diff --git a/libs/master.lib/text_boxfilla.asm b/libs/master.lib/text_boxfilla.asm
new file mode 100644
index 00000000..716ea59e
--- /dev/null
+++ b/libs/master.lib/text_boxfilla.asm
@@ -0,0 +1,95 @@
+; master library - PC98
+;
+; Description:
+;	テキスト画面の長方形範囲を指定属性で埋める
+;
+; Function/Procedures:
+;	void text_boxfilla( unsigned x1, unsigned y1, unsigned x2, unsigned y2,
+;				unsigned atrb ) ;
+;
+; Parameters:
+;	unsigned x1	左端の横座標( 0 〜 79 )
+;	unsigned y1	上端の縦座標( 0 〜 24 )
+;	unsigned x2	右端の横座標( 0 〜 79 )
+;	unsigned y2	下端の縦座標( 0 〜 24 )
+;	unsigned atrb	属性
+;
+; Returns:
+;	none
+;
+; Binding Target:
+;	Microsoft-C / Turbo-C / Turbo Pascal
+;
+; Running Target:
+;	PC-9801
+;
+; Requiring Resources:
+;	CPU: 8086
+;
+; Notes:
+;	x1 <= x2 かつ y1 <= y2でなければならない。
+;
+; Compiler/Assembler:
+;	TASM 3.0
+;	OPTASM 1.6
+;
+; Author:
+;	恋塚昭彦
+;
+; Revision History:
+;	92/11/15 Initial
+
+func TEXT_BOXFILLA
+	push	DI
+	pushf
+	CLI
+	add	SP,(2+retsize)*2
+			; パラメータ領域の先頭( flags,DI,retadr )
+
+	pop	AX	; color
+	pop	DX	; y2
+	pop	BX	; x2
+	pop	CX	; Y1
+
+	mov	DI,CX
+	shl	DI,1
+	shl	DI,1
+	add	DI,CX
+	shl	DI,1
+	add	DI,TextVramSeg
+	add	DI,200h
+	mov	ES,DI	; これで ESに (0,y1)のテキスト属性セグメントが入った
+
+	pop	DI	; X1
+
+	sub	SP,(5+2+retsize)*2
+			; (5(ﾊﾟﾗﾒｰﾀの数)+1(ﾘﾀｰﾝｱﾄﾞﾚｽ)+2(DI,flags))*2
+	popf
+
+	sub	BX,DI	; BX = X2 - X1 + 1
+	inc	BX	;
+
+	sub	DX,CX
+	mov	CX,DX
+	shl	DX,1
+	shl	DX,1
+	add	DX,CX
+	shl	DX,1
+	shl	DX,1
+	shl	DX,1
+	shl	DX,1
+	add	DI,DX
+	shl	DI,1	; これで DI には(x1,y2)のoffsetが入った。
+
+	lea	DX,[BX+80]
+	shl	DX,1	; 毎回の減少分
+
+	EVEN
+@@SLOOP:		mov     CX,BX
+		rep stosw	; 一行分の書き込み
+		sub     DI,DX	; 下の行に移動
+	jnb	short @@SLOOP
+
+	pop	DI
+	ret	10
+endfunc
diff --git a/th02_main.asm b/th02_main.asm
index 82a2c5e9..5dc50b5b 100644
--- a/th02_main.asm
+++ b/th02_main.asm
@@ -1477,56 +1477,7 @@ include libs/master.lib/random.asm
 include libs/master.lib/rottbl.asm
 include libs/master.lib/smem_release.asm
 include libs/master.lib/smem_wget.asm
-
-; =============== S U B	R O U T	I N E =======================================
-
-
-sub_25DA	proc far
-		push	di
-		pushf
-		cli
-		add	sp, 8
-		pop	ax
-		pop	dx
-		pop	bx
-		pop	cx
-		mov	di, cx
-		shl	di, 1
-		shl	di, 1
-		add	di, cx
-		shl	di, 1
-		add	di, TextVramSeg
-		add	di, 200h
-		mov	es, di
-		pop	di
-		sub	sp, 12h
-		popf
-		sub	bx, di
-		inc	bx
-		sub	dx, cx
-		mov	cx, dx
-		shl	dx, 1
-		shl	dx, 1
-		add	dx, cx
-		shl	dx, 1
-		shl	dx, 1
-		shl	dx, 1
-		shl	dx, 1
-		add	di, dx
-		shl	di, 1
-		lea	dx, [bx+50h]
-		shl	dx, 1
-		nop
-
-loc_261C:
-		mov	cx, bx
-		rep stosw
-		sub	di, dx
-		jnb	short loc_261C
-		pop	di
-		retf	0Ah
-sub_25DA	endp
-
+include libs/master.lib/text_boxfilla.asm
 include libs/BorlandC/text_clear.asm
 include libs/master.lib/text_fillca.asm
 
