o"
     include "build/data/code/z_map_disp.data.o"
     include "build/data/code/z_map_disp.bss.o"
diff --git a/src/boot_O2/__osMalloc.c b/src/boot_O2/__osMalloc.c
index c74c34866b..24fa6d39ec 100644
--- a/src/boot_O2/__osMalloc.c
+++ b/src/boot_O2/__osMalloc.c
@@ -1,4 +1,8 @@
-#include "global.h"
+#include "os_malloc.h"
+#include "libc/stdbool.h"
+#include "libc/stdint.h"
+#include "macros.h"
+#include "functions.h"
 
 #define FILL_ALLOCBLOCK (1 << 0)
 #define FILL_FREEBLOCK (1 << 1)
@@ -13,9 +17,9 @@
 #define BLOCK_FREE_MAGIC (0xEF)
 #define BLOCK_FREE_MAGIC_32 (0xEFEFEFEF)
 
-extern OSMesg sArenaLockMsg[1];
+OSMesg sArenaLockMsg[1];
 
-#pragma GLOBAL_ASM("asm/non_matchings/boot/__osMalloc/D_80099110.s")
+void __osMallocAddHeap(Arena* arena, void* heap, size_t size);
 
 void ArenaImpl_LockInit(Arena* arena) {
     osCreateMesgQueue(&arena->lock, sArenaLockMsg, ARRAY_COUNT(sArenaLockMsg));
@@ -45,111 +49,184 @@ ArenaNode* ArenaImpl_GetLastBlock(Arena* arena) {
     return last;
 }
 
-void __osMallocInit(Arena* arena, void* start, size_t size) {
-    bzero(arena, sizeof(*arena));
+/**
+ * Initializes \p arena to manage the memory region \p heap.
+ *
+ * @param arena  The Arena to initialize.
+ * @param heap   The memory region to use as heap space.
+ * @param size   The size of the heap.
+ */
+void __osMallocInit(Arena* arena, void* heap, size_t size) {
+    bzero(arena, sizeof(Arena));
+
     ArenaImpl_LockInit(arena);
-    __osMallocAddBlock(arena, start, size);
-    arena->isInit = 1;
+
+    __osMallocAddHeap(arena, heap, size);
+    arena->isInit = true;
 }
 
-void __osMallocAddBlock(Arena* arena, void* start, s32 size) {
-    s32 diff;
-    s32 size2;
+// Original name: __osMallocAddBlock
+void __osMallocAddHeap(Arena* arena, void* heap, size_t size) {
+    ptrdiff_t diff;
+    s32 alignedSize;
     ArenaNode* firstNode;
     ArenaNode* lastNode;
 
-    if (start != NULL) {
-        firstNode = (ArenaNode*)ALIGN16((u32)start);
-        diff = (s32)firstNode - (s32)start;
-        size2 = (size - diff) & ~0xF;
+    if (heap == NULL) {
+        return;
+    }
 
-        if (size2 > (s32)sizeof(ArenaNode)) {
-            firstNode->next = NULL;
-            firstNode->prev = NULL;
-            firstNode->size = size2 - sizeof(ArenaNode);
-            firstNode->isFree = 1;
-            firstNode->magic = NODE_MAGIC;
-            ArenaImpl_Lock(arena);
-            lastNode = ArenaImpl_GetLastBlock(arena);
-            if (lastNode == NULL) {
-                arena->head = firstNode;
-                arena->start = start;
-            } else {
-                firstNode->prev = lastNode;
-                lastNode->next = firstNode;
-            }
-            ArenaImpl_Unlock(arena);
+    firstNode = (ArenaNode*)ALIGN16((uintptr_t)heap);
+    diff = (uintptr_t)firstNode - (uintptr_t)heap;
+    alignedSize = ((s32)size - diff) & ~0xF;
+
+    // If the size of the heap is smaller than sizeof(ArenaNode), then the initialization will silently fail
+    if (alignedSize > (s32)sizeof(ArenaNode)) {
+        firstNode->next = NULL;
+        firstNode->prev = NULL;
+        firstNode->size = alignedSize - sizeof(ArenaNode);
+        firstNode->isFree = true;
+        firstNode->magic = NODE_MAGIC;
+
+        ArenaImpl_Lock(arena);
+
+        lastNode = ArenaImpl_GetLastBlock(arena);
+
+        // Checks if there's already a block
+        if (lastNode == NULL) {
+            arena->head = firstNode;
+            arena->start = heap;
+        } else {
+            // Chain the existing block with the new one
+            firstNode->prev = lastNode;
+            lastNode->next = firstNode;
         }
+
+        ArenaImpl_Unlock(arena);
     }
 }
 
