diff --git a/Makefile b/Makefile
index 02ca4fbd52..e89dc19ea8 100644
--- a/Makefile
+++ b/Makefile
@@ -451,6 +451,9 @@ ifeq ($(PLATFORM),N64)
 $(BUILD_DIR)/src/code/z_rumble.o: CFLAGS += -DNO_SQRTF_INTRINSIC
 endif
 
+$(BUILD_DIR)/src/code/jpegutils.o: CC := $(CC_OLD)
+$(BUILD_DIR)/src/code/jpegdecoder.o: CC := $(CC_OLD)
+
 ifeq ($(DEBUG),1)
 $(BUILD_DIR)/src/libc/%.o: OPTFLAGS := -g
 else
@@ -470,28 +473,57 @@ endif
 $(BUILD_DIR)/src/audio/sfx.o: CFLAGS += -use_readwrite_const
 $(BUILD_DIR)/src/audio/sequence.o: CFLAGS += -use_readwrite_const
 
+$(BUILD_DIR)/src/libultra/%.o: CC := $(CC_OLD)
+
 $(BUILD_DIR)/src/libultra/libc/ll.o: OPTFLAGS := -O1
 $(BUILD_DIR)/src/libultra/libc/ll.o: MIPS_VERSION := -mips3 -32
 $(BUILD_DIR)/src/libultra/libc/llcvt.o: OPTFLAGS := -O1
 $(BUILD_DIR)/src/libultra/libc/llcvt.o: MIPS_VERSION := -mips3 -32
 
+ifeq ($(PLATFORM),N64)
+$(BUILD_DIR)/src/libultra/gu/%.o: OPTFLAGS := -O3
+$(BUILD_DIR)/src/libultra/io/%.o: OPTFLAGS := -O1
+$(BUILD_DIR)/src/libultra/libc/%.o: OPTFLAGS := -O3
 $(BUILD_DIR)/src/libultra/os/%.o: OPTFLAGS := -O1
+
+$(BUILD_DIR)/src/libultra/io/aisetfreq.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/cartrominit.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/contpfs.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/contramread.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/contramwrite.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/contreaddata.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/crc.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/devmgr.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/epiread.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/epiwrite.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/epirawdma.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/epirawread.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/epirawwrite.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/motor.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/pfsgetstatus.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/pfsselectbank.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/pimgr.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/pirawdma.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/sirawdma.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/sirawread.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/sirawwrite.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/sprawdma.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/vimgr.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/visetspecial.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/io/viswapcontext.o: OPTFLAGS := -O2
+
+$(BUILD_DIR)/src/libultra/gu/lookat.o: CFLAGS += -DNO_SQRTF_INTRINSIC
+$(BUILD_DIR)/src/libultra/gu/lookathil.o: CFLAGS += -DNO_SQRTF_INTRINSIC
+$(BUILD_DIR)/src/libultra/gu/normalize.o: CFLAGS += -DNO_SQRTF_INTRINSIC
+else
+$(BUILD_DIR)/src/libultra/gu/%.o: OPTFLAGS := -O2
 $(BUILD_DIR)/src/libultra/io/%.o: OPTFLAGS := -O2
 $(BUILD_DIR)/src/libultra/libc/%.o: OPTFLAGS := -O2
-$(BUILD_DIR)/src/libultra/rmon/%.o: OPTFLAGS := -O2
-$(BUILD_DIR)/src/libultra/gu/%.o: OPTFLAGS := -O2
+$(BUILD_DIR)/src/libultra/os/%.o: OPTFLAGS := -O1
+endif
 
 $(BUILD_DIR)/assets/misc/z_select_static/%.o: GBI_DEFINES := -DF3DEX_GBI
 
-$(BUILD_DIR)/src/libultra/gu/%.o: CC := $(CC_OLD)
-$(BUILD_DIR)/src/libultra/io/%.o: CC := $(CC_OLD)
-$(BUILD_DIR)/src/libultra/libc/%.o: CC := $(CC_OLD)
-$(BUILD_DIR)/src/libultra/os/%.o: CC := $(CC_OLD)
-$(BUILD_DIR)/src/libultra/rmon/%.o: CC := $(CC_OLD)
-
-$(BUILD_DIR)/src/code/jpegutils.o: CC := $(CC_OLD)
-$(BUILD_DIR)/src/code/jpegdecoder.o: CC := $(CC_OLD)
-
 # For using asm_processor on some files:
 #$(BUILD_DIR)/.../%.o: CC := $(PYTHON) tools/asm_processor/build.py $(CC) -- $(AS) $(ASFLAGS) --
 
