diff --git a/Makefile.mak b/Makefile.mak
index e195e139..c4df29d6 100644
--- a/Makefile.mak
+++ b/Makefile.mak
@@ -152,17 +152,17 @@ bin\th05\res_kso.com: th05\res_kso.cpp
 $**
 | masters.lib
 
-bin\th05\op.exe: th05\op010.cpp bin\th05\op.obj th05\op011.cpp th05\m_char.cpp bin\th05\musicp_c.obj bin\th05\musicp_a.obj bin\th05\bgimager.obj bin\th05\snd_load.obj bin\th05\snd_kaja.obj bin\th05\pi_cpp_1.obj bin\th05\pi_asm_1.obj bin\th05\pi_cpp_2.obj bin\th05\pi_asm_2.obj bin\th05\initop.obj bin\th05\input_s.obj bin\th05\inp_h_w.obj bin\th05\snd_dlym.obj th05\cdg_p_nc.cpp bin\th05\frmdelay.obj bin\th04\cdg_load.obj bin\th05\egcrect.obj bin\hfliplut.obj
+bin\th05\op.exe: th05\op010.cpp bin\th05\op.obj th05\op011.cpp th05\m_char.cpp bin\th05\vector.obj bin\th05\musicp_c.obj bin\th05\musicp_a.obj bin\th05\bgimager.obj bin\th05\snd_load.obj bin\th05\snd_kaja.obj bin\th05\pi_cpp_1.obj bin\th05\pi_asm_1.obj bin\th05\pi_cpp_2.obj bin\th05\pi_asm_2.obj bin\th05\initop.obj bin\th05\input_s.obj bin\th05\inp_h_w.obj bin\th05\snd_dlym.obj th05\cdg_p_nc.cpp bin\th05\frmdelay.obj bin\th04\cdg_load.obj bin\th05\egcrect.obj bin\hfliplut.obj
 	$(CC) $(CFLAGS) $(LARGE_LFLAGS) -DGAME=5 -DBINARY='O' -3 -Z -nbin\th05\ -eOP.EXE @&&|
 $**
 |
 
-bin\th05\main.exe: bin\th05\main.obj th05\main010.cpp th05\main011.cpp th05\p_common.cpp th05\p_reimu.cpp th05\p_marisa.cpp th05\p_mima.cpp th05\p_yuuka.cpp bin\th05\player.obj bin\th05\hud_bar.obj bin\th05\scoreupd.obj th05\main012.cpp th05\main013.cpp bin\hfliplut.obj bin\th05\bullet.obj bin\th05\snd_load.obj bin\th05\snd_kaja.obj bin\th05\initmain.obj bin\th05\input_s.obj bin\th05\inp_h_w.obj bin\th05\frmdelay.obj bin\th04\cdg_load.obj th05\main031.cpp th05\main032.cpp th05\main033.cpp th05\main034.cpp
+bin\th05\main.exe: bin\th05\main.obj th05\main010.cpp th05\main011.cpp th05\p_common.cpp th05\p_reimu.cpp th05\p_marisa.cpp th05\p_mima.cpp th05\p_yuuka.cpp bin\th05\player.obj bin\th05\hud_bar.obj bin\th05\scoreupd.obj th05\main012.cpp th05\main013.cpp bin\hfliplut.obj bin\th05\bullet.obj bin\th05\vector.obj bin\th05\snd_load.obj bin\th05\snd_kaja.obj bin\th05\initmain.obj bin\th05\input_s.obj bin\th05\inp_h_w.obj bin\th05\frmdelay.obj bin\th04\cdg_load.obj th05\main031.cpp th05\main032.cpp th05\main033.cpp th05\main034.cpp
 	$(CC) $(CFLAGS) $(LARGE_LFLAGS) -3 -Z -DGAME=5 -DBINARY='M' -nbin\th05\ -eMAIN.EXE @&&|
 $**
 |
 