@@ -8198,7 +8149,7 @@ loc_B8B5:
 		push	large 40001h
 		push	large 330017h
 		push	5
-		call	sub_25DA
+		call	text_boxfilla
 		push	30h ; '0'       ; n
 		push	ds
 		push	offset unk_1F4AD ; src
diff --git a/th03_main.asm b/th03_main.asm
index 01047fe7..3722fc06 100644
--- a/th03_main.asm
+++ b/th03_main.asm
@@ -1551,56 +1551,7 @@ loc_1F83:
 		retn
 sub_1F78	endp
 
-
-; =============== S U B	R O U T	I N E =======================================
-
-
-sub_1F8C	proc far
-		push	di
-		pushf
-		cli
-		add	sp, 8
-		pop	ax
-		pop	dx
-		pop	bx
-		pop	cx
-		mov	di, cx
-		shl	di, 1
-		shl	di, 1
-		add	di, cx
-		shl	di, 1
-		add	di, TextVramSeg
-		add	di, 200h
-		mov	es, di
-		pop	di
-		sub	sp, 12h
-		popf
-		sub	bx, di
-		inc	bx
-		sub	dx, cx
-		mov	cx, dx
-		shl	dx, 1
-		shl	dx, 1
-		add	dx, cx
-		shl	dx, 1
-		shl	dx, 1
-		shl	dx, 1
-		shl	dx, 1
-		add	di, dx
-		shl	di, 1
-		lea	dx, [bx+50h]
-		shl	dx, 1
-		nop
-
-loc_1FCE:
-		mov	cx, bx
-		rep stosw
-		sub	di, dx
-		jnb	short loc_1FCE
-		pop	di
-		retf	0Ah
-sub_1F8C	endp
-
+include libs/master.lib/text_boxfilla.asm
 include libs/BorlandC/text_clear.asm
 include libs/master.lib/text_fillca.asm
 
@@ -8406,11 +8357,11 @@ sub_B8F7	proc far
 		push	large 20001h
 		push	large 250018h
 		push	0E1h ; '�'
-		call	sub_1F8C
+		call	text_boxfilla
 		push	large 2A0001h
 		push	large 4D0018h
 		push	0E1h ; '�'
-		call	sub_1F8C
+		call	text_boxfilla
 		pop	bp
 		retf
 sub_B8F7	endp
diff --git a/th05_main.asm b/th05_main.asm
index aee09b59..a7531387 100644
--- a/th05_main.asm
+++ b/th05_main.asm
@@ -1586,60 +1586,7 @@ loc_249F:
 		retn
 sub_2494	endp
 
-
-; =============== S U B	R O U T	I N E =======================================
-
-
-sub_24A8	proc far
-		push	di
-		pushf
-		cli
-		add	sp, 8
-		pop	ax
-		pop	dx
-		pop	bx
-		pop	cx
-		mov	di, cx
-		shl	di, 1
-		shl	di, 1
-		add	di, cx
-		shl	di, 1
-		add	di, TextVramSeg
-		add	di, 200h
-		mov	es, di
-		pop	di
-		sub	sp, 12h
-		popf
-		sub	bx, di
-		inc	bx
-		sub	dx, cx
-		mov	cx, dx
-		shl	dx, 1
-		shl	dx, 1
-		add	dx, cx
-		shl	dx, 1
-		shl	dx, 1
-		shl	dx, 1
-		shl	dx, 1
-		add	di, dx
-		shl	di, 1
-		lea	dx, [bx+50h]
-		shl	dx, 1
-		nop
-
-loc_24EA:
-		mov	cx, bx
-		rep stosw
-
-loc_24EE:
-		sub	di, dx
-		jnb	short loc_24EA
-		pop	di
-
-locret_24F3:
-		retf	0Ah
-sub_24A8	endp
-
+include libs/master.lib/text_boxfilla.asm
 include libs/BorlandC/text_clear.asm
 include libs/master.lib/text_fillca.asm
 
@@ -15222,11 +15169,11 @@ loc_F1F2:
 		push	large 140014h
 		push	large 320017h
 		push	21h ; '!'
-		call	sub_24A8
+		call	text_boxfilla
 		push	large 6000Ch
 		push	large 24000Fh
 		push	21h ; '!'
-		call	sub_24A8
+		call	text_boxfilla
 		push	word_2C934
 		push	word_2C936
 		call	sub_EF74