diff --git a/include/msm/msmfio.h b/include/msm/msmfio.h
new file mode 100644
index 00000000..2335134f
--- /dev/null
+++ b/include/msm/msmfio.h
@@ -0,0 +1,19 @@
+#ifndef MSMFIO_H
+#define MSMFIO_H
+
+#include "dolphin.h"
+#include "dolphin/types.h"
+#include "game/msm.h"
+
+struct msmFio {
+    MSM_OPEN open;
+    MSM_READ read;
+    MSM_CLOSE close;
+};
+
+BOOL msmFioClose(DVDFileInfo *fileInfo);
+BOOL msmFioRead(DVDFileInfo *fileInfo, void *addr, s32 length, s32 offset);
+BOOL msmFioOpen(s32 entrynum, DVDFileInfo *fileInfo);
+void msmFioInit(MSM_OPEN open, MSM_READ read, MSM_CLOSE close);
+
+#endif
diff --git a/include/msm/msmmem.h b/include/msm/msmmem.h
index ca14b0c9..1acc500a 100644
--- a/include/msm/msmmem.h
+++ b/include/msm/msmmem.h
@@ -3,8 +3,8 @@
 
 #include "dolphin/types.h"
 
-void msmMemFree(void*);
-void* msmMemAlloc(s32);
-void msmMemInit(void*, u32);
+void msmMemFree(void *);
+void *msmMemAlloc(u32);
+void msmMemInit(void *, u32);
 
 #endif
diff --git a/include/msm/msmmus.h b/include/msm/msmmus.h
new file mode 100644
index 00000000..8d3554fc
--- /dev/null
+++ b/include/msm/msmmus.h
@@ -0,0 +1,10 @@
+#ifndef MSMMUS_H
+#define MSMMUS_H
+
+#include "dolphin.h"
+#include "dolphin/types.h"
+
+s32 msmMusInit(s32 *, DVDFileInfo *);
+void msmMusPeriodicProc(void);
+
+#endif
diff --git a/include/msm/msmse.h b/include/msm/msmse.h
new file mode 100644
index 00000000..10242362
--- /dev/null
+++ b/include/msm/msmse.h
@@ -0,0 +1,10 @@
+#ifndef MSMSE_H
+#define MSMSE_H
+
+#include "dolphin.h"
+#include "dolphin/types.h"
+
+s32 msmSeInit(s32 *, DVDFileInfo *);
+void msmSePeriodicProc(void);
+
+#endif
diff --git a/include/msm/msmstream.h b/include/msm/msmstream.h
new file mode 100644
index 00000000..c21347b0
--- /dev/null
+++ b/include/msm/msmstream.h
@@ -0,0 +1,12 @@
+#ifndef MSMSTREAM_H
+#define MSMSTREAM_H
+
+#include "dolphin/types.h"
+
+void msmStreamPeriodicProc(void);
+void msmStreamSetOutputMode(s8);
+void msmStreamAmemFree(void);
+s32 msmStreamAmemAlloc(void);
+s32 msmStreamInit(char *);
+
+#endif
diff --git a/src/msm/msmfio.c b/src/msm/msmfio.c
index 581cb3a1..00adc985 100644
--- a/src/msm/msmfio.c
+++ b/src/msm/msmfio.c
@@ -1,43 +1,41 @@
-#include "dolphin.h"
-
-struct msmFio {
-	BOOL (*open)(s32, DVDFileInfo *);
-	BOOL (*read)(DVDFileInfo *, void *, s32, s32, s32);
-	BOOL (*close)(DVDFileInfo *);
-};
+#include "msm/msmfio.h"
+#include "game/msm.h"
 
 static struct msmFio fio;
 
 BOOL msmFioClose(DVDFileInfo *fileInfo)
 {
-	return fio.close(fileInfo);
+    return fio.close(fileInfo);
 }
 
 BOOL msmFioRead(DVDFileInfo *fileInfo, void *addr, s32 length, s32 offset)
 {
-	return fio.read(fileInfo, addr, length, offset, 2);
+    return fio.read(fileInfo, addr, length, offset, 2);
 }
 
 BOOL msmFioOpen(s32 entrynum, DVDFileInfo *fileInfo)
 {
-	return fio.open(entrynum, fileInfo);
+    return fio.open(entrynum, fileInfo);
 }
 
