diff --git a/arm9/arm9.lsf b/arm9/arm9.lsf
index 8287f1338..74e31f797 100644
--- a/arm9/arm9.lsf
+++ b/arm9/arm9.lsf
@@ -358,6 +358,7 @@ Static arm9
 	### Nitro System SDK ###
 	Object NNS_FND_list.o
 	Object NNS_FND_heapcommon.o
+	Object NNS_FND_expheap_s.o
 	Object NNS_FND_expheap.o
 	Object NNS_FND_frameheap.o
 	Object NNS_FND_allocator.o
diff --git a/arm9/asm/NNS_FND_expheap.s b/arm9/asm/NNS_FND_expheap_s.s
similarity index 89%
rename from arm9/asm/NNS_FND_expheap.s
rename to arm9/asm/NNS_FND_expheap_s.s
index e94dba383..54a26a2f7 100644
--- a/arm9/asm/NNS_FND_expheap.s
+++ b/arm9/asm/NNS_FND_expheap_s.s
@@ -2,6 +2,10 @@
 	.include "global.inc"
 	.extern NNSi_FndInitHeapHead
 	.extern NNSi_FndFinalizeHeap
+	.extern GetRegionOfMBlock
+	.extern RemoveMBlock
+	.extern InsertMBlock
+	.extern InitMBlock
 	.text
 
 	arm_func_start NNS_FndGetSizeForMBlockExpHeap
@@ -520,64 +524,3 @@ InitExpHeap: ; 0x020AE420
 _020AE498: .word 0x45585048
 _020AE49C: .word 0x00004652
 	arm_func_end InitExpHeap
-
-	arm_func_start InitMBlock
-InitMBlock: ; 0x020AE4A0
-	ldr r3, [r0, #0x0]
-	mov r2, #0x0
-	strh r1, [r3, #0x0]
-	strh r2, [r3, #0x2]
-	ldr r1, [r0, #0x4]
-	add r0, r3, #0x10
-	sub r0, r1, r0
-	str r0, [r3, #0x4]
-	str r2, [r3, #0x8]
-	mov r0, r3
-	str r2, [r3, #0xc]
-	bx lr
-	arm_func_end InitMBlock
-
-	arm_func_start InsertMBlock
-InsertMBlock: ; 0x020AE4D0
-	str r2, [r1, #0x8]
-	cmp r2, #0x0
-	ldrne r3, [r2, #0xc]
-	strne r1, [r2, #0xc]
-	ldreq r3, [r0, #0x0]
-	streq r1, [r0, #0x0]
-	str r3, [r1, #0xc]
-	cmp r3, #0x0
-	strne r1, [r3, #0x8]
-	streq r1, [r0, #0x4]
-	mov r0, r1
-	bx lr
-	arm_func_end InsertMBlock
-
-	arm_func_start RemoveMBlock
-RemoveMBlock: ; 0x020AE500
-	ldr r2, [r1, #0x8]
-	ldr r1, [r1, #0xc]
-	cmp r2, #0x0
-	strne r1, [r2, #0xc]
-	streq r1, [r0, #0x0]
-	cmp r1, #0x0
-	strne r2, [r1, #0x8]
-	streq r2, [r0, #0x4]
-	mov r0, r2
-	bx lr
-	arm_func_end RemoveMBlock
-
-	arm_func_start GetRegionOfMBlock
-GetRegionOfMBlock: ; 0x020AE528
-	ldrh r2, [r1, #0x2]
-	add r3, r1, #0x10
-	mov r2, r2, asr #0x8
-	and r2, r2, #0x7f
-	mov r2, r2, lsl #0x10
-	sub r2, r1, r2, lsr #0x10
-	str r2, [r0, #0x0]
-	ldr r1, [r1, #0x4]
-	add r1, r1, r3
-	str r1, [r0, #0x4]
-	bx lr
-	arm_func_end GetRegionOfMBlock
diff --git a/arm9/lib/libnns/include/NNS_FND_heapcommon.h b/arm9/lib/libnns/include/NNS_FND_heapcommon.h
index e6fab69c8..8128e74bd 100644
--- a/arm9/lib/libnns/include/NNS_FND_heapcommon.h
+++ b/arm9/lib/libnns/include/NNS_FND_heapcommon.h
@@ -7,6 +7,18 @@
 
 typedef struct NNSiFndHeapHead NNSiFndHeapHead;
 
