[Decompilation] [th01] Unused function to snap all dots with hardware…

… color #4

That's… pretty specific. The only thing on the main menu with this
color is the "1996 ZUN" text at the bottom… probably part of an
effect that we never got to see. Every other idea would be baseless
speculation, given that the snapped buffer isn't used anywhere else.

Part of P0090, funded by Yanga.

Makefile.mak

@@ -48,7 +48,7 @@ bin\Pipeline\grzview.com: Pipeline\grzview.cpp th01\formats\grz.cpp
 bin\th01\zunsoft.com: th01\zunsoft.c
 	$(CC) $(CFLAGS) -mt -lt -nbin\th01\ $** masters.lib
 
-bin\th01\op.exe: bin\th01\op.obj th01\op_02.c th01\op_03.c th01\op_04.c th01\op_05.c th01\op_06.cpp th01\op_07.cpp th01\op_08.c th01\op_09.cpp th01\op_10.c th01\op_11.c th01\op_12.cpp
+bin\th01\op.exe: bin\th01\op.obj th01\op_01.cpp th01\op_02.c th01\op_03.c th01\op_04.c th01\op_05.c th01\op_06.cpp th01\op_07.cpp th01\op_08.c th01\op_09.cpp th01\op_10.c th01\op_11.c th01\op_12.cpp
 	$(CC) $(CFLAGS) -ml -3 -DGAME=1 -DBINARY='O' -nbin\th01\ -eOP.EXE @&&|
 $**
 |

th01/op_01.cpp

@@ -0,0 +1,39 @@
+/* ReC98
+ * -----
+ * Code segment #1 of TH01's OP.EXE
+ */
+
+extern "C" {
+#include "ReC98.h"
+#include "th01/hardware/graph.h"
+
+// Unused. The only thing on the main menu with this color is the "1996 ZUN"
+// text at the bottom... probably part of an effect that we never got to see.
+void snap_col_4(void)
+{
+	extern dots8_t* columns[ROW_SIZE];
+	register int x;
+	register int y;
+	int vram_offset;
+
+	for(x = 0; x < ROW_SIZE; x++) {
+		columns[x] = new dots8_t[RES_Y];
+	}
+	grcg_setcolor_tdw(4);
+	graph_accesspage_func(1);
+
+	for(x = 0; x < ROW_SIZE; x++) {
+		y = 0;
+		vram_offset = x;
+		while(y < RES_Y) {
+			columns[x][y] = VRAM_PLANE_B[vram_offset];
+			y++;
+			vram_offset += ROW_SIZE;
+		}
+	}
+
+	grcg_off();
+	graph_accesspage_func(0);
+}
+
+}

th01_op.asm

@@ -55,6 +55,8 @@ include th01/th01.inc
 	extern _toupper:proc
 	extern _vsprintf:proc
 
+op_01 group op_01_TEXT, op_01__TEXT
+
 ; ===========================================================================
 
 ; Segment type:	Pure code
@@ -89,71 +91,12 @@ _TEXT		ends
 
 ; Segment type:	Pure code
 op_01_TEXT	segment	byte public 'CODE' use16
-		assume cs:op_01_TEXT
+op_01_TEXT	ends
+
+op_01__TEXT	segment	byte public 'CODE' use16
+		assume cs:op_01
 		;org 4
 		assume es:nothing, ss:nothing, ds:_DATA, fs:nothing, gs:nothing
-		enter	2, 0
-		push	si
-		push	di
-		xor	si, si
-		jmp	short loc_A1E5
-; ---------------------------------------------------------------------------
-
-loc_A1CE:
-		push	190h
-		call	@$bnwa$qui
-		pop	cx
-		mov	bx, si
-		shl	bx, 2
-		mov	[bx+118Eh], dx
-		mov	[bx+118Ch], ax
-		inc	si
-
-loc_A1E5:
-		cmp	si, 50h	; 'P'
-		jl	short loc_A1CE
-		call	_grcg_setcolor_tdw stdcall, 4
-		push	1
-		call	_graph_accesspage_func
-		add	sp, 4
-		xor	si, si
-		jmp	short loc_A22A
-; ---------------------------------------------------------------------------
-
-loc_A1FF:
-		xor	di, di
-		mov	[bp-2],	si
-		jmp	short loc_A223
-; ---------------------------------------------------------------------------
-
-loc_A206:
-		les	bx, _VRAM_PLANE_B
-		add	bx, [bp-2]
-		mov	al, es:[bx]
-		mov	bx, si
-		shl	bx, 2
-		les	bx, [bx+118Ch]
-		add	bx, di
-		mov	es:[bx], al
-		inc	di
-		add	word ptr [bp-2], 50h ; 'P'
-
-loc_A223:
-		cmp	di, 190h
-		jl	short loc_A206
-		inc	si
-
-loc_A22A:
-		cmp	si, 50h	; 'P'
-		jl	short loc_A1FF
-		call	_grcg_off_func
-		push	0
-		call	_graph_accesspage_func
-		pop	cx
-		pop	di
-		pop	si
-		leave
-		retf
 
 ; =============== S U B	R O U T	I N E =======================================
 
@@ -952,9 +895,9 @@ sub_A8AD	proc far
 		les	bx, _resident
 		cmp	es:[bx+reiidenconfig_t.stage], 0
 		jnz	short loc_A8E1
-		mov	ax, seg	op_01_TEXT
+		mov	ax, seg	op_01
 		mov	es, ax
-		assume es:op_01_TEXT
+		assume es:op_01
 
 loc_A8E1:
 		call	sub_A79D
@@ -2040,7 +1983,7 @@ loc_B25D:
 		leave
 		retf
 _main		endp
-op_01_TEXT	ends
+op_01__TEXT	ends
 
 ; ===========================================================================
 
@@ -2460,7 +2403,8 @@ include th01/mdrv2[data].asm
 
 ; TODO: Missing clip[bss].asm (16 bytes) somewhere in there...
 dword_13418	dd ?
-		db 320 dup(?)
+public _columns
+_columns	dd ROW_SIZE dup (?)
 include th01/hardware/vsync[bss].asm
 		db 191 dup (?)
 word_13627	dw ?