+/**
+ * Clears the whole \p arena, invalidating every allocated pointer to it.
+ *
+ * @param arena  The Arena to clear.
+ */
 void __osMallocCleanup(Arena* arena) {
-    bzero(arena, sizeof(*arena));
+    bzero(arena, sizeof(Arena));
 }
 
+/**
+ * Returns whether or not the \p arena has been initialized.
+ *
+ * @param arena  The Arena to check.
+ * @return u8    `true` if the \p arena has been initialized. `false` otherwise.
+ */
 u8 __osMallocIsInitalized(Arena* arena) {
     return arena->isInit;
 }
 
+/**
+ * Allocates at least \p size bytes of memory using the given \p arena.
+ * The block of memory will be allocated at the start of the first sufficiently large free block.
+ *
+ *  - If there's not enough space in the given \p arena, this function will fail, returning `NULL`.
+ *  - If \p size is zero, then an empty region of memory is returned.
+ *
+ * To avoid memory leaks, the returned pointer should be eventually deallocated using either `__osFree` or
+ * `__osRealloc`.
+ *
+ * @param[in, out] arena  The specific Arena to be used for the allocation.
+ * @param[in] size        The size in bytes that will be allocated.
+ * @return void*          On success, the allocated area of the \p arena memory. Otherwise, `NULL`.
+ */
 void* __osMalloc(Arena* arena, size_t size) {
     ArenaNode* iter;
     ArenaNode* newNode;
-    void* alloc;
-    u32 blockSize;
-    alloc = NULL;
+    void* alloc = NULL;
 
     size = ALIGN16(size);
+
     ArenaImpl_Lock(arena);
+
+    // Start iterating from the head of the arena.
     iter = arena->head;
 
+    // Iterate over the arena looking for a big enough space of memory.
     while (iter != NULL) {
         if (iter->isFree && iter->size >= size) {
-            ArenaNode* next;
-            blockSize = ALIGN16(size) + sizeof(ArenaNode);
+            size_t blockSize = ALIGN16(size) + sizeof(ArenaNode);
+
+            // If the block is larger than the requested size, then split it and just use the required size of the
+            // current block.
             if (blockSize < iter->size) {
-                newNode = (ArenaNode*)((u32)iter + blockSize);
+                ArenaNode* next;
+
+                newNode = (ArenaNode*)((uintptr_t)iter + blockSize);
                 newNode->next = iter->next;
                 newNode->prev = iter;
                 newNode->size = iter->size - blockSize;
-                newNode->isFree = 1;
+                newNode->isFree = true;
                 newNode->magic = NODE_MAGIC;
 
                 iter->next = newNode;
                 iter->size = size;
+
                 next = newNode->next;
-                if (next) {
+                if (next != NULL) {
                     next->prev = newNode;
                 }
             }
 
-            iter->isFree = 0;
-            alloc = (void*)((u32)iter + sizeof(ArenaNode));
+            iter->isFree = false;
+            alloc = (void*)((uintptr_t)iter + sizeof(ArenaNode));
             break;
         }
 
         iter = iter->next;
     }
+
     ArenaImpl_Unlock(arena);
 