+typedef s32 NNSiIntPtr;
+typedef u32 NNSiUIntPtr;
+
+#define NNSi_FndGetBitValue(data, st, bits) (((data) >>(st)) & ((1 <<(bits)) -1))
+#define NNSi_FndSetBitValue(data, st, bits, val) do { \
+    u32 maskBits = (u32)((1 << (bits)) - 1);          \
+    u32 newVal = (val) & maskBits;                    \
+    (void)(maskBits <<= st);                          \
+    (data) &= ~maskBits;                              \
+    (data) |= newVal << (st);                         \
+} while (FALSE);
+
 struct NNSiFndHeapHead
 {
     u32             signature;
@@ -23,4 +35,56 @@ struct NNSiFndHeapHead
 
 typedef NNSiFndHeapHead* NNSFndHeapHandle;   // Type to represent heap handle
 
+static inline NNSiUIntPtr NNSiGetUIntPtr(const void* ptr)
+{
+    return (NNSiUIntPtr)ptr;
+}
+
+static inline u32 GetOffsetFromPtr(const void* start, const void* end)
+{
+    return NNSiGetUIntPtr(end) - NNSiGetUIntPtr(start);
+}
+
+static inline void* AddU32ToPtr(void* ptr, u32 val)
+{
+    return (void*)( NNSiGetUIntPtr(ptr) + val );
+}
+
+static inline const void* AddU32ToCPtr(const void* ptr, u32 val)
+{
+    return (const void*)( NNSiGetUIntPtr(ptr) + val );
+}
+
+static inline void* SubU32ToPtr(void* ptr, u32 val)
+{
+    return (void*)(NNSiGetUIntPtr(ptr) - val);
+}
+
+static inline const void* SubU32ToCPtr(const void* ptr, u32 val)
+{
+    return (const void*)(NNSiGetUIntPtr(ptr) - val);
+}
+
+static inline int ComparePtr(const void* a, const void* b)
+{
+    const u8* wa = a;
+    const u8* wb = b;
+
+    return wa - wb;
+}
+
+
+static inline u16 GetOptForHeap(const NNSiFndHeapHead* pHeapHd)
+{
+    return (u16)NNSi_FndGetBitValue(pHeapHd->attribute, 0, 8);
+}
+
+static inline void SetOptForHeap(
+    NNSiFndHeapHead*    pHeapHd,
+    u16                 optFlag
+    )
+{
+    NNSi_FndSetBitValue(pHeapHd->attribute, 0, 8, optFlag);
+}
+
 #endif //GUARD_NNS_FND_HEAPCOMMON_H
diff --git a/arm9/lib/libnns/src/NNS_FND_expheap.c b/arm9/lib/libnns/src/NNS_FND_expheap.c
new file mode 100644
index 000000000..70e3886ac
--- /dev/null
+++ b/arm9/lib/libnns/src/NNS_FND_expheap.c
@@ -0,0 +1,92 @@
+#include "global.h"
+#include "NNS_FND_expheap.h"
+
+typedef struct NNSiMemRegion {
+    void* start;
+    void* end;
+} NNSiMemRegion;
+
+static inline u16 GetAlignmentForMBlock(NNSiFndExpHeapMBlockHead* block)
+{
+    return NNSi_FndGetBitValue(block->attribute, 8, 7);
+}
+
+static inline void* GetMemPtrForMBlock(NNSiFndExpHeapMBlockHead* block)
+{
+    return AddU32ToPtr(block, sizeof(NNSiFndExpHeapMBlockHead));
+}
+
+static inline void* GetMBlockEndAddr(NNSiFndExpHeapMBlockHead* block)
+{
+    return AddU32ToPtr(GetMemPtrForMBlock(block), block->blockSize);