-bin\th05\maine.exe: bin\th05\maine.obj th05\maine011.cpp th05\regist.cpp th05\staff.cpp bin\th05\bgimager.obj bin\th05\snd_load.obj bin\th05\snd_kaja.obj bin\th05\pi_cpp_1.obj bin\th05\pi_asm_1.obj bin\th05\pi_cpp_2.obj bin\th05\pi_asm_2.obj bin\th05\initmain.obj bin\th05\input_s.obj bin\th05\inp_h_w.obj bin\th05\snd_dlym.obj bin\th05\frmdelay.obj bin\th04\cdg_load.obj bin\th05\egcrect.obj bin\hfliplut.obj
+bin\th05\maine.exe: bin\th05\maine.obj th05\maine011.cpp th05\regist.cpp th05\staff.cpp bin\th05\vector.obj bin\th05\bgimager.obj bin\th05\snd_load.obj bin\th05\snd_kaja.obj bin\th05\pi_cpp_1.obj bin\th05\pi_asm_1.obj bin\th05\pi_cpp_2.obj bin\th05\pi_asm_2.obj bin\th05\initmain.obj bin\th05\input_s.obj bin\th05\inp_h_w.obj bin\th05\snd_dlym.obj bin\th05\frmdelay.obj bin\th04\cdg_load.obj bin\th05\egcrect.obj bin\hfliplut.obj
 	$(CC) $(CFLAGS) $(LARGE_LFLAGS) -DGAME=5 -DBINARY='E' -Z -nbin\th05\ -eMAINE.EXE @&&|
 $**
 |
diff --git a/th04/math/vector.cpp b/th04/math/vector.cpp
new file mode 100644
index 00000000..a7d65c1e
--- /dev/null
+++ b/th04/math/vector.cpp
@@ -0,0 +1,54 @@
+#pragma codeseg SHARED_
+#pragma option -3
+
+extern "C" {
+#include <stddef.h>
+#include "platform.h"
+#include "pc98.h"
+#include "master.hpp"
+#include "th01/math/subpixel.hpp"
+#include "th01/math/vector.hpp"
+#include "th04/math/vector.hpp"
+
+#define polar_by_offset(radius, table, offset) ( \
+	static_cast<long>(radius) * *reinterpret_cast<const short *>( \
+		reinterpret_cast<const int8_t*>(table) + offset \
+	))
+
+static inline pixel_t polar_x_fast_unsafe(
+	pixel_t center, pixel_t &radius, size_t table_offset
+) {
+	return ((polar_by_offset(radius, CosTable8, table_offset) >> 8) + center);
+}
+
+static inline pixel_t polar_y_fast_unsafe(
+	pixel_t center, pixel_t &radius, size_t table_offset
+) {
+	return ((polar_by_offset(radius, SinTable8, table_offset) >> 8) + center);
+}
+
+#undef polar_by_offset
+
+int pascal vector1_at(int origin, int length, int angle)
+{
+	return (((static_cast<long>(length) * angle) >> 8) + origin);
+}
+
+void pascal vector2_at(
+	SPPoint near &ret,
+	subpixel_t origin_x,
+	subpixel_t origin_y,
+	subpixel_t length,
+	int angle
+)
+{
+	_BX = angle;
+	#if (GAME == 5)
+		_BH ^= _BH;
+	#endif
+	_BX += _BX; // *= sizeof(short)
+	ret.x.v = polar_x_fast_unsafe(origin_x, length, _BX);
+	ret.y.v = polar_y_fast_unsafe(origin_y, length, _BX);
+}
+
+}
diff --git a/th04/math/vector.hpp b/th04/math/vector.hpp
index 0590465f..b7241784 100644
--- a/th04/math/vector.hpp
+++ b/th04/math/vector.hpp
@@ -7,7 +7,7 @@ int pascal near vector2_near(
 	SPPoint near &ret, unsigned char angle, int length
 );
 
-int pascal vector2_at(
+void pascal vector2_at(
 	SPPoint near &ret,
 	subpixel_t origin_x,
 	subpixel_t origin_y,
diff --git a/th04/vector.cpp b/th04/vector.cpp
new file mode 100644
index 00000000..6077793c
--- /dev/null
+++ b/th04/vector.cpp
@@ -0,0 +1 @@
+#include "th04/math/vector.cpp"
diff --git a/th05/vector.cpp b/th05/vector.cpp
new file mode 100644
index 00000000..6077793c
--- /dev/null
+++ b/th05/vector.cpp
@@ -0,0 +1 @@
+#include "th04/math/vector.cpp"
diff --git a/th05_main.asm b/th05_main.asm
index 2513aa05..2a49382b 100644
--- a/th05_main.asm
+++ b/th05_main.asm
@@ -10559,8 +10559,8 @@ include th04/formats/cdg_put_noalpha.asm
 include th04/snd/se.asm
 include th04/formats/cdg_put.asm
 include th02/exit.asm
-include th04/math/vector1_at.asm
-include th04/math/vector2_at.asm
+	extern VECTOR1_AT:proc
+	extern VECTOR2_AT:proc
 	extern SND_LOAD:proc
 	extern SND_KAJA_INTERRUPT:proc
 	extern GAME_INIT_MAIN:proc
diff --git a/th05_maine.asm b/th05_maine.asm
index bc1d6ec9..d66aab10 100644
--- a/th05_maine.asm
+++ b/th05_maine.asm
@@ -7533,8 +7533,7 @@ include th04/formats/cdg_put_noalpha.asm
 include th04/snd/se.asm
 include th04/hardware/bgimage.asm
 include th02/exit.asm
-include th04/math/vector1_at.asm
-include th04/math/vector2_at.asm
+	extern VECTOR2_AT:proc
 	extern BGIMAGE_PUT_RECT:proc
 	extern SND_LOAD:proc
 	extern SND_KAJA_INTERRUPT:proc
diff --git a/th05_op.asm b/th05_op.asm
index 9c996108..3844bea4 100644
--- a/th05_op.asm
+++ b/th05_op.asm
@@ -2535,8 +2535,7 @@ include th04/snd/se.asm
 include th04/hardware/bgimage.asm
 include th04/formats/cdg_put.asm
 include th02/exit.asm
-include th04/math/vector1_at.asm
-include th04/math/vector2_at.asm
+	extern VECTOR1_AT:proc
 	extern _piano_render:proc
 	extern _piano_setup_and_put_initial:proc
 	extern BGIMAGE_PUT_RECT:proc