diff --git a/Makefile b/Makefile
index 8b9d461d28..9741d456ce 100644
--- a/Makefile
+++ b/Makefile
@@ -207,6 +207,8 @@ $(shell mkdir -p build/baserom $(foreach dir,$(SRC_DIRS) $(ASM_DIRS) $(ASSET_BIN
 # directory flags
 build/src/boot/O2/%.o: OPTFLAGS := -O2
 
+build/src/boot/libc/%.o: OPTFLAGS := -O2
+build/src/boot/libm/%.o: OPTFLAGS := -O2
 build/src/boot/libc64/%.o: OPTFLAGS := -O2
 
 build/src/libultra/os/%.o: OPTFLAGS := -O1
diff --git a/include/PR/ultratypes.h b/include/PR/ultratypes.h
index 3f04c6ed3c..0e48d50dce 100644
--- a/include/PR/ultratypes.h
+++ b/include/PR/ultratypes.h
@@ -22,11 +22,14 @@ typedef volatile s64 vs64;
 typedef float  f32;
 typedef double f64;
 
+#if !defined(_SIZE_T)
+#define _SIZE_T
 #if defined(_MIPS_SZLONG) && (_MIPS_SZLONG == 64)
 typedef unsigned long size_t;
 #else
 typedef unsigned int  size_t;
 #endif
+#endif
 
 #ifndef NULL
 #define NULL ((void*)0)
diff --git a/include/functions.h b/include/functions.h
index d83f61a359..53f6af07f6 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -65,12 +65,6 @@ void MtxConv_L2F(MtxF* mtx, Mtx* mf);
 
 s32 func_80086620(OSMesgQueue* param_1, PadMgr* param_2, OSContStatus* param_3);
 
-f32 fmodf(f32 dividend, f32 divisor);
-void* __osMemset(void* ptr, s32 val, size_t size);
-s32 __osStrcmp(const char* str1, const char* str2);
-char* __osStrcpy(char* dst, const char* src);
-void* __osMemcpy(void* dst, void* src, size_t size);
-
 // void EnItem00_SetObject(EnItem00* this, PlayState* play, f32* shadowOffset, f32* shadowScale);
 // void EnItem00_Init(Actor* thisx, PlayState* play);
 // void EnItem00_Destroy(Actor* thisx, PlayState* play);
diff --git a/include/libc/math.h b/include/libc/math.h
index 6e904dca83..25d9e5a937 100644
--- a/include/libc/math.h
+++ b/include/libc/math.h
@@ -17,4 +17,6 @@ float fabsf(float f);
 double sqrt(double d);
 #pragma intrinsic(sqrt)
 
+float fmodf(float dividend, float divisor);
+
 #endif
diff --git a/include/libc/stddef.h b/include/libc/stddef.h
index d753396146..3b4ed699c1 100644
--- a/include/libc/stddef.h
+++ b/include/libc/stddef.h
@@ -1,9 +1,16 @@
 #ifndef LIBC_STDDEF_H
 #define LIBC_STDDEF_H
 
-#include "PR/ultratypes.h"
+#if !defined(_SIZE_T)
+#define _SIZE_T
+#if defined(_MIPS_SZLONG) && (_MIPS_SZLONG == 64)
+typedef unsigned long size_t;
+#else
+typedef unsigned int  size_t;
+#endif
+#endif
 
-typedef s32 ptrdiff_t;
+typedef signed long ptrdiff_t;
 
 #ifdef __GNUC__
 #define offsetof(structure, member) __builtin_offsetof (structure, member)
diff --git a/include/libc/string.h b/include/libc/string.h
index 9c6a1cb087..4fb99e71ee 100644
--- a/include/libc/string.h
+++ b/include/libc/string.h
@@ -3,10 +3,13 @@
 
 #include "libc/stddef.h"
 
-
 const char* strchr(const char* s, int c);
 size_t strlen(const char* s);
 void* memcpy(void* s1, const void* s2, size_t n);
 
+void* memset(void* ptr, int val, size_t size);
+int strcmp(const char* str1, const char* str2);
+char* strcpy(char* dst, const char* src);
+void* memmove(void* dst, const void* src, size_t size);
 