+}
+
+void GetRegionOfMBlock(NNSiMemRegion* region, NNSiFndExpHeapMBlockHead* block)
+{
+    region->start = SubU32ToPtr(block, GetAlignmentForMBlock(block));
+    region->end = GetMBlockEndAddr(block);
+}
+
+NNSiFndExpHeapMBlockHead* RemoveMBlock(NNSiFndExpMBlockList* list, NNSiFndExpHeapMBlockHead* block)
+{
+    NNSiFndExpHeapMBlockHead* const prev = block->pMBHeadPrev;
+    NNSiFndExpHeapMBlockHead* const next = block->pMBHeadNext;
+
+    if (prev != NULL)
+    {
+        prev->pMBHeadNext = next;
+    }
+    else
+    {
+        list->head = next;
+    }
+
+    if (next != NULL)
+    {
+        next->pMBHeadPrev = prev;
+    }
+    else
+    {
+        list->tail = prev;
+    }
+
+    return prev;
+}
+
+NNSiFndExpHeapMBlockHead* InsertMBlock(NNSiFndExpMBlockList* list, NNSiFndExpHeapMBlockHead* target, NNSiFndExpHeapMBlockHead* prev)
+{
+    NNSiFndExpHeapMBlockHead* next;
+    target->pMBHeadPrev = prev;
+    if (prev != NULL)
+    {
+        next = prev->pMBHeadNext;
+        prev->pMBHeadNext = target;
+    }
+    else
+    {
+        next = list->head;
+        list->head = target;
+    }
+    target->pMBHeadNext = next;
+    if (next != NULL)
+    {
+        next->pMBHeadPrev = target;
+    }
+    else
+    {
+        list->tail = target;
+    }
+
+    return target;
+}
+
+NNSiFndExpHeapMBlockHead* InitMBlock(const NNSiMemRegion* pRegion, u16 signature)
+{
+    NNSiFndExpHeapMBlockHead* block = pRegion->start;
+    block->signature = signature;
+    block->attribute = 0;
+    block->blockSize = GetOffsetFromPtr(GetMemPtrForMBlock(block), pRegion->end);
+    block->pMBHeadPrev = NULL;
+    block->pMBHeadNext = NULL;
+    return block;
+}
diff --git a/arm9/lib/libnns/src/NNS_FND_heapcommon.c b/arm9/lib/libnns/src/NNS_FND_heapcommon.c
index 664007f15..07b8e9cf7 100644
--- a/arm9/lib/libnns/src/NNS_FND_heapcommon.c
+++ b/arm9/lib/libnns/src/NNS_FND_heapcommon.c
@@ -5,12 +5,6 @@
 BOOL sRootListInitialized;
 NNSFndList sRootList;
 
-static inline void NNSi_FndHeapHeadSetOptionFlag(NNSiFndHeapHead *pHead, u8 option_flag)
-{
-    pHead->attribute &= ~0xFF;
-    pHead->attribute |= option_flag;
-}
-
 void *NNS_FndGetNextListObject(NNSFndList *, void *);
 
 static NNSiFndHeapHead* FindContainHeap(NNSFndList * pList, const void * memBlock)
@@ -45,7 +39,7 @@ void NNSi_FndInitHeapHead(NNSiFndHeapHead *pHead, u32 signature, void* heapStart
     pHead->heapStart = heapStart;
     pHead->heapEnd = heapEnd;
     pHead->attribute = 0;
-    NNSi_FndHeapHeadSetOptionFlag(pHead, optionFlag);
+    SetOptForHeap(pHead, optionFlag);
     NNS_FndInitList(&pHead->childList, 4);
     if (!sRootListInitialized)
     {