     return alloc;
 }
 
+/**
+ * Allocates at least \p size bytes of memory using the given \p arena.
+ * Unlike __osMalloc, the block of memory will be allocated from the end of the \p arena.
+ *
+ * - If there's not enough space in the given \p arena, this function will fail, returning `NULL`.
+ * - If \p size is zero, then an empty region of memory is returned.
+ *
+ * To avoid memory leaks, the returned pointer should be eventually deallocated using `__osFree` or `__osRealloc`.
+ *
+ * @param[in, out] arena  The specific Arena to be used for the allocation.
+ * @param[in] size        The size in bytes that will be allocated.
+ * @return void*          On success, the allocated area of the \p arena memory. Otherwise, `NULL`.
+ */
 void* __osMallocR(Arena* arena, size_t size) {
     ArenaNode* iter;
     ArenaNode* newNode;
-    u32 blockSize;
+    size_t blockSize;
     void* alloc = NULL;
 
     size = ALIGN16(size);
+
     ArenaImpl_Lock(arena);
+
+    // Start iterating from the last block of the arena.
     iter = ArenaImpl_GetLastBlock(arena);
 
+    // Iterate in reverse the arena looking for a big enough space of memory.
     while (iter != NULL) {
         if (iter->isFree && iter->size >= size) {
-            ArenaNode* next;
             blockSize = ALIGN16(size) + sizeof(ArenaNode);
+
+            // If the block is larger than the requested size, then split it and just use the required size of the
+            // current block.
             if (blockSize < iter->size) {
-                newNode = (ArenaNode*)((u32)iter + (iter->size - size));
+                ArenaNode* next;
+
+                newNode = (ArenaNode*)((uintptr_t)iter + (iter->size - size));
                 newNode->next = iter->next;
                 newNode->prev = iter;
                 newNode->size = size;
@@ -157,69 +234,171 @@ void* __osMallocR(Arena* arena, size_t size) {
 
                 iter->next = newNode;
                 iter->size -= blockSize;
+
                 next = newNode->next;
-                if (next) {
+                if (next != NULL) {
                     next->prev = newNode;
                 }
                 iter = newNode;
             }
 
-            iter->isFree = 0;
-            alloc = (void*)((u32)iter + sizeof(ArenaNode));
+            iter->isFree = false;
+            alloc = (void*)((uintptr_t)iter + sizeof(ArenaNode));
             break;
         }
         iter = iter->prev;
     }
+
     ArenaImpl_Unlock(arena);
 
     return alloc;
 }
 
+/**
+ * Deallocates the pointer \p ptr previously allocated by `__osMalloc`, `__osMallocR` or `__osRealloc`.
+ * If \p ptr is `NULL` or it has been already been freed, then this function does nothing.
+ *
+ * - The behaviour is undefined if \p ptr is not a memory region returned by one of the cited allocating
+ * functions.
+ * - The behaviour is undefined if \p ptr doesn't correspond to the given \p arena.
+ * - Any access to the freed pointer is undefined behaviour.
+ *
+ * @param[in, out] arena  The specific Arena to be used for the allocation.
+ * @param[in, out] ptr    The allocated memory block to deallocate.
+ */
 void __osFree(Arena* arena, void* ptr) {
     ArenaNode* node;
     ArenaNode* next;
     ArenaNode* prev;
-    ArenaNode* newNext;
 
     ArenaImpl_Lock(arena);
+
     node = (ArenaNode*)((uintptr_t)ptr - sizeof(ArenaNode));
 
-    if (ptr == NULL || (node->magic != NODE_MAGIC) || node->isFree) {
-        goto end;
-    }
+    if (ptr != NULL && node->magic == NODE_MAGIC && !node->isFree) {
+        next = node->next;
+        prev = node->prev;
+        node->isFree = true;
 
-    next = node->next;
-    prev = node->prev;
-    node->isFree = true;
+        // Checks if the next node is contiguous to the current node and if it isn't currently allocated. Then merge the
+        // two nodes into one.
+        if ((uintptr_t)next == (uintptr_t)node + sizeof(ArenaNode) + node->size && next->isFree) {
+            ArenaNode* newNext = next->next;
 