 #endif
diff --git a/spec b/spec
index dbe71ed3bf..fc733befb9 100644
--- a/spec
+++ b/spec
@@ -237,11 +237,11 @@ beginseg
     include "build/src/libultra/os/sethwinterrupt.o"
     include "build/asm/boot/getwatchlo.text.o"
     include "build/asm/boot/setwatchlo.text.o"
-    include "build/src/boot/O2/fmodf.o"
-    include "build/src/boot/O2/__osMemset.o"
-    include "build/src/boot/O2/__osStrcmp.o"
-    include "build/src/boot/O2/__osStrcpy.o"
-    include "build/src/boot/O2/__osMemcpy.o"
+    include "build/src/boot/libm/fmodf.o"
+    include "build/src/boot/libc/memset.o"
+    include "build/src/boot/libc/strcmp.o"
+    include "build/src/boot/libc/strcpy.o"
+    include "build/src/boot/libc/memmove.o"
     include "build/src/boot/build.o"
 endseg
 
diff --git a/src/boot/O2/__osMemset.c b/src/boot/O2/__osMemset.c
deleted file mode 100644
index 0c4172e9fa..0000000000
--- a/src/boot/O2/__osMemset.c
+++ /dev/null
@@ -1,11 +0,0 @@
-#include "global.h"
-
-void* __osMemset(void* ptr, s32 val, size_t size) {
-    u8* dst = ptr;
-    register s32 rem;
-
-    for (rem = size--; rem != 0; rem = size--) {
-        *dst++ = val;
-    }
-    return ptr;
-}
diff --git a/src/boot/O2/__osMemcpy.c b/src/boot/libc/memmove.c
similarity index 66%
rename from src/boot/O2/__osMemcpy.c
rename to src/boot/libc/memmove.c
index 2e25b23f08..720de0facf 100644
--- a/src/boot/O2/__osMemcpy.c
+++ b/src/boot/libc/memmove.c
@@ -1,9 +1,9 @@
-#include "global.h"
+#include "libc/string.h"
 
-void* __osMemcpy(void* dst, void* src, size_t size) {
-    u8* _dst = dst;
-    u8* _src = src;
-    register s32 rem;
+void* memmove(void* dst, const void* src, size_t size) {
+    unsigned char* _dst = dst;
+    const unsigned char* _src = src;
+    register size_t rem;
 
     if (_dst == _src) {
         return dst;
diff --git a/src/boot/libc/memset.c b/src/boot/libc/memset.c
new file mode 100644
index 0000000000..7e0b1c0ed1
--- /dev/null
+++ b/src/boot/libc/memset.c
@@ -0,0 +1,12 @@
+#include "libc/string.h"
+
+void* memset(void* ptr, int val, size_t size) {
+    unsigned char* dst = ptr;
+    register size_t rem;
+
+    for (rem = size--; rem != 0; rem = size--) {
+        *dst++ = val;
+    }
+
+    return ptr;
+}
diff --git a/src/boot/O2/__osStrcmp.c b/src/boot/libc/strcmp.c
similarity index 56%
rename from src/boot/O2/__osStrcmp.c
rename to src/boot/libc/strcmp.c
index 10bd2fa92b..d65e4411f7 100644
--- a/src/boot/O2/__osStrcmp.c
+++ b/src/boot/libc/strcmp.c
@@ -1,12 +1,13 @@
-#include "global.h"
+#include "libc/string.h"
 
-s32 __osStrcmp(const char* str1, const char* str2) {
-    char c1;
-    char c2;
+int strcmp(const char* str1, const char* str2) {
+    unsigned char c1;
+    unsigned char c2;
 
     do {
         c1 = *str1++;
         c2 = *str2++;
+
         if (c1 != c2) {
             return c1 - c2;
         }
diff --git a/src/boot/O2/__osStrcpy.c b/src/boot/libc/strcpy.c
similarity index 63%
rename from src/boot/O2/__osStrcpy.c
rename to src/boot/libc/strcpy.c
index 86a98a804a..8166a47e0e 100644
--- a/src/boot/O2/__osStrcpy.c
+++ b/src/boot/libc/strcpy.c
@@ -1,6 +1,6 @@
-#include "global.h"
+#include "libc/string.h"
 
-char* __osStrcpy(char* dst, const char* src) {
+char* strcpy(char* dst, const char* src) {
     char* _dst = dst;
 
     while (*src != '\0') {
diff --git a/src/boot/libc64/__osMalloc.c b/src/boot/libc64/__osMalloc.c
index 2c736740bf..5540089975 100644
--- a/src/boot/libc64/__osMalloc.c
+++ b/src/boot/libc64/__osMalloc.c
@@ -1,10 +1,10 @@
 #include "libc64/os_malloc.h"
 