diff --git a/include/functions.h b/include/functions.h
index 4efaf978fc..07a2201601 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -1677,7 +1677,7 @@ s32 __osCheckPackId(OSPfs* pfs, __OSPackId* check);
 s32 __osGetId(OSPfs* pfs);
 s32 __osCheckId(OSPfs* pfs);
 s32 __osPfsRWInode(OSPfs* pfs, __OSInode* inode, u8 flag, u8 bank);
-void guMtxL2F(MtxF* m1, Mtx* m2);
+void guMtxL2F(f32 mf[4][4], Mtx* m);
 s32 osPfsFindFile(OSPfs* pfs, u16 companyCode, u32 gameCode, u8* gameName, u8* extName, s32* fileNo);
 s32 osAfterPreNMI(void);
 s32 osContStartQuery(OSMesgQueue* mq);
@@ -1728,7 +1728,7 @@ u32 __osSpGetStatus(void);
 void __osSpSetStatus(u32 status);
 void osWritebackDCacheAll(void);
 OSThread* __osGetCurrFaultedThread(void);
-void guMtxF2L(MtxF* m1, Mtx* m2);
+void guMtxF2L(f32 mf[4][4], Mtx* m);
 // ? __d_to_ll(?);
 // ? __f_to_ll(?);
 // ? __d_to_ull(?);
diff --git a/include/ultra64/gu.h b/include/ultra64/gu.h
index 36ff2dd1c0..d0548b3a8d 100644
--- a/include/ultra64/gu.h
+++ b/include/ultra64/gu.h
@@ -5,6 +5,9 @@
 
 #define GU_PI 3.1415926
 
+#define FTOFIX32(x) (s32)((x) * (f32)0x00010000)
+#define FIX32TOF(x) ((f32)(x) * (1.0f / (f32)0x00010000))
+
 #define ROUND(x) (s32)(((x) >= 0.0) ? ((x) + 0.5) : ((x) - 0.5))
 
 typedef union du {
diff --git a/spec b/spec
index cf936194b6..afb1e9d389 100644
--- a/spec
+++ b/spec
@@ -589,7 +589,14 @@ beginseg
 #if OOT_DEBUG
     include "$(BUILD_DIR)/src/libultra/io/pfsfreeblocks.o"
 #endif
+#if PLATFORM_N64
+    include "$(BUILD_DIR)/src/libultra/os/getintmask.o"
+#endif
+#if PLATFORM_N64
+    include "$(BUILD_DIR)/src/libultra/gu/scale.o"
+#else
     include "$(BUILD_DIR)/src/libultra/mgu/scale.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/gu/sinf.o"
     include "$(BUILD_DIR)/src/libultra/gu/sins.o"
     include "$(BUILD_DIR)/src/libultra/io/sptask.o"
@@ -605,7 +612,12 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/io/pfsreadwritefile.o"
     include "$(BUILD_DIR)/src/libultra/io/pfsgetstatus.o"
 #endif
+#if PLATFORM_N64
+    include "$(BUILD_DIR)/src/libultra/gu/mtxutil.o"
+#endif
+#if !PLATFORM_N64
     include "$(BUILD_DIR)/src/libultra/mgu/mtxidentf.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/gu/lookat.o"
 #if OOT_DEBUG
     include "$(BUILD_DIR)/src/libultra/io/pfsallocatefile.o"
@@ -613,7 +625,9 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/os/stoptimer.o"
 #if OOT_DEBUG
     include "$(BUILD_DIR)/src/libultra/io/contpfs.o"
+#if !PLATFORM_N64
     include "$(BUILD_DIR)/src/libultra/mgu/mtxl2f.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/io/pfsfindfile.o"
 #endif
     include "$(BUILD_DIR)/src/libultra/gu/sqrtf.o"
@@ -627,13 +641,19 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/libc/string.o"
 #endif
     include "$(BUILD_DIR)/src/libultra/io/sp.o"
+#if !PLATFORM_N64
     include "$(BUILD_DIR)/src/libultra/mgu/mtxident.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/gu/position.o"
     include "$(BUILD_DIR)/src/libultra/io/sptaskyielded.o"
     include "$(BUILD_DIR)/src/libultra/gu/rotate.o"
     include "$(BUILD_DIR)/src/libultra/io/aisetfreq.o"
     include "$(BUILD_DIR)/src/libultra/os/getactivequeue.o"
+#if PLATFORM_N64
+    include "$(BUILD_DIR)/src/libultra/gu/normalize.o"
+#else
     include "$(BUILD_DIR)/src/libultra/mgu/normalize.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/io/dpgetstat.o"
     include "$(BUILD_DIR)/src/libultra/io/dpsetstat.o"
 #if OOT_DEBUG
@@ -643,6 +663,9 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/gu/cosf.o"
     include "$(BUILD_DIR)/src/libultra/gu/libm_vals.o"
     include "$(BUILD_DIR)/src/libultra/gu/coss.o"
+#if PLATFORM_N64
+    include "$(BUILD_DIR)/src/libultra/os/settime.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/io/visetevent.o"
 #if OOT_DEBUG
     include "$(BUILD_DIR)/src/libultra/io/pfsisplug.o"
@@ -656,7 +679,11 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/io/pfschecker.o"
 #endif
     include "$(BUILD_DIR)/src/libultra/io/aigetlen.o"
+#if PLATFORM_N64
+    include "$(BUILD_DIR)/src/libultra/gu/translate.o"
+#else
     include "$(BUILD_DIR)/src/libultra/mgu/translate.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/io/contramwrite.o"
 #if !OOT_DEBUG
     include "$(BUILD_DIR)/src/libultra/io/vimodefpallan1.o"
@@ -678,7 +705,9 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/io/spsetstat.o"
     include "$(BUILD_DIR)/src/libultra/os/writebackdcacheall.o"
     include "$(BUILD_DIR)/src/libultra/os/getcurrfaultedthread.o"
+#if !PLATFORM_N64
     include "$(BUILD_DIR)/src/libultra/mgu/mtxf2l.o"
+#endif
     include "$(BUILD_DIR)/src/libultra/libc/llcvt.o"
     include "$(BUILD_DIR)/src/libultra/io/vigetcurrframebuf.o"
     include "$(BUILD_DIR)/src/libultra/io/spsetpc.o"
diff --git a/src/code/mtxuty-cvt.c b/src/code/mtxuty-cvt.c
index 1cad0f9091..10f88f7827 100644
--- a/src/code/mtxuty-cvt.c
+++ b/src/code/mtxuty-cvt.c
@@ -20,5 +20,5 @@ void MtxConv_F2L(Mtx* m1, MtxF* m2) {
 void MtxConv_L2F(MtxF* m1, Mtx* m2) {
     LOG_UTILS_CHECK_NULL_POINTER("m1", m1, "../mtxuty-cvt.c", 55);
     LOG_UTILS_CHECK_NULL_POINTER("m2", m2, "../mtxuty-cvt.c", 56);
-    guMtxL2F(m1, m2);
+    guMtxL2F(m1->mf, m2);
 }
diff --git a/src/code/sys_matrix.c b/src/code/sys_matrix.c
index ce98460860..440e4c6d6c 100644
--- a/src/code/sys_matrix.c
+++ b/src/code/sys_matrix.c
@@ -1020,7 +1020,7 @@ void Matrix_SetTranslateUniformScaleMtx(Mtx* mtx, f32 scale, f32 translateX, f32
     MtxF mf;
 