-void msmFioInit(void *open, void *read, void *close)
+void msmFioInit(MSM_OPEN open, MSM_READ read, MSM_CLOSE close)
 {
-	if(open) {
-		fio.open = open;
-	} else {
-		fio.open = DVDFastOpen;
-	}
-	if(read) {
-		fio.read = read;
-	} else {
-		fio.read = DVDReadPrio;
-	}
-	if(close) {
-		fio.close = close;
-	} else {
-		fio.close = DVDClose;
-	}
-}
\ No newline at end of file
+    if (open) {
+        fio.open = open;
+    }
+    else {
+        fio.open = DVDFastOpen;
+    }
+    if (read) {
+        fio.read = read;
+    }
+    else {
+        fio.read = DVDReadPrio;
+    }
+    if (close) {
+        fio.close = close;
+    }
+    else {
+        fio.close = DVDClose;
+    }
+}
diff --git a/src/msm/msmmem.c b/src/msm/msmmem.c
index b89434a0..e8d52a88 100644
--- a/src/msm/msmmem.c
+++ b/src/msm/msmmem.c
@@ -53,7 +53,7 @@ void msmMemFree(void* arg0) {
     }
 }
 
-void* msmMemAlloc(s32 arg0) {
+void* msmMemAlloc(u32 arg0) {
     unkMemStruct* memC;
     s32 temp_r0;
     u32 var_r5;
@@ -87,7 +87,7 @@ void* msmMemAlloc(s32 arg0) {
     if (var_r5 != 0) {
         var_r5 -= 0x20;
     }
-    temp_r5 = (void*)((u32)var_r8->unk10 + var_r5);
+    temp_r5 = (void*)((u32)var_r8->unk10 + (var_r5));
     temp_r9 = var_r8->next;
     if ((mem.unk0 > temp_r5) || ((void*)((u32)mem.unk0 + (u32)mem.unk4) <= temp_r5)) {
         return NULL;
@@ -133,4 +133,4 @@ void msmMemInit(void* arg0, u32 arg1) {
     temp_r7->prev = NULL;
     temp_r7->next = NULL;
     mem.unk8 = &mem.unkC;
-}
\ No newline at end of file
+}
diff --git a/src/msm/msmsys.c b/src/msm/msmsys.c
new file mode 100644
index 00000000..9c9aedda
--- /dev/null
+++ b/src/msm/msmsys.c
@@ -0,0 +1,442 @@
+#include "dolphin.h"
+#include "dolphin/ai.h"
+#include "msm/msmfio.h"
+#include "msm/msmmem.h"
+#include "msm/msmmus.h"
+#include "msm/msmse.h"
+#include "msm/msmstream.h"
+#include "musyx/musyx.h"
+
+#include "game/msm.h" // TODO remove, only for decomp
+
+typedef struct _unkSubStruct {
+    s8 unk0;
+    union {
+        f32 unk4f[9];
+        s32 unk4s[9];
+    };
+} unkSubStruct;
+
+typedef struct _unkSubStruct2 {
+    char unk[0x3C];
+    s32 unk3C;
+    s32 unk40;
+    s32 unk44;
+    s32 unk48;
+    s32 unk4C;
+    s32 unk50;
+    s32 unk54;
+    s32 unk58;
+    s32 unk5C;
+    char unk60[0x30];
+    s32 unk90;
+    s32 unk94;
+    s32 unk98;
+    char unk9C[0xA0];
+    u8 unk13C;
+    f32 unk140;
+    f32 unk144;
+    f32 unk148;
+    f32 unk14C;
+    f32 unk150;
+    char unk154[0x70];
+    u8 unk1C4;
+    f32 unk1C8;
+    f32 unk1CC;
+    f32 unk1D0;
+    f32 unk1D4;
+    f32 unk1D8;
+    f32 unk1DC;
+} unkSubStruct2; // sizeof unk1E0
+
+typedef struct _unkSubStruct3 {
+    char unk[0x4];
+    s32 unk4;
+    char unk8[0x8];
+    s32 unk10; // offset
+    u32 unk14; // length
+    s32 unk18; // offset
+    u32 unk1C; // length
+    char unk20[0x18];
+    s32 unk38;
+    char unk3C[4];
+    s32 unk40;
+    char unk44[0x1C];
+} unkSubStruct3; // sizeof 0x60
+
+typedef struct _unkStruct2 {
+    char *unk0;
+    s32 unk4;
+    void *unk8;
+    void *unkC;
+    void *unk10;
+    u32 unk14;
+    void *unk18;
+} unkStruct2;
+
+typedef struct _unkStruct3 {
+    s32 unk0;
+    s32 unk4;
+    s32 unk8;
+} unkStruct3;
+
+typedef struct _unkStruct4 {
+    SND_GROUPID unk0;
+    s32 unk4;
+    s32 unk8;
+    s32 unkC;