-    newNext = next;
-    if ((uintptr_t)next == (uintptr_t)node + sizeof(ArenaNode) + node->size && next->isFree) {
-        newNext = next->next;
-        if (newNext != NULL) {
-            newNext->prev = node;
+            if (newNext != NULL) {
+                newNext->prev = node;
+            }
+
+            node->size += next->size + sizeof(ArenaNode);
+
+            node->next = newNext;
+            next = newNext;
         }
 
-        node->size += next->size + sizeof(ArenaNode);
+        // Checks if the previous node is contiguous to the current node and if it isn't currently allocated. Then merge
+        // the two nodes into one.
+        if (prev != NULL && prev->isFree && (uintptr_t)node == (uintptr_t)prev + sizeof(ArenaNode) + prev->size) {
+            if (next != NULL) {
+                next->prev = prev;
+            }
 
-        node->next = newNext;
-        next = newNext;
-    }
-
-    if (prev != NULL && prev->isFree && (uintptr_t)node == (uintptr_t)prev + sizeof(ArenaNode) + prev->size) {
-        if (next) {
-            next->prev = prev;
+            prev->next = next;
+            prev->size += node->size + sizeof(ArenaNode);
         }
-        prev->next = next;
-        prev->size += node->size + sizeof(ArenaNode);
     }
 
-end:
     ArenaImpl_Unlock(arena);
 }
 
-#pragma GLOBAL_ASM("asm/non_matchings/boot/__osMalloc/__osRealloc.s")
+/**
+ * Reallocates the pointer \p ptr.
+ * \p ptr must be either a pointer previously allocated by `__osMalloc`, `__osMallocR` or `__osRealloc` and
+ * not freed yet, or a `NULL` pointer.
+ *
+ * - If \p ptr is `NULL` a new pointer is allocated. See `__osMalloc` for more details.
+ * - If \p newSize is 0, then the given pointer is freed and `NULL` is returned. See `__osFree` for more details.
+ * - If \p newSize is bigger than the currently allocated allocated pointer, then the area of memory is expanded to a
+ * size big enough to fit the requested size.
+ *
+ * - The behaviour is undefined if \p ptr is not a memory region returned by one of the cited allocating
+ * functions.
+ * - The behaviour is undefined if \p ptr doesn't correspond to the given \p arena.
+ * - If the pointer is freed, then any access to the original freed pointer is undefined behaviour.
+ *
+ * @param[in, out] arena  The specific Arena to be used for the allocation.
+ * @param[in, out] ptr    The allocated memory block to deallocate.
+ * @param[in] newSize     The new requested size.
+ * @return void*          On success, the pointer to the reallocated area of memory. On failure, `NULL` is returned,
+ * and the original parameter \p ptr remains valid.
+ */
+void* __osRealloc(Arena* arena, void* ptr, size_t newSize) {
+    ArenaImpl_Lock(arena);
 