 #include "alignment.h"
-#include "functions.h" // for __osMemcpy
 #include "libc/stdbool.h"
 #include "libc/stdint.h"
-#include "macros.h" // for ARRAY_COUNT
+#include "libc/string.h"
+#include "macros.h"
 
 #define FILL_ALLOCBLOCK (1 << 0)
 #define FILL_FREEBLOCK (1 << 1)
@@ -374,7 +374,7 @@ void* __osRealloc(Arena* arena, void* ptr, size_t newSize) {
                 next2 = (void*)((uintptr_t)next + diff);
                 node->next = next2;
                 node->size = newSize;
-                __osMemcpy(next2, next, sizeof(ArenaNode));
+                memmove(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);
diff --git a/src/boot/O2/fmodf.c b/src/boot/libm/fmodf.c
similarity index 61%
rename from src/boot/O2/fmodf.c
rename to src/boot/libm/fmodf.c
index 2f8aa74bfb..0c2df736dd 100644
--- a/src/boot/O2/fmodf.c
+++ b/src/boot/libm/fmodf.c
@@ -1,7 +1,7 @@
-#include "global.h"
+#include "libc/math.h"
 
-f32 fmodf(f32 dividend, f32 divisor) {
-    s32 quotient;
+float fmodf(float dividend, float divisor) {
+    int quotient;
 
     if (divisor == 0.0f) {
         return 0.0f;
diff --git a/src/code/cutscene_camera.c b/src/code/cutscene_camera.c
index d5f3ef4a3b..53474bf889 100644
--- a/src/code/cutscene_camera.c
+++ b/src/code/cutscene_camera.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "libc/string.h"
 
 static CutsceneCamera* sCurCsCamera;
 
@@ -44,8 +45,8 @@ s32 CutsceneCamera_Init(Camera* camera, CutsceneCamera* csCamera) {
 
     sCurCsCamera = csCamera;
 
-    __osMemset(&csCamera->eyeInterp, 0, sizeof(CutsceneCameraInterp));
-    __osMemset(&csCamera->atInterp, 0, sizeof(CutsceneCameraInterp));
+    memset(&csCamera->eyeInterp, 0, sizeof(CutsceneCameraInterp));
+    memset(&csCamera->atInterp, 0, sizeof(CutsceneCameraInterp));
 
     csCamera->eyeInterp.type = csCamera->atInterp.type = CS_CAM_INTERP_OFF;
 
diff --git a/src/code/z_camera.c b/src/code/z_camera.c
index 0bfcafed06..5b58e939a8 100644
--- a/src/code/z_camera.c
+++ b/src/code/z_camera.c
@@ -6955,7 +6955,7 @@ void Camera_Init(Camera* camera, View* view, CollisionContext* colCtx, PlayState
     s16 curUID;
     s16 j;
 
-    __osMemset(camera, 0, sizeof(Camera));
+    memset(camera, 0, sizeof(Camera));
 
     camera->play = sCamPlayState = play;
     curUID = sCameraNextUID;
diff --git a/src/code/z_kankyo.c b/src/code/z_kankyo.c
index 98fdc84fb6..506d7d3589 100644
--- a/src/code/z_kankyo.c
+++ b/src/code/z_kankyo.c
@@ -65,6 +65,7 @@ Gfx* sSkyboxStarsDList;
 #include "objects/gameplay_keep/gameplay_keep.h"
 #include "objects/gameplay_field_keep/gameplay_field_keep.h"
 #include "overlays/kaleido_scope/ovl_kaleido_scope/z_kaleido_scope.h"
+#include "libc/string.h"
 
 // Data
 f32 sSandstormLerpScale = 0.0f;
@@ -1298,7 +1299,7 @@ void Environment_UpdateLights(PlayState* play, EnvironmentContext* envCtx, Light
     AdjLightSettings spA4[4];
 
     var_fs3 = 0.0f;
-    __osMemset(spA4, 0, sizeof(AdjLightSettings) * ARRAY_COUNT(spA4));
+    memset(spA4, 0, sizeof(AdjLightSettings) * ARRAY_COUNT(spA4));
     lightSettingsList = play->envCtx.lightSettingsList;
 
     if ((envCtx->lightSettingOverride != LIGHT_SETTING_OVERRIDE_NONE) &&
diff --git a/src/code/z_quake.c b/src/code/z_quake.c
index 19db37c63c..9423983e1c 100644
--- a/src/code/z_quake.c
+++ b/src/code/z_quake.c
@@ -1,5 +1,6 @@
 #include "prevent_bss_reordering.h"
 #include "global.h"
+#include "libc/string.h"
 #include "z64quake.h"
 #include "z64view.h"
 