     Matrix_SetTranslateUniformScaleMtxF(&mf, scale, translateX, translateY, translateZ);
-    guMtxF2L(&mf, mtx);
+    guMtxF2L(mf.mf, mtx);
 }
 
 void Matrix_SetTranslateUniformScaleMtx2(Mtx* mtx, f32 scale, f32 translateX, f32 translateY, f32 translateZ) {
diff --git a/src/libultra/gu/lookat.c b/src/libultra/gu/lookat.c
index 5313d3cc3e..e1c7500cf1 100644
--- a/src/libultra/gu/lookat.c
+++ b/src/libultra/gu/lookat.c
@@ -61,5 +61,5 @@ void guLookAt(Mtx* m, f32 xEye, f32 yEye, f32 zEye, f32 xAt, f32 yAt, f32 zAt, f
 
     guLookAtF(mf, xEye, yEye, zEye, xAt, yAt, zAt, xUp, yUp, zUp);
 
-    guMtxF2L((MtxF*)mf, m);
+    guMtxF2L(mf, m);
 }
diff --git a/src/libultra/gu/lookathil.c b/src/libultra/gu/lookathil.c
index d1070b579c..e9cf650a6e 100644
--- a/src/libultra/gu/lookathil.c
+++ b/src/libultra/gu/lookathil.c
@@ -157,5 +157,5 @@ void guLookAtHilite(Mtx* m, LookAt* l, Hilite* h, f32 xEye, f32 yEye, f32 zEye,
     guLookAtHiliteF(mf, l, h, xEye, yEye, zEye, xAt, yAt, zAt, xUp, yUp, zUp, xl1, yl1, zl1, xl2, yl2, zl2, hiliteWidth,
                     hiliteHeight);
 
-    guMtxF2L((MtxF*)mf, m);
+    guMtxF2L(mf, m);
 }
diff --git a/src/libultra/gu/mtxutil.c b/src/libultra/gu/mtxutil.c
index 8b13789179..e9e327f740 100644
--- a/src/libultra/gu/mtxutil.c
+++ b/src/libultra/gu/mtxutil.c
@@ -1 +1,63 @@
+#include "global.h"
 