+    s32 unk10;
+} unkStruct4;
+
+typedef struct _sndInitData {
+    s8 unk0;
+    s8 unk1;
+    s8 unk2;
+    char unk3[0xB];
+    s8 unkE;
+    s8 unkF;
+    u32 unk10;
+    s32 unk14;
+    char unk18[0x11];
+    s8 unk29[10]; // size unknown
+} sndInitData;
+
+typedef struct _sysData {
+    s32 unk0;
+    s8 unk4;
+    s8 unk5;
+    s8 unk6;
+    s8 unk7;
+    s32 unk8;
+    unkSubStruct3 *unkC;
+    sndInitData *unk10;
+    unkSubStruct *unk14;
+    s8 unk18;
+    s8 unk19;
+    s8 unk1A;
+    s8 unk1B;
+    unkSubStruct2 unk1C; // userA
+    unkSubStruct2 unk1FC; // userB
+    char unk3DC[0x8];
+    s32 unk3E4;
+    s32 unk3E8;
+    s32 unk3EC;
+    s32 unk3F0;
+    s8 unk3F4;
+    unkStruct3 *unk3F8;
+    char unk3FC[0xF0];
+    s32 unk4EC;
+    BOOL unk4F0;
+    AIDCallback unk4F4;
+    s32 unk4F8;
+} sysData;
+
+static sysData sys;
+
+void msmSysServer(void)
+{
+    if (sndIsInstalled() == 1) {
+        if (--sys.unk4F8 == 0) {
+            sys.unk4F8 = 3;
+            msmMusPeriodicProc();
+            msmSePeriodicProc();
+            msmStreamPeriodicProc();
+        }
+    }
+    sys.unk4F4();
+}
+
+s32 msmSysSetAuxParam(s32 arg0, s32 arg1)
+{
+    SND_AUX_CALLBACK sp24;
+    SND_AUX_CALLBACK sp20;
+    void **var_r26;
+    s32 var_r23;
+    unkSubStruct2 *temp_r3;
+    sysData *var_r25;
+    sysData *var_r27;
+    unkSubStruct *temp_r5;
+    u32 var_r0;
+    u8 temp_r5_2;
+    unkSubStruct *temp_r4_2;
+
+    if ((sys.unk18 != -2) && (arg0 >= 0)) {
+        sys.unk18 = arg0;
+    }
+    if ((sys.unk19 != -2) && (arg1 >= 0)) {
+        temp_r5->unk0 = arg1;
+    }
+    if ((sys.unk18 < 0) && (temp_r5->unk0 < 0)) {
+        return 0;
+    }
+    var_r27 = &sys;
+    var_r25 = &sys;
+    var_r26 = &sp20;
+
+    // the for loop first sets sp20 and then sp24
+    for (var_r23 = 0; var_r23 < 2; var_r23++, var_r27++, var_r26++, var_r25++) {
+        if (var_r27->unk18 < 0) {
+            *var_r26 = NULL;
+            continue;
+        }
+        temp_r4_2 = &sys.unk14[var_r27->unk18];
+        temp_r3 = &var_r25->unk1C;
+        switch (temp_r4_2->unk0) {
+            case 0:
+                *var_r26 = &sndAuxCallbackReverbHI;
+                temp_r3->unk1C4 = temp_r4_2->unk4s[0];
+                temp_r3->unk1C8 = temp_r4_2->unk4f[1];
+                temp_r3->unk1CC = temp_r4_2->unk4f[2];
+                temp_r3->unk1D0 = temp_r4_2->unk4f[3];
+                temp_r3->unk1D4 = temp_r4_2->unk4f[4];
+                temp_r3->unk1D8 = temp_r4_2->unk4f[5];
+                temp_r3->unk1DC = temp_r4_2->unk4f[6];
+                // var_r0 = sndAuxCallbackPrepareReverbHI();
+                break;
+            case 1:
+                *var_r26 = &sndAuxCallbackReverbSTD;
+                temp_r3->unk13C = temp_r4_2->unk4s[0];
+                temp_r3->unk140 = temp_r4_2->unk4f[1];
+                temp_r3->unk144 = temp_r4_2->unk4f[2];
+                temp_r3->unk148 = temp_r4_2->unk4f[3];
+                temp_r3->unk14C = temp_r4_2->unk4f[4];
+                temp_r3->unk150 = temp_r4_2->unk4f[5];
+                // var_r0 = sndAuxCallbackPrepareReverbSTD();
+                break;
+            case 2:
+                *var_r26 = &sndAuxCallbackChorus;
+                temp_r3->unk90 = temp_r4_2->unk4s[0];
+                temp_r3->unk94 = temp_r4_2->unk4s[1];
