diff --git a/include/lib/math.h b/include/lib/math.h
index 91e49409..a11f5583 100644
--- a/include/lib/math.h
+++ b/include/lib/math.h
@@ -11,13 +11,13 @@ typedef s16 q4;
 #define INT_TO_Q20(n) ((s32)((n) << 12))
 #define FLOAT_TO_Q20(n) ((s32)(((n) * 8192 + 1) / 2))
 #define ROUND_Q20(n) (((s32)(n) + 0x800) >> 12)
-#define MUL_Q20(a,b) ROUND_Q20((a) * (b))
+#define MUL_Q20(a,b) (q20)((((s64)(a)) * ((s64)(b)) + 0x800) >> 12)
 
 #define DEG_TO_ANG(n) ((n) * 0x10000 / 360)
 #define SIN(n) (gSinCosTable[2 * ((n) >> 4)])
 #define COS(n) (gSinCosTable[2 * ((n) >> 4) + 1])
 
-extern "C" s16 Atan2(s32 x, s32 y);
+extern "C" s32 Atan2(s32 x, s32 y);
 extern q4 gSinCosTable[];
 
 typedef struct {
@@ -49,17 +49,20 @@ extern "C" q20 Vec3p_Length(Vec3p *a);
 extern "C" void Vec3p_Normalize(Vec3p *vec, Vec3p *out);
 extern "C" void Vec3p_Axpy(q20 a, Vec3p *x, Vec3p *y, Vec3p *out);
 extern "C" q20 Vec3p_Distance(Vec3p *a, Vec3p *b);
-inline void Vec3p_Rotate(Vec3p *vec, s16 angle, Vec3p *out) {
-    q20 sin = SIN(angle);
-    q20 zSin = MUL_Q20(vec->z, sin);
-    out->x += zSin;
-    q20 cos = COS(angle);
-    q20 zCos = MUL_Q20(vec->z, cos);
-    out->z += zCos;
-    q20 xCos = MUL_Q20(vec->x, cos);
-    out->x += xCos;
-    q20 xSin = MUL_Q20(vec->x, -sin);
-    out->z += xSin;
+
+inline void Vec3p_Rotate(Vec3p *vec, q20 sin, q20 cos, Vec3p *out) {
+    out->x += MUL_Q20(vec->z, sin);
+    out->z += MUL_Q20(vec->z, cos);
+    out->x += MUL_Q20(vec->x, cos);
+    out->z += MUL_Q20(vec->x, -sin);
+}
+
+inline void Vec3p_CopyXZ(Vec3p *vec, Vec3p *out) {
+    q20 z = vec->z;
+    q20 x = vec->x;
+    out->x = x;
+    out->y = 0;
+    out->z = z;
 }
 
 typedef struct {
diff --git a/include/types.h b/include/types.h
index baa3fb32..a0952eff 100644
--- a/include/types.h
+++ b/include/types.h
@@ -1,10 +1,12 @@
 #ifndef PH_TYPES_H
 #define PH_TYPES_H
 
+typedef unsigned long long u64;
 typedef unsigned int u32;
 typedef unsigned short u16;
 typedef unsigned char u8;
 
+typedef long long s64;
 typedef int s32;
 typedef short s16;
 typedef char s8;