+void guMtxF2L(f32 mf[4][4], Mtx* m) {
+    s32 i, j;
+    s32 e1, e2;
+    s32 *ai, *af;
+
+    ai = (s32*)&m->m[0][0];
+    af = (s32*)&m->m[2][0];
+
+    for (i = 0; i < 4; i++) {
+        for (j = 0; j < 2; j++) {
+            e1 = FTOFIX32(mf[i][j * 2]);
+            e2 = FTOFIX32(mf[i][j * 2 + 1]);
+            *(ai++) = (e1 & 0xFFFF0000) | ((e2 >> 16) & 0xFFFF);
+            *(af++) = ((e1 << 16) & 0xFFFF0000) | (e2 & 0xFFFF);
+        }
+    }
+}
+
+void guMtxL2F(f32 mf[4][4], Mtx* m) {
+    s32 i, j;
+    u32 e1, e2;
+    u32 *ai, *af;
+    s32 q1, q2;
+
+    ai = (u32*)&m->m[0][0];
+    af = (u32*)&m->m[2][0];
+
+    for (i = 0; i < 4; i++) {
+        for (j = 0; j < 2; j++) {
+            e1 = (*ai & 0xFFFF0000) | ((*af >> 16) & 0xFFFF);
+            e2 = ((*(ai++) << 16) & 0xFFFF0000) | (*(af++) & 0xFFFF);
+            q1 = *((s32*)&e1);
+            q2 = *((s32*)&e2);
+
+            mf[i][j * 2] = FIX32TOF(q1);
+            mf[i][j * 2 + 1] = FIX32TOF(q2);
+        }
+    }
+}
+
+void guMtxIdentF(f32 mf[4][4]) {
+    s32 i, j;
+
+    for (i = 0; i < 4; i++) {
+        for (j = 0; j < 4; j++) {
+            if (i == j) {
+                mf[i][j] = 1.0;
+            } else {
+                mf[i][j] = 0.0;
+            }
+        }
+    }
+}
+
+void guMtxIdent(Mtx* m) {
+    f32 mf[4][4];
+
+    guMtxIdentF(mf);
+
+    guMtxF2L(mf, m);
+}
diff --git a/src/libultra/gu/normalize.c b/src/libultra/gu/normalize.c
new file mode 100644
index 0000000000..6a0cac0200
--- /dev/null
+++ b/src/libultra/gu/normalize.c
@@ -0,0 +1,9 @@
+#include "global.h"
+
+void guNormalize(f32* x, f32* y, f32* z) {
+    f32 m = 1 / sqrtf(SQ(*x) + SQ(*y) + SQ(*z));
+
+    *x *= m;
+    *y *= m;
+    *z *= m;
+}
diff --git a/src/libultra/gu/ortho.c b/src/libultra/gu/ortho.c
index 517ba1dccc..62b6d79503 100644
--- a/src/libultra/gu/ortho.c
+++ b/src/libultra/gu/ortho.c
@@ -25,5 +25,5 @@ void guOrtho(Mtx* mtx, f32 left, f32 right, f32 bottom, f32 top, f32 near, f32 f
 
     guOrthoF(mf, left, right, bottom, top, near, far, scale);
 
-    guMtxF2L((MtxF*)mf, mtx);
+    guMtxF2L(mf, mtx);
 }
diff --git a/src/libultra/gu/perspective.c b/src/libultra/gu/perspective.c
index 21b0e1a0a6..3f700a814a 100644
--- a/src/libultra/gu/perspective.c
+++ b/src/libultra/gu/perspective.c
@@ -38,5 +38,6 @@ void guPerspective(Mtx* m, u16* perspNorm, f32 fovy, f32 aspect, f32 near, f32 f
     f32 mf[4][4];
 
     guPerspectiveF(mf, perspNorm, fovy, aspect, near, far, scale);
-    guMtxF2L((MtxF*)mf, m);
+
+    guMtxF2L(mf, m);
 }
diff --git a/src/libultra/gu/position.c b/src/libultra/gu/position.c
index 65517139d8..1b9a3525b2 100644
--- a/src/libultra/gu/position.c
+++ b/src/libultra/gu/position.c
@@ -50,5 +50,5 @@ void guPosition(Mtx* m, f32 rot, f32 pitch, f32 yaw, f32 scale, f32 x, f32 y, f3
 
     guPositionF(mf, rot, pitch, yaw, scale, x, y, z);
 
-    guMtxF2L((MtxF*)mf, m);
+    guMtxF2L(mf, m);
 }
diff --git a/src/libultra/gu/rotate.c b/src/libultra/gu/rotate.c
index 064006cdf4..b9108e1bc5 100644
--- a/src/libultra/gu/rotate.c
+++ b/src/libultra/gu/rotate.c
@@ -8,9 +8,11 @@ void guRotateF(f32 m[4][4], f32 a, f32 x, f32 y, f32 z) {
     f32 bc;
     f32 ca;
     f32 t;
+#if !PLATFORM_N64
     f32 xs;
     f32 ys;
     f32 zs;
+#endif
 
     guNormalize(&x, &y, &z);
 
@@ -25,9 +27,15 @@ void guRotateF(f32 m[4][4], f32 a, f32 x, f32 y, f32 z) {
 
     guMtxIdentF(m);
 
+#if PLATFORM_N64
+#define xs (x * sine)
+#define ys (y * sine)
+#define zs (z * sine)
+#else
     xs = x * sine;
     ys = y * sine;
     zs = z * sine;
+#endif
 
     t = x * x;
     m[0][0] = (1 - t) * cosine + t;
@@ -47,5 +55,6 @@ void guRotate(Mtx* m, f32 a, f32 x, f32 y, f32 z) {
     f32 mf[4][4];
 