-void __osAnalyzeArena(Arena* arena, size_t* outMaxFree, size_t* outFree, size_t* outAlloc) {
+    (void)"__osRealloc(%08x, %d)\n";
+
+    if (ptr == NULL) {
+        // if the `ptr` is NULL, then allocate a new pointer with the specified size
+        // if newSize is 0, then __osMalloc would return a NULL pointer
+        ptr = __osMalloc(arena, newSize);
+    } else if (newSize == 0) {
+        // if the requested size is zero, then free the pointer
+        __osFree(arena, ptr);
+        ptr = NULL;
+    } else {
+        size_t diff;
+        void* newPtr;
+        // Gets the start of the ArenaNode pointer embedded
+        ArenaNode* node = (void*)((uintptr_t)ptr - sizeof(ArenaNode));
+
+        newSize = ALIGN16(newSize);
+
+        // Only reallocate the memory if the new size isn't smaller than the actual node size
+        if ((newSize != node->size) && (node->size < newSize)) {
+            ArenaNode* next = node->next;
+
+            diff = newSize - node->size;
+            // Checks if the next node is contiguous to the current allocated node and it has enough space to fit the
+            // new requested size
+            if (((uintptr_t)next == (uintptr_t)node + node->size + sizeof(ArenaNode)) && (next->isFree) &&
+                (next->size >= diff)) {
+                ArenaNode* next2 = next->next;
+
+                next->size = (next->size - diff);
+                if (next2 != NULL) {
+                    // Update the previous element of the linked list
+                    next2->prev = (void*)((uintptr_t)next + diff);
+                }
+
+                next2 = (void*)((uintptr_t)next + diff);
+                node->next = next2;
+                node->size = newSize;
+                __osMemcpy(next2, next, sizeof(ArenaNode));
+            } else {
+                // Create a new pointer and manually copy the data from the old pointer to the new one
+                newPtr = __osMalloc(arena, newSize);
+                if (newPtr != NULL) {
+                    bcopy(newPtr, ptr, node->size);
+                    __osFree(arena, ptr);
+                }
+                ptr = newPtr;
+            }
+        }
+    }
+
+    ArenaImpl_Unlock(arena);
+
+    return ptr;
+}
+
+/**
+ * Gets the size of the largest free block, the total free space and the total allocated space.
+ *
+ * @param[in, out] arena   The Arena which will be used to get the values from.
+ * @param[out] outMaxFree  The size of the largest free block.
+ * @param[out] outFree     The total free space.
+ * @param[out] outAlloc    The total allocated space.
+ */
+void __osGetSizes(Arena* arena, size_t* outMaxFree, size_t* outFree, size_t* outAlloc) {
     ArenaNode* iter;
 
     ArenaImpl_Lock(arena);
@@ -245,4 +424,35 @@ void __osAnalyzeArena(Arena* arena, size_t* outMaxFree, size_t* outFree, size_t*
     ArenaImpl_Unlock(arena);
 }
 
-#pragma GLOBAL_ASM("asm/non_matchings/boot/__osMalloc/__osCheckArena.s")
+/**
+ * Checks the validity of every node of the \p arena.
+ *
+ * @param arena  The Arena to check.
+ * @return s32   0 if every pointer is valid. 1 otherwise.
+ */
+s32 __osCheckArena(Arena* arena) {
+    ArenaNode* iter;
+    s32 err = 0;
+
+    ArenaImpl_Lock(arena);
+
+    // "Checking the contents of the arena..."
+    (void)"アリーナの内容をチェックしています．．． (%08x)\n";
+
+    for (iter = arena->head; iter != NULL; iter = iter->next) {
+        if (iter->magic != NODE_MAGIC) {
+            // "Oops!!"
+            (void)"おおっと！！ (%08x %08x)\n";
+
+            err = 1;
+            break;
+        }
+    }
+
+    // "The arena still looks good"
+    (void)"アリーナはまだ、いけそうです\n";
+
+    ArenaImpl_Unlock(arena);
+
+    return err;
+}
diff --git a/src/boot_O2/boot_800862E0.c b/src/boot_O2/boot_800862E0.c
index ecba8c5f54..1055dfe1b8 100644
--- a/src/boot_O2/boot_800862E0.c
+++ b/src/boot_O2/boot_800862E0.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "os_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/boot/boot_800862E0/SystemArena_MallocMin1.s")
 
diff --git a/src/boot_O2/loadfragment.c b/src/boot_O2/loadfragment.c
index 4589cd3590..968fb464ab 100644
--- a/src/boot_O2/loadfragment.c
+++ b/src/boot_O2/loadfragment.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/boot/loadfragment/Load_Relocate.s")
 
diff --git a/src/boot_O2/loadfragment2.c b/src/boot_O2/loadfragment2.c
index 5c884be962..c324b80d5c 100644
--- a/src/boot_O2/loadfragment2.c
+++ b/src/boot_O2/loadfragment2.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 UNK_TYPE4 D_80096C30 = 2;
 
diff --git a/src/boot_O2/system_malloc.c b/src/boot_O2/system_malloc.c
index ad2bb63458..56608166cb 100644
--- a/src/boot_O2/system_malloc.c
+++ b/src/boot_O2/system_malloc.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "os_malloc.h"
 
 Arena gSystemArena;
 
@@ -29,8 +30,8 @@ void* SystemArena_Calloc(u32 elements, size_t size) {
     return ptr;
 }
 