@@ -174,7 +175,7 @@ QuakeRequest* Quake_RequestImpl(Camera* camera, u32 type) {
     s16 index = Quake_GetFreeIndex();
     QuakeRequest* req = &sQuakeRequests[index];
 
-    __osMemset(req, 0, sizeof(QuakeRequest));
+    memset(req, 0, sizeof(QuakeRequest));
 
     req->camera = camera;
     req->camId = camera->camId;
diff --git a/src/libultra/voice/voicecrc.c b/src/libultra/voice/voicecrc.c
index 36ffc4373a..58e405fbdb 100644
--- a/src/libultra/voice/voicecrc.c
+++ b/src/libultra/voice/voicecrc.c
@@ -4,6 +4,8 @@
  *
  * For general information about CRC, see the crc.c file (that's a lot of c's!).
  */
+
+#include "ultra64.h"
 #include "libc/stddef.h"
 
 #define VOICE_CRC_LENGTH 8
diff --git a/tools/disasm/files.txt b/tools/disasm/files.txt
index a4fbcd21be..5ceabe10f3 100644
--- a/tools/disasm/files.txt
+++ b/tools/disasm/files.txt
@@ -239,10 +239,10 @@
             0x80096810 : "getwatchlo",
             0x80096820 : "setwatchlo",
             0x80096830 : "fmodf",
-            0x80096880 : "__osMemset",
-            0x800968B0 : "__osStrcmp",
-            0x800968F0 : "__osStrcpy",
-            0x80096930 : "__osMemcpy",
+            0x80096880 : "memset",
+            0x800968B0 : "strcmp",
+            0x800968F0 : "strcpy",
+            0x80096930 : "memmove",
 
             # .data section
             0x800969C0 : "rspboot",
diff --git a/tools/disasm/functions.txt b/tools/disasm/functions.txt
index d956be2d4d..11341ea5bd 100644
--- a/tools/disasm/functions.txt
+++ b/tools/disasm/functions.txt
@@ -480,10 +480,10 @@
     0x80096810:("__osGetWatchLo",),
     0x80096820:("__osSetWatchLo",),
     0x80096830:("fmodf",),
-    0x80096880:("__osMemset",),
-    0x800968B0:("__osStrcmp",),
-    0x800968F0:("__osStrcpy",),
-    0x80096930:("__osMemcpy",),
+    0x80096880:("memset",),
+    0x800968B0:("strcmp",),
+    0x800968F0:("strcpy",),
+    0x80096930:("memmove",),
     0x800A5AC0:("EnAObj_Init",),
     0x800A5B6C:("EnAObj_Destroy",),
     0x800A5B98:("EnAObj_Idle",),
diff --git a/tools/sizes/boot_functions.csv b/tools/sizes/boot_functions.csv
index ef0ac1e974..2f01be07b3 100644
--- a/tools/sizes/boot_functions.csv
+++ b/tools/sizes/boot_functions.csv
@@ -477,7 +477,7 @@ asm/non_matchings/boot/sethwinterrupt/__osSetHWIntrRoutine.s,__osSetHWIntrRoutin
 asm/non_matchings/boot/getwatchlo/__osGetWatchLo.s,__osGetWatchLo,0x80096810,0x4
 asm/non_matchings/boot/setwatchlo/__osSetWatchLo.s,__osSetWatchLo,0x80096820,0x4
 asm/non_matchings/boot/fmodf/fmodf.s,fmodf,0x80096830,0x14
-asm/non_matchings/boot/__osMemset/__osMemset.s,__osMemset,0x80096880,0xC
-asm/non_matchings/boot/__osStrcmp/__osStrcmp.s,__osStrcmp,0x800968B0,0x10
-asm/non_matchings/boot/__osStrcpy/__osStrcpy.s,__osStrcpy,0x800968F0,0x10
-asm/non_matchings/boot/__osMemcpy/__osMemcpy.s,__osMemcpy,0x80096930,0x24
+asm/non_matchings/boot/memset/memset.s,memset,0x80096880,0xC
+asm/non_matchings/boot/strcmp/strcmp.s,strcmp,0x800968B0,0x10
+asm/non_matchings/boot/strcpy/strcpy.s,strcpy,0x800968F0,0x10
+asm/non_matchings/boot/memmove/memmove.s,memmove,0x80096930,0x24