     guRotateF(mf, a, x, y, z);
-    guMtxF2L((MtxF*)mf, m);
+
+    guMtxF2L(mf, m);
 }
diff --git a/src/libultra/gu/scale.c b/src/libultra/gu/scale.c
new file mode 100644
index 0000000000..525f2fb4c5
--- /dev/null
+++ b/src/libultra/gu/scale.c
@@ -0,0 +1,18 @@
+#include "global.h"
+
+void guScaleF(f32 m[4][4], f32 x, f32 y, f32 z) {
+    guMtxIdentF(m);
+
+    m[0][0] = x;
+    m[1][1] = y;
+    m[2][2] = z;
+    m[3][3] = 1;
+}
+
+void guScale(Mtx* m, f32 x, f32 y, f32 z) {
+    f32 mf[4][4];
+
+    guScaleF(mf, x, y, z);
+
+    guMtxF2L(mf, m);
+}
diff --git a/src/libultra/gu/translate.c b/src/libultra/gu/translate.c
new file mode 100644
index 0000000000..2753063d5d
--- /dev/null
+++ b/src/libultra/gu/translate.c
@@ -0,0 +1,17 @@
+#include "global.h"
+
+void guTranslateF(f32 m[4][4], f32 x, f32 y, f32 z) {
+    guMtxIdentF(m);
+
+    m[3][0] = x;
+    m[3][1] = y;
+    m[3][2] = z;
+}
+
+void guTranslate(Mtx* m, f32 x, f32 y, f32 z) {
+    f32 mf[4][4];
+
+    guTranslateF(mf, x, y, z);
+
+    guMtxF2L(mf, m);
+}
diff --git a/src/libultra/io/contsetch.c b/src/libultra/io/contsetch.c
index feab63cdb4..5ced5b6de4 100644
--- a/src/libultra/io/contsetch.c
+++ b/src/libultra/io/contsetch.c
@@ -7,6 +7,8 @@
  * direct SI devices.
  */
 s32 osContSetCh(u8 ch) {
+    s32 ret = 0;
+
     __osSiGetAccess();
 
     if (ch > MAXCONTROLLERS) {
@@ -17,5 +19,5 @@ s32 osContSetCh(u8 ch) {
 
     __osContLastCmd = CONT_CMD_END;
     __osSiRelAccess();
-    return 0;
+    return ret;
 }
diff --git a/src/libultra/io/epidma.c b/src/libultra/io/epidma.c
index 28565e72c0..ca57a9d170 100644
--- a/src/libultra/io/epidma.c
+++ b/src/libultra/io/epidma.c
@@ -2,7 +2,7 @@
 #include "ultra64/internal.h"
 
 s32 osEPiStartDma(OSPiHandle* handle, OSIoMesg* mb, s32 direction) {
-    s32 ret;
+    register s32 ret;
 
     if (!__osPiDevMgr.active) {
         return -1;
diff --git a/src/libultra/io/sptaskyielded.c b/src/libultra/io/sptaskyielded.c
index 4fec2a6d51..d04f673c54 100644
--- a/src/libultra/io/sptaskyielded.c
+++ b/src/libultra/io/sptaskyielded.c
@@ -1,8 +1,8 @@
 #include "global.h"
 
 u32 osSpTaskYielded(OSTask* task) {
-    u32 ret;
     u32 status = __osSpGetStatus();
+    u32 ret;
 
     if (status & SP_STATUS_YIELDED) {
         ret = OS_TASK_YIELDED;
diff --git a/src/libultra/libc/xldtob.c b/src/libultra/libc/xldtob.c
index 662561b4bf..a0ebe5d2d8 100644
--- a/src/libultra/libc/xldtob.c
+++ b/src/libultra/libc/xldtob.c
@@ -4,8 +4,8 @@
 
 #define BUFF_LEN 0x20
 
-short _Ldunscale(short*, _Pft*);
-void _Genld(_Pft*, char, char*, short, short);
+static short _Ldunscale(short*, _Pft*);
+static void _Genld(_Pft*, char, char*, short, short);
 
 static const double pows[] = { 10e0L, 10e1L, 10e3L, 10e7L, 10e15L, 10e31L, 10e63L, 10e127L, 10e255L };
 
@@ -156,7 +156,7 @@ void _Ldtob(_Pft* args, char code) {
     _Genld((_Pft*)args, code, ptr, nsig, exp);
 }
 
-short _Ldunscale(short* pex, _Pft* px) {
+static short _Ldunscale(short* pex, _Pft* px) {
     unsigned short* ps = (unsigned short*)px;
     short xchar = (ps[_D0] & _DMASK) >> _DOFF;
 
@@ -176,7 +176,7 @@ short _Ldunscale(short* pex, _Pft* px) {
     }
 }
 
-void _Genld(_Pft* px, char code, char* p, short nsig, short xexp) {
+static void _Genld(_Pft* px, char code, char* p, short nsig, short xexp) {
     const char point = '.';
 
     if (nsig <= 0) {
diff --git a/src/libultra/libc/xprintf.c b/src/libultra/libc/xprintf.c
index 9470e141fe..7fba40b4c4 100644
--- a/src/libultra/libc/xprintf.c
+++ b/src/libultra/libc/xprintf.c
@@ -40,7 +40,7 @@
 char spaces[] = "                                ";
 char zeroes[] = "00000000000000000000000000000000";
 
-void _Putfld(_Pft*, va_list*, char, char*);
+static void _Putfld(_Pft*, va_list*, char, char*);
 
 int _Printf(PrintCallback pfn, void* arg, const char* fmt, va_list ap) {
     _Pft x;
@@ -121,7 +121,7 @@ int _Printf(PrintCallback pfn, void* arg, const char* fmt, va_list ap) {
     }
 }
 