-void SystemArena_AnalyzeArena(size_t* maxFreeBlock, size_t* bytesFree, size_t* bytesAllocated) {
-    __osAnalyzeArena(&gSystemArena, maxFreeBlock, bytesFree, bytesAllocated);
+void SystemArena_GetSizes(size_t* maxFreeBlock, size_t* bytesFree, size_t* bytesAllocated) {
+    __osGetSizes(&gSystemArena, maxFreeBlock, bytesFree, bytesAllocated);
 }
 
 u32 SystemArena_CheckArena(void) {
diff --git a/src/code/game.c b/src/code/game.c
index e431fafdaf..2713be2990 100644
--- a/src/code/game.c
+++ b/src/code/game.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 s32 gFramerateDivisor = 1;
 f32 gFramerateDivisorF = 1.0f;
@@ -174,7 +175,7 @@ void GameState_Realloc(GameState* gameState, size_t size) {
     alloc = &gameState->alloc;
     THA_Dt(&gameState->heap);
     GameAlloc_Free(alloc, heapStart);
-    SystemArena_AnalyzeArena(&systemMaxFree, &bytesFree, &bytesAllocated);
+    SystemArena_GetSizes(&systemMaxFree, &bytesFree, &bytesAllocated);
     size = ((systemMaxFree - (sizeof(ArenaNode))) < size) ? (0) : (size);
     if (size == 0) {
         size = systemMaxFree - (sizeof(ArenaNode));
diff --git a/src/code/gamealloc.c b/src/code/gamealloc.c
index 541f9125b0..6067ad91c4 100644
--- a/src/code/gamealloc.c
+++ b/src/code/gamealloc.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 void GameAlloc_Log(GameAlloc* this) {
     GameAllocEntry* iter;
diff --git a/src/code/graph.c b/src/code/graph.c
index e09cfedc4b..8059d1f63a 100644
--- a/src/code/graph.c
+++ b/src/code/graph.c
@@ -1,5 +1,6 @@
 #include "prevent_bss_reordering.h"
 #include "global.h"
+#include "system_malloc.h"
 #include "overlays/gamestates/ovl_daytelop/z_daytelop.h"
 #include "overlays/gamestates/ovl_file_choose/z_file_choose.h"
 #include "overlays/gamestates/ovl_opening/z_opening.h"
diff --git a/src/code/listalloc.c b/src/code/listalloc.c
index da294a1091..33f9989ba1 100644
--- a/src/code/listalloc.c
+++ b/src/code/listalloc.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 ListAlloc* ListAlloc_Init(ListAlloc* this) {
     this->prev = NULL;
diff --git a/src/code/speed_meter.c b/src/code/speed_meter.c
index b8b0299eba..9f04de110c 100644
--- a/src/code/speed_meter.c
+++ b/src/code/speed_meter.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/speed_meter/func_80177390.s")
 
diff --git a/src/code/sys_cmpdma.c b/src/code/sys_cmpdma.c
index c670645fc2..2533c44f5e 100644
--- a/src/code/sys_cmpdma.c
+++ b/src/code/sys_cmpdma.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/sys_cmpdma/func_80178750.s")
 
diff --git a/src/code/sys_flashrom.c b/src/code/sys_flashrom.c
index 1431e7a666..8b6c2fa5cc 100644
--- a/src/code/sys_flashrom.c
+++ b/src/code/sys_flashrom.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/sys_flashrom/func_801857C0.s")
 
diff --git a/src/code/z_DLF.c b/src/code/z_DLF.c
index 688a5af159..4c57aca014 100644
--- a/src/code/z_DLF.c
+++ b/src/code/z_DLF.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/z_DLF/Overlay_LoadGameState.s")
 
diff --git a/src/code/z_debug.c b/src/code/z_debug.c
index 924a2ad305..46649a4ce1 100644
--- a/src/code/z_debug.c
+++ b/src/code/z_debug.c
@@ -1,11 +1,12 @@
 #include "global.h"
+#include "system_malloc.h"
 
