diff --git a/master.hpp b/master.hpp
index 42b1a5a7..71abe558 100644
--- a/master.hpp
+++ b/master.hpp
@@ -176,7 +176,9 @@ void MASTER_RET grcg_off(void);
 	void MASTER_RET grcg_round_boxfill(
 		int x1, int y1, int x2, int y2, unsigned r
 	);
-	void MASTER_RET grcg_byteboxfill_x(int x1, int y1, int x2, int y2);
+	void MASTER_RET grcg_byteboxfill_x(
+		vram_x_t left, vram_y_t top, vram_x_t right, vram_y_t bottom
+	);
 
 	// Circles
 	void MASTER_RET grcg_circle(int x, int y, unsigned r);
@@ -289,6 +291,11 @@ void MASTER_RET vsync_end(void);
 
 /// Inlined extensions
 /// ------------------
+#define grcg_boxfill_8(left, top, right, bottom) \
+	grcg_byteboxfill_x( \
+		((left) / BYTE_DOTS), top, ((right) / BYTE_DOTS), bottom \
+	)
+
 #define palette_entry_rgb_show(fn) \
 	palette_entry_rgb(fn); \
 	palette_show();
diff --git a/th05/m_char.cpp b/th05/m_char.cpp
index 56f18e29..4154c0c8 100644
--- a/th05/m_char.cpp
+++ b/th05/m_char.cpp
@@ -6,7 +6,11 @@
 #pragma codeseg op_01_TEXT
 
 extern "C" {
-#include "ReC98.h"
+#include <dos.h>
+#include "platform.h"
+#include "pc98.h"
+#include "planar.h"
+#include "master.hpp"
 #include "th01/ranks.h"
 #include "th02/hardware/frmdelay.h"
 #include "th04/formats/cdg.h"
@@ -112,16 +116,16 @@ void pascal near pic_put(bool16 darkened)
 
 		// Drop shadow
 		grcg_setcolor(GC_RMW, 1);
-		grcg_byteboxfill_x(
-			((pic_raised_left + PIC_W) / BYTE_DOTS),
+		grcg_boxfill_8(
+			(pic_raised_left + PIC_W),
 			pic_top,
-			((pic_left + PIC_W - 1) / BYTE_DOTS),
+			(pic_left + PIC_W - 1),
 			(pic_raised_top + PIC_H - 1)
 		);
-		grcg_byteboxfill_x(
-			(pic_left / BYTE_DOTS),
+		grcg_boxfill_8(
+			pic_left,
 			(pic_raised_top + PIC_H),
-			((pic_left + PIC_W - 1) / BYTE_DOTS),
+			(pic_left + PIC_W - 1),
 			(pic_top + PIC_H - 1)
 		);
 		grcg_off();