-void _Putfld(_Pft* px, va_list* pap, char code, char* ac) {
+static void _Putfld(_Pft* px, va_list* pap, char code, char* ac) {
     px->n0 = px->nz0 = px->n1 = px->nz1 = px->n2 = px->nz2 = 0;
 
     switch (code) {
diff --git a/src/libultra/os/exceptasm.s b/src/libultra/os/exceptasm.s
index 16ff4f5792..6b8003fd28 100644
--- a/src/libultra/os/exceptasm.s
+++ b/src/libultra/os/exceptasm.s
@@ -448,6 +448,13 @@ pi:
     andi    $t1, $s1, MI_INTR_PI
     beqz    $t1, dp
      nop
+#if PLATFORM_N64
+    // Clear interrupt and mask out pi interrupt
+    li      $t1, PI_STATUS_CLR_INTR
+    lui     $at, %hi(PHYS_TO_K1(PI_STATUS_REG))
+    andi    $s1, $s1, (MI_INTR_SP | MI_INTR_SI | MI_INTR_AI | MI_INTR_VI | MI_INTR_DP)
+    sw      $t1, %lo(PHYS_TO_K1(PI_STATUS_REG))($at)
+#else
     // Clear interrupt
     li      $t1, PI_STATUS_CLR_INTR
     lui     $at, %hi(PHYS_TO_K1(PI_STATUS_REG))
@@ -468,6 +475,7 @@ pi:
     // If the callback returns non-zero, don't post a pi event message
     bnez    $v0, skip_pi_mesg
      nop
+#endif
 no_pi_callback:
     // Post pi event message
     jal     send_mesg
@@ -847,10 +855,12 @@ LEAF(__osPopThread)
      sw     $t9, ($a0)
 END(__osPopThread)
 
+#if !PLATFORM_N64
 LEAF(__osNop)
     jr      $ra
      nop
 END(__osNop)
+#endif
 
 /**
  *  void __osDispatchThread(void);
diff --git a/src/libultra/os/getintmask.s b/src/libultra/os/getintmask.s
index e69de29bb2..2c6ddc86ed 100644
--- a/src/libultra/os/getintmask.s
+++ b/src/libultra/os/getintmask.s
@@ -0,0 +1,60 @@
+#include "ultra64/asm.h"
+#include "ultra64/R4300.h"
+#include "ultra64/rcp.h"
+#include "ultra64/exception.h"
+
+.set noat
+.set noreorder
+
+.section .text
+
+.balign 16
+
+/**
+ *  OSIntMask osGetIntMask(void);
+ *
+ *  Gets the interrupt enable mask for the current thread.
+ *  Interrupts that are not enabled in the global interrupt mask __OSGlobalIntMask
+ *   are not returned here. The global interrupt mask is OS-internal and is not
+ *   expected to change during runtime.
+ *
+ * @bug Some usage of the global interrupt mask is broken both in the
+ *       get/set interrupt mask routines and in the exception handler routines.
+ *       See the comment for osSetIntMask for more details.
+ */
+LEAF(osGetIntMask)
+    // Extract interrupt enable bits from current SR
+    mfc0    $v0, C0_SR
+    andi    $v0, $v0, (SR_IMASK | SR_IE)
+    // Get value of __OSGlobalIntMask
+    lui     $t0, %hi(__OSGlobalIntMask)
+    addiu   $t0, %lo(__OSGlobalIntMask)
+    lw      $t1, 0($t0)
+    // Bitwise-OR in the disabled CPU bits of __OSGlobalIntMask
+    li      $at, ~0
+    xor     $t0, $t1, $at
+    andi    $t0, $t0, SR_IMASK
+    or      $v0, $v0, $t0
+    // Fetch MI_INTR_MASK_REG
+    lui     $t1, %hi(PHYS_TO_K1(MI_INTR_MASK_REG))
+    lw      $t1, %lo(PHYS_TO_K1(MI_INTR_MASK_REG))($t1)
+    // If there are RCP interrupts masked
+    beqz    $t1, 1f
+    // Get value of __OSGlobalIntMask
+     lui    $t0, %hi(__OSGlobalIntMask)
+    addiu   $t0, %lo(__OSGlobalIntMask)
+    lw      $t0, 0($t0)
+    // Bitwise-OR in the disabled RCP bits of __OSGlobalIntMask
+    srl     $t0, $t0, RCP_IMASKSHIFT
+    li      $at, ~0
+    xor     $t0, $t0, $at
+    andi    $t0, $t0, (RCP_IMASK >> RCP_IMASKSHIFT)
+    or      $t1, $t1, $t0
+1:
+    // Shift the RCP bits to not conflict with the CPU bits
+    sll     $t2, $t1, RCP_IMASKSHIFT
+    // OR the CPU and RCP bits together
+    or      $v0, $v0, $t2
+    jr      $ra
+     nop
+END(osGetIntMask)
diff --git a/src/libultra/os/initialize.c b/src/libultra/os/initialize.c
index 0ee8698e7c..e985d551d9 100644
--- a/src/libultra/os/initialize.c
+++ b/src/libultra/os/initialize.c
@@ -16,7 +16,19 @@ OSHWIntr __OSGlobalIntMask = OS_IM_ALL;
 
 u32 __osFinalrom;
 