 GameInfo* gGameInfo;
 
 void GameInfo_Init(void) {
     s32 i;
 
-    gGameInfo = (GameInfo*)SystemArena_Malloc(sizeof(GameInfo));
+    gGameInfo = SystemArena_Malloc(sizeof(GameInfo));
     if (1) {}
     gGameInfo->unk_00 = 0;
     gGameInfo->unk_01 = 0;
diff --git a/src/code/z_fbdemo.c b/src/code/z_fbdemo.c
index c2da6f9cef..3d33399e58 100644
--- a/src/code/z_fbdemo.c
+++ b/src/code/z_fbdemo.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/z_fbdemo/func_80163DC0.s")
 
diff --git a/src/code/z_malloc.c b/src/code/z_malloc.c
index 8d0bba44ac..781f4310e8 100644
--- a/src/code/z_malloc.c
+++ b/src/code/z_malloc.c
@@ -1,4 +1,7 @@
 #include "global.h"
+#include "os_malloc.h"
+
+Arena sZeldaArena;
 
 void* ZeldaArena_Malloc(size_t size) {
     void* ptr = __osMalloc(&sZeldaArena, size);
@@ -34,11 +37,11 @@ void* ZeldaArena_Calloc(u32 num, size_t size) {
 }
 
 void ZeldaArena_GetSizes(size_t* outMaxFree, size_t* outFree, size_t* outAlloc) {
-    __osAnalyzeArena(&sZeldaArena, outMaxFree, outFree, outAlloc);
+    __osGetSizes(&sZeldaArena, outMaxFree, outFree, outAlloc);
 }
 
-void ZeldaArena_Check() {
-    __osCheckArena(&sZeldaArena);
+s32 ZeldaArena_Check() {
+    return __osCheckArena(&sZeldaArena);
 }
 
 void ZeldaArena_Init(void* start, size_t size) {
diff --git a/src/code/z_vismono.c b/src/code/z_vismono.c
index 4e02a0af2c..6c0d1ef223 100644
--- a/src/code/z_vismono.c
+++ b/src/code/z_vismono.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "system_malloc.h"
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/z_vismono/func_801418B0.s")
 
diff --git a/src/overlays/actors/ovl_Eff_Dust/z_eff_dust.c b/src/overlays/actors/ovl_Eff_Dust/z_eff_dust.c
index 296d6e429f..697ea58e8f 100644
--- a/src/overlays/actors/ovl_Eff_Dust/z_eff_dust.c
+++ b/src/overlays/actors/ovl_Eff_Dust/z_eff_dust.c
@@ -5,6 +5,7 @@
  */
 
 #include "z_eff_dust.h"
+#include "system_malloc.h"
 
