[Reduction] #426: graph_200line

Yup. TH03's graphics layer is actually set to a resolution of 640x200 and
upscaled by the hardware, which gives the game its distinctive low-res look.

libs/master.lib/graph_200line.asm

@@ -0,0 +1,77 @@
+; master library - PC98
+;
+; Description:
+;	グラフィック画面を 200lineに設定する
+;
+; Function/Procedures:
+;	void graph_200line( int tail ) ;
+;
+; Parameters:
+;	int	tail	0 = 上半分、 1 = 下半分
+;
+; Returns:
+;	none
+;
+; Binding Target:
+;	Microsoft-C / Turbo-C / Turbo Pascal
+;
+; Running Target:
+;	PC-9801
+;
+; Requiring Resources:
+;	CPU: 8086
+;
+; Notes:
+;	同時にアクセスページを 0 に設定します。
+;
+; Compiler/Assembler:
+;	TASM 3.0
+;	OPTASM 1.6
+;
+; Author:
+;	恋塚昭彦
+;
+; Revision History:
+;	92/11/16 Initial
+;	93/ 3/27 gc_poly.lib合併
+;	94/ 1/22 [M0.22] graph_VramZoom対応
+
+func GRAPH_200LINE
+	mov	BX,SP
+	mov	BX,SS:[BX+RETSIZE*2]
+	mov	CX,BX
+	ror	CX,1
+	cmc
+	rcr	CX,1
+	mov	AH,42h
+	int	18h
+
+	mov	AL,8	; 高密度
+	out	68h,AL
+
+	mov	AX,0a800h
+	or	BX,BX
+	jz	short @@SKIP
+	mov	AX,0abe8h
+@@SKIP:
+	mov	graph_VramSeg,AX
+	mov	ClipYT_Seg,AX
+
+	mov	AX,0
+	mov	ClipXL,AX
+	mov	ClipYT,AX
+	mov	AX,639
+	mov	ClipXR,AX
+	mov	ClipXW,AX
+
+	mov	graph_VramWords,8000
+	mov	AX,200
+	mov	graph_VramLines,AX
+	dec	AX
+	mov	ClipYB,AX
+	mov	ClipYH,AX
+	mov	ClipYB_adr,(80*199)
+	mov	graph_VramZoom,1	; GDC 2.5MHz固定, zoom 1bit(2倍)
+
+	ret	2
+endfunc

th03_main.asm

@@ -152,48 +152,7 @@ include libs/master.lib/gaiji_putca.asm
 include libs/master.lib/gaiji_putsa.asm
 include libs/master.lib/gaiji_read.asm
 include libs/master.lib/gaiji_write.asm
-
-; =============== S U B	R O U T	I N E =======================================
-
-
-sub_1402	proc far
-		mov	bx, sp
-		mov	bx, ss:[bx+4]
-		mov	cx, bx
-		ror	cx, 1
-		cmc
-		rcr	cx, 1
-		mov	ah, 42h	; 'B'
-		int	18h		; TRANSFER TO ROM BASIC
-					; causes transfer to ROM-based BASIC (IBM-PC)
-					; often	reboots	a compatible; often has	no effect at all
-		mov	al, 8
-		out	68h, al
-		mov	ax, 0A800h
-		or	bx, bx
-		jz	short loc_1421
-		mov	ax, 0ABE8h
-
-loc_1421:
-		mov	graph_VramSeg, ax
-		mov	ClipYT_seg, ax
-		mov	ax, 0
-		mov	ClipXL, ax
-		mov	ClipYT, ax
-		mov	ax, 27Fh
-		mov	ClipXR, ax
-		mov	ClipXW, ax
-		mov	graph_VramWords, 1F40h
-		mov	ax, 0C8h ; 'È'
-		mov	graph_VramLines, ax
-		dec	ax
-		mov	ClipYB, ax
-		mov	ClipYH, ax
-		mov	ClipYB_adr, 3E30h
-		mov	graph_VramZoom, 1
-		retf	2
-sub_1402	endp
-
+include libs/master.lib/graph_200line.asm
 include libs/master.lib/graph_400line.asm
 include libs/master.lib/graph_clear.asm
 include libs/master.lib/graph_copy_page.asm
@@ -4481,7 +4440,7 @@ loc_9E24:
 		push	cs
 		call	near ptr sub_A38E
 		push	0
-		call	sub_1402
+		call	graph_200line
 		call	sub_F0EE
 		mov	byte_23AEE, 0
 		mov	byte_23AEF, 1