-void __createSpeedParam(void) {
+#if PLATFORM_N64
+
+#define OSINITIALIZE_FUNC osInitialize
+#define SPEED_PARAM_FUNC createSpeedParam
+
+static void SPEED_PARAM_FUNC(void);
+
+#else
+
+#define OSINITIALIZE_FUNC __osInitialize_common
+#define SPEED_PARAM_FUNC __createSpeedParam
+
+void SPEED_PARAM_FUNC(void) {
     __Dom1SpeedParam.type = DEVICE_TYPE_INIT;
     __Dom1SpeedParam.latency = IO_READ(PI_BSD_DOM1_LAT_REG);
     __Dom1SpeedParam.pulse = IO_READ(PI_BSD_DOM1_PWD_REG);
@@ -30,13 +42,20 @@ void __createSpeedParam(void) {
     __Dom2SpeedParam.relDuration = IO_READ(PI_BSD_DOM2_RLS_REG);
 }
 
-void __osInitialize_common(void) {
+#endif
+
+void OSINITIALIZE_FUNC(void) {
     u32 pifdata;
+#if PLATFORM_N64
+    u32 clock = 0;
+#endif
 
     __osFinalrom = true;
     __osSetSR(__osGetSR() | SR_CU1);
     __osSetFpcCsr(FPCSR_FS | FPCSR_EV);
+#if !PLATFORM_N64
     __osSetWatchLo(0x04900000);
+#endif
 
     while (__osSiRawReadIo((void*)(PIF_RAM_END - 3), &pifdata)) {
         ;
@@ -52,7 +71,7 @@ void __osInitialize_common(void) {
 
     osWritebackDCache((void*)K0BASE, E_VEC - K0BASE + sizeof(__osExceptionVector));
     osInvalICache((void*)K0BASE, E_VEC - K0BASE + sizeof(__osExceptionVector));
-    __createSpeedParam();
+    SPEED_PARAM_FUNC();
     osUnmapTLBAll();
     osMapTLBRdb();
 
@@ -82,5 +101,21 @@ void __osInitialize_common(void) {
     IO_WRITE(AI_BITRATE_REG, AI_MAX_BIT_RATE - 1);
 }
 
+#if PLATFORM_N64
+static void SPEED_PARAM_FUNC(void) {
+    __Dom1SpeedParam.type = DEVICE_TYPE_INIT;
+    __Dom1SpeedParam.latency = IO_READ(PI_BSD_DOM1_LAT_REG);
+    __Dom1SpeedParam.pulse = IO_READ(PI_BSD_DOM1_PWD_REG);
+    __Dom1SpeedParam.pageSize = IO_READ(PI_BSD_DOM1_PGS_REG);
+    __Dom1SpeedParam.relDuration = IO_READ(PI_BSD_DOM1_RLS_REG);
+
+    __Dom2SpeedParam.type = DEVICE_TYPE_INIT;
+    __Dom2SpeedParam.latency = IO_READ(PI_BSD_DOM2_LAT_REG);
+    __Dom2SpeedParam.pulse = IO_READ(PI_BSD_DOM2_PWD_REG);
+    __Dom2SpeedParam.pageSize = IO_READ(PI_BSD_DOM2_PGS_REG);
+    __Dom2SpeedParam.relDuration = IO_READ(PI_BSD_DOM2_RLS_REG);
+}
+#else
 void __osInitialize_autodetect(void) {
 }
+#endif
diff --git a/src/libultra/os/setintmask.s b/src/libultra/os/setintmask.s
index 3d2bc5b9c9..e48c1b376f 100644
--- a/src/libultra/os/setintmask.s
+++ b/src/libultra/os/setintmask.s
@@ -99,8 +99,8 @@ ENDDATA(__osRcpImTable)
  *  The returned value is the previous interrupt enable mask so that it can be
  *   restored later.
  *
- * @bug Some usage of the global interrupt mask is broken both in here and in the
- *       exception handler routines.
+ * @bug Some usage of the global interrupt mask is broken both in the
+ *       get/set interrupt mask routines and in the exception handler routines.
  *      While a thread is running, the C0_SR interrupt enable bits contain the
  *       interrupt enable bits for the current thread masked by the global
  *       interrupt mask. There is an attempt to recover only the original interrupt
diff --git a/src/libultra/os/settime.c b/src/libultra/os/settime.c
index 8b13789179..2be47ed9ed 100644
--- a/src/libultra/os/settime.c
+++ b/src/libultra/os/settime.c
@@ -1 +1,5 @@
+#include "global.h"
 
+void osSetTime(OSTime time) {
+    __osCurrentTime = time;
+}
diff --git a/src/libultra/os/settimer.c b/src/libultra/os/settimer.c
index 7775b987bf..40e1ba83be 100644
--- a/src/libultra/os/settimer.c
+++ b/src/libultra/os/settimer.c
@@ -1,11 +1,13 @@
 #include "global.h"
 
 s32 osSetTimer(OSTimer* timer, OSTime countdown, OSTime interval, OSMesgQueue* mq, OSMesg msg) {
-    UNUSED OSTime time;
+    OSTime time;
+#if !PLATFORM_N64
     OSTimer* next;
     u32 count;
     u32 value;
     u32 prevInt;
+#endif
 
     timer->next = NULL;
     timer->prev = NULL;
@@ -19,6 +21,12 @@ s32 osSetTimer(OSTimer* timer, OSTime countdown, OSTime interval, OSMesgQueue* m
     timer->mq = mq;
     timer->msg = msg;
 