 #define FLAGS 0x00000030
 
diff --git a/tools/disasm/functions.txt b/tools/disasm/functions.txt
index 7466934fb9..69ca079a9b 100644
--- a/tools/disasm/functions.txt
+++ b/tools/disasm/functions.txt
@@ -204,7 +204,7 @@
     0x80086E20:("SystemArena_Realloc",),
     0x80086E50:("SystemArena_Free",),
     0x80086E78:("SystemArena_Calloc",),
-    0x80086ECC:("SystemArena_AnalyzeArena",),
+    0x80086ECC:("SystemArena_GetSizes",),
     0x80086F04:("SystemArena_CheckArena",),
     0x80086F28:("SystemArena_InitArena",),
     0x80086F58:("SystemArena_Cleanup",),
@@ -222,14 +222,14 @@
     0x800871B4:("ArenaImpl_Unlock",),
     0x800871DC:("ArenaImpl_GetLastBlock",),
     0x8008720C:("__osMallocInit",),
-    0x8008725C:("__osMallocAddBlock",),
+    0x8008725C:("__osMallocAddHeap",),
     0x800872FC:("__osMallocCleanup",),
     0x8008731C:("__osMallocIsInitalized",),
     0x80087324:("__osMalloc",),
     0x80087408:("__osMallocR",),
     0x800874EC:("__osFree",),
     0x800875E4:("__osRealloc",),
-    0x80087714:("__osAnalyzeArena",),
+    0x80087714:("__osGetSizes",),
     0x800877C4:("__osCheckArena",),
     0x80087830:("proutSprintf",),
     0x80087854:("vsprintf",),
diff --git a/tools/sizes/boot_functions.csv b/tools/sizes/boot_functions.csv
index 46e57b75c8..3685e3fa9c 100644
--- a/tools/sizes/boot_functions.csv
+++ b/tools/sizes/boot_functions.csv
@@ -201,7 +201,7 @@ asm/non_matchings/boot/system_malloc/SystemArena_MallocR.s,SystemArena_MallocR,0
 asm/non_matchings/boot/system_malloc/SystemArena_Realloc.s,SystemArena_Realloc,0x80086E20,0xC
 asm/non_matchings/boot/system_malloc/SystemArena_Free.s,SystemArena_Free,0x80086E50,0xA
 asm/non_matchings/boot/system_malloc/SystemArena_Calloc.s,SystemArena_Calloc,0x80086E78,0x15
-asm/non_matchings/boot/system_malloc/SystemArena_AnalyzeArena.s,SystemArena_AnalyzeArena,0x80086ECC,0xE
+asm/non_matchings/boot/system_malloc/SystemArena_GetSizes.s,SystemArena_GetSizes,0x80086ECC,0xE
 asm/non_matchings/boot/system_malloc/SystemArena_CheckArena.s,SystemArena_CheckArena,0x80086F04,0x9
 asm/non_matchings/boot/system_malloc/SystemArena_InitArena.s,SystemArena_InitArena,0x80086F28,0xC
 asm/non_matchings/boot/system_malloc/SystemArena_Cleanup.s,SystemArena_Cleanup,0x80086F58,0x9
@@ -219,14 +219,14 @@ asm/non_matchings/boot/__osMalloc/ArenaImpl_Lock.s,ArenaImpl_Lock,0x8008718C,0xA
 asm/non_matchings/boot/__osMalloc/ArenaImpl_Unlock.s,ArenaImpl_Unlock,0x800871B4,0xA
 asm/non_matchings/boot/__osMalloc/ArenaImpl_GetLastBlock.s,ArenaImpl_GetLastBlock,0x800871DC,0xC
 asm/non_matchings/boot/__osMalloc/__osMallocInit.s,__osMallocInit,0x8008720C,0x14
-asm/non_matchings/boot/__osMalloc/__osMallocAddBlock.s,__osMallocAddBlock,0x8008725C,0x28
+asm/non_matchings/boot/__osMalloc/__osMallocAddHeap.s,__osMallocAddHeap,0x8008725C,0x28
 asm/non_matchings/boot/__osMalloc/__osMallocCleanup.s,__osMallocCleanup,0x800872FC,0x8
 asm/non_matchings/boot/__osMalloc/__osMallocIsInitalized.s,__osMallocIsInitalized,0x8008731C,0x2
 asm/non_matchings/boot/__osMalloc/__osMalloc.s,__osMalloc,0x80087324,0x39
 asm/non_matchings/boot/__osMalloc/__osMallocR.s,__osMallocR,0x80087408,0x39
 asm/non_matchings/boot/__osMalloc/__osFree.s,__osFree,0x800874EC,0x3E
 asm/non_matchings/boot/__osMalloc/__osRealloc.s,__osRealloc,0x800875E4,0x4C
-asm/non_matchings/boot/__osMalloc/__osAnalyzeArena.s,__osAnalyzeArena,0x80087714,0x2C
+asm/non_matchings/boot/__osMalloc/__osGetSizes.s,__osGetSizes,0x80087714,0x2C
 asm/non_matchings/boot/__osMalloc/__osCheckArena.s,__osCheckArena,0x800877C4,0x1B
 asm/non_matchings/boot/sprintf/proutSprintf.s,proutSprintf,0x80087830,0x9
 asm/non_matchings/boot/sprintf/vsprintf.s,vsprintf,0x80087854,0x14