+                temp_r3->unk98 = temp_r4_2->unk4s[2];
+                // var_r0 = sndAuxCallbackPrepareChorus();
+                break;
+            case 3:
+                *var_r26 = &sndAuxCallbackDelay;
+                temp_r3->unk3C = temp_r4_2->unk4s[0];
+                temp_r3->unk48 = temp_r4_2->unk4s[3];
+                temp_r3->unk54 = temp_r4_2->unk4s[6];
+                temp_r3->unk40 = temp_r4_2->unk4s[1];
+                temp_r3->unk4C = temp_r4_2->unk4s[4];
+                temp_r3->unk58 = temp_r4_2->unk4s[7];
+                temp_r3->unk44 = temp_r4_2->unk4s[2];
+                temp_r3->unk50 = temp_r4_2->unk4s[5];
+                temp_r3->unk5C = temp_r4_2->unk4s[8];
+                // var_r0 = sndAuxCallbackPrepareDelay();
+                break;
+        }
+        if (var_r0 == 0) {
+            return 1;
+        }
+    }
+    sndSetAuxProcessingCallbacks(0, sp20, &sys.unk1C, 0xFF, 0, sp24, &sys.unk1FC, 0xFF, 0);
+    return 0;
+}
+
+s8 msmSysLoadBaseGroup(void *arg0)
+{
+    DVDFileInfo spC;
+    sysData *var_r30;
+    s32 var_r28;
+    unkStruct3 *temp_r27;
+    unkStruct4 *temp_r25;
+
+    if (msmFioOpen(sys.unk0, &spC) != 1) {
+        return -1;
+    }
+    var_r30 = &sys;
+    for (var_r28 = 0; var_r28 < sys.unk3F4; var_r30 = (sysData *)((s32)var_r30 + 4), var_r28++, sys.unk8 += temp_r25->unk10) {
+        temp_r27 = var_r30->unk3F8;
+        temp_r25 = (unkStruct4 *)(sys.unk3EC + (sys.unk10->unk29[var_r28] << 5));
+        if (msmFioRead(&spC, temp_r27, temp_r25->unk8, temp_r25->unk4 + sys.unkC->unk38) < 0) {
+            msmFioClose(&spC);
+            return -2;
+        }
+        if (msmFioRead(&spC, arg0, temp_r25->unk10, temp_r25->unkC + sys.unkC->unk40) < 0) {
+            msmFioClose(&spC);
+            return -2;
+        }
+        if (sndPushGroup((void *)(temp_r27->unk4 + (s32)temp_r27), temp_r25->unk0, arg0, (void *)(temp_r27->unk8 + (s32)temp_r27),
+                (void *)(temp_r27->unk0 + (s32)temp_r27))
+            == 0U) {
+            msmFioClose(&spC);
+            return -0x20;
+        }
+    }
+    msmFioClose(&spC);
+    return 0;
+}
+
+s32 msmSysGroupInit(DVDFileInfo *arg0);
+
+void msmSysIrqDisable(void)
+{
+    if (sys.unk4EC++ == 0) {
+        sys.unk4F0 = OSDisableInterrupts();
+    }
+}
+
+void msmSysIrqEnable(void)
+{
+    if (sys.unk4EC != 0) {
+        if (--sys.unk4EC == 0) {
+            OSRestoreInterrupts(sys.unk4F0);
+        }
+    }
+}
+
+void msmSysRegularProc(void);
+
+s32 msmSysGetOutputMode(void)
+{
+    return sys.unk4;
+}
+
+s32 msmSysGetSampSize(BOOL baseGrp)
+{
+    if (baseGrp != 0) {
+        return sys.unk3E8;
+    }
+    return sys.unk3E4;
+}
+
+void msmSysCheckInit(void)
+{
+    sndIsInstalled();
+}
+
+s32 msmSysInit(MSM_INIT *init, MSM_ARAM *aram)
+{
+    s32 var_r26;
+    s32 temp_r3;
+    void *temp_r3_8;
+
+    SND_HOOKS sp4C = { msmMemAlloc, msmMemFree };
+    DVDFileInfo sp10;
+    if (sndIsInstalled() == 1) {
+        return -0x24;
+    }
+    var_r26 = 0; // retErr
+    sys.unk4EC = 0;
+    msmMemInit(init->heap, init->heapSize);
+    msmFioInit(init->open, init->read, init->close);
+    sys.unk0 = DVDConvertPathToEntrynum(init->msmPath);
+    if (sys.unk0 < 0) {
+        return -1;
+    }
+    if (msmFioOpen(sys.unk0, &sp10) != 1) {