+#if PLATFORM_N64
+    time = __osInsertTimer(timer);
+    if (__osTimerList->next == timer) {
+        __osSetTimerIntr(time);
+    }
+#else
     prevInt = __osDisableInt();
     if (__osTimerList->next != __osTimerList) {
         if (1) {}
@@ -38,6 +46,7 @@ s32 osSetTimer(OSTimer* timer, OSTime countdown, OSTime interval, OSMesgQueue* m
     __osSetTimerIntr(__osTimerList->next->value);
 
     __osRestoreInt(prevInt);
+#endif
 
     return 0;
 }
diff --git a/src/libultra/os/timerintr.c b/src/libultra/os/timerintr.c
index 7e2e361388..943aca0ffc 100644
--- a/src/libultra/os/timerintr.c
+++ b/src/libultra/os/timerintr.c
@@ -63,9 +63,11 @@ void __osSetTimerIntr(OSTime time) {
     OSTime newTime;
     u32 prevInt;
 
+#if !PLATFORM_N64
     if (time < 468) {
         time = 468;
     }
+#endif
 
     prevInt = __osDisableInt();
 
diff --git a/tools/check_disasm_metadata_unksyms.py b/tools/check_disasm_metadata_unksyms.py
index c133c41e03..5624ea962c 100755
--- a/tools/check_disasm_metadata_unksyms.py
+++ b/tools/check_disasm_metadata_unksyms.py
@@ -19,6 +19,7 @@ AudioDebug_ProcessInput
 func_800FF334
 n64dd_SetDiskVersion
 sJpegTask  _n64ddSegmentRomStart  _n64ddSegmentRomEnd  _n64ddSegmentStart  _string_n64dd_c
+_Putfld  _Ldunscale  _Genld
 """.split()
 
 
diff --git a/tools/disasm/ntsc-1.2/files_code.csv b/tools/disasm/ntsc-1.2/files_code.csv
index 65c2757db9..553114dc89 100644
--- a/tools/disasm/ntsc-1.2/files_code.csv
+++ b/tools/disasm/ntsc-1.2/files_code.csv
@@ -138,7 +138,7 @@ BD970,800CF050,src/code/printutils
 BD9D0,800CF0B0,src/code/jpegutils
 BDEE0,800CF5C0,src/code/jpegdecoder
 BE4D0,800CFBB0,src/libultra/os/getintmask
-BE530,800CFC10,src/libultra/mgu/scale
+BE530,800CFC10,src/libultra/gu/scale
 BE5D0,800CFCB0,src/libultra/gu/sinf
 BE790,800CFE70,src/libultra/gu/sins
 BE800,800CFEE0,src/libultra/io/sptask
@@ -165,7 +165,7 @@ C17A0,800D2E80,src/libultra/io/sptaskyielded
 C1820,800D2F00,src/libultra/gu/rotate
 C1A10,800D30F0,src/libultra/io/aisetfreq
 C1B60,800D3240,src/libultra/os/getactivequeue
-C1B70,800D3250,src/libultra/mgu/normalize
+C1B70,800D3250,src/libultra/gu/normalize
 C1C00,800D32E0,src/libultra/io/dpgetstat
 C1C10,800D32F0,src/libultra/io/dpsetstat
 C1C20,800D3300,src/libultra/gu/ortho
@@ -177,7 +177,7 @@ C2020,800D3700,src/libultra/gu/us2dex
 C21A0,800D3880,src/libultra/io/pfsselectbank
 C2220,800D3900,src/libultra/io/contsetch
 C2290,800D3970,src/libultra/io/aigetlen
-C22A0,800D3980,src/libultra/mgu/translate
+C22A0,800D3980,src/libultra/gu/translate
 C2340,800D3A20,src/libultra/io/contramwrite
 C2590,800D3C70,src/libultra/io/pfsgetstatus
 C27C0,800D3EA0,src/libultra/io/contpfs
diff --git a/undefined_syms.txt b/undefined_syms.txt
index ef44a7fb87..0cfc7eac26 100644
--- a/undefined_syms.txt
+++ b/undefined_syms.txt
@@ -14,7 +14,6 @@ D_06000000 = 0x06000000;
 
 // boot_main.c
 func_80001720 = 0x80001720;
-osInitialize = 0x80003230;
 
 // cic6105.c
 cic6105ucodeTextStart = 0x80006720;
@@ -22,8 +21,8 @@ func_800AE258_unknown = 0x800AE258;
 func_800AE1E0_unknown = 0x800AE1E0;
 
 // code_n64dd_800AD410.c
-osGetIntMask = 0x800CFBB0;
-osSetTime = 0x800D3660;
+func_800ADCD8_unknown = 0x800ADCD8;
+func_800AE170_unknown = 0x800AE170;
 func_801C7740_unknown = 0x801C7740;
 func_801C8510_unknown = 0x801C8510;
 D_801DA410 = 0x801DA410;