+        return -1;
+    }
+    if ((sys.unkC = msmMemAlloc(0x60)) == NULL) {
+        msmFioClose(&sp10);
+        return -0xA;
+    }
+    if (msmFioRead(&sp10, sys.unkC, 0x60, 0) < 0) {
+        msmFioClose(&sp10);
+        return -2;
+    }
+    if (sys.unkC->unk4 != 2) {
+        msmFioClose(&sp10);
+        return -0x79;
+    }
+    if ((sys.unk10 = msmMemAlloc(sys.unkC->unk14)) == NULL) {
+        msmFioClose(&sp10);
+        return -0xA;
+    }
+    if (msmFioRead(&sp10, sys.unk10, sys.unkC->unk14, sys.unkC->unk10) < 0) {
+        msmFioClose(&sp10);
+        return -2;
+    }
+    if (aram != NULL) {
+        if (aram->skipARInit == 0) {
+            ARInit(aram->stackIndex, aram->aramEnd);
+            ARQInit();
+            aram = (MSM_ARAM *)ARAlloc(sys.unk10->unk14);
+            if ((u32)aram != ARGetBaseAddress()) {
+                msmFioClose(&sp10);
+                return -0x14;
+            }
+            sys.unk7 = 0;
+        }
+        else {
+            if ((sys.unk10->unk14 + ARGetBaseAddress()) > aram->aramEnd) {
+                msmFioClose(&sp10);
+                return -0x14;
+            }
+            ARInit(NULL, 0);
+            ARQInit();
+            sys.unk7 = 1;
+        }
+    }
+    var_r26 = msmSysGroupInit(&sp10);
+    if (var_r26 != 0) {
+        msmFioClose(&sp10);
+        return var_r26;
+    }
+    var_r26 = msmMusInit(&sys.unk0, &sp10);
+    if (var_r26 != 0) {
+        msmFioClose(&sp10);
+        return var_r26;
+    }
+    var_r26 = msmSeInit(&sys.unk0, &sp10);
+    if (var_r26 != 0) {
+        msmFioClose(&sp10);
+        return var_r26;
+    }
+    sys.unk18 = sys.unk10->unkE == -2 ? -2 : -1;
+    sys.unk19 = sys.unk10->unkF == -2 ? -2 : -1;
+    if ((s32)sys.unkC->unk1C == 0) {
+        var_r26 = 0;
+    }
+    else {
+        if ((sys.unk14 = msmMemAlloc(sys.unkC->unk1C)) == NULL) {
+            var_r26 = -0xA;
+        }
+        else {
+            if (msmFioRead(&sp10, sys.unk14, sys.unkC->unk1C, sys.unkC->unk18) < 0) {
+                var_r26 = -2;
+            }
+            else {
+                var_r26 = 0;
+            }
+        }
+    }
+    if (var_r26 != 0) {
+        msmFioClose(&sp10);
+        return var_r26;
+    }
+    msmFioClose(&sp10);
+    temp_r3 = msmStreamInit(init->pdtPath);
+    if (temp_r3 < 0) {
+        return temp_r3;
+    }
+    AIInit(NULL);
+    sndSetHooks(&sp4C);
+    if (sndInit(sys.unk10->unk0, sys.unk10->unk1, sys.unk10->unk2, 1, 0, sys.unk10->unk14) != 0) {
+        return -0x1E;
+    }
+    sys.unk4F4 = AIRegisterDMACallback(msmSysServer);
+    sys.unk4F8 = 1;
+    var_r26 = msmStreamAmemAlloc();
+    if (var_r26 < 0) {
+        sndQuit();
+        return var_r26;
+    }
+    sys.unk8 = var_r26 + 0x500;
+    if ((s32)sys.unk10->unk10 != 0) {
+        temp_r3_8 = msmMemAlloc(sys.unk10->unk10 + 0x100);
+        if (temp_r3_8 == NULL) {
+            msmStreamAmemFree();
+            sndQuit();
+            return -0xA;
+        }
+        msmMemFree(temp_r3_8);
+    }
+    if (msmSysSetAuxParam(sys.unk10->unkE, sys.unk10->unkF) != 0) {
+        msmStreamAmemFree();
+        sndQuit();
+        return -0x1F;
+    }
+    msmSysSetOutputMode(OSGetSoundMode() == 0 ? SND_OUTPUTMODE_MONO : SND_OUTPUTMODE_STEREO);
+    sndVolume(0x7F, 0, 0xFF);
+    return 0;
+}