[Reverse-engineering] [th04/th05] GRCG-powered playfield row filling

Isn't it quite a bit risky to do that without a CLD in front? Funded by zorg.
2018-12-21 23:03:25 +01:00 · 2018-12-21 23:03:25 +01:00 · d211a22c9f
parent bc3c85f09a
commit d211a22c9f
4 changed files with 42 additions and 117 deletions
--- a/th04/hardware/grcg.inc
+++ b/th04/hardware/grcg.inc
@ -22,3 +22,11 @@ GRCG_SETCOLOR_DIRECT_NOINT_DEF macro instance
 		ret
 	_grcg_setcolor_direct_noint_&instance	endp
 endm
+
+; Convenience macro to prepare ES:DI.
+GRCG_FILL_PLAYFIELD_ROWS	macro y:req, num_rows:req, scratch_sgm:=<ax>
+	mov	scratch_sgm, GRAM_400 + (((y + PLAYFIELD_Y) * ROW_SIZE) shr 4)
+	mov	es, scratch_sgm
+	mov	di, ((num_rows - 1) * ROW_SIZE) + PLAYFIELD_VRAM_X
+	call	_grcg_fill_playfield_rows
+endm
--- a/th04/hardware/grcg_fill_rows.asm
+++ b/th04/hardware/grcg_fill_rows.asm
@ -0,0 +1,14 @@
+; Fills the given playfield rows between ES:0 (top row) and ES:DI (left byte
+; in the bottom row) with the current GRCG tile.
+; Assumes that the GRCG is set to TDW mode.
+
+; void __usercall grcg_fill_playfield_rows(void far *vram_byte_at_bottom_left<es:di>);
+public _grcg_fill_playfield_rows
+_grcg_fill_playfield_rows	proc near
+	mov	cx, PLAYFIELD_VRAM_W / 4
+	rep stosd
+	sub	di, ROW_SIZE + PLAYFIELD_VRAM_W
+	jge	short _grcg_fill_playfield_rows
+	retn
+_grcg_fill_playfield_rows	endp
+	even
--- a/th04_main.asm
+++ b/th04_main.asm
@ -2525,11 +2525,7 @@ sub_BE68	endp

 sub_BECC	proc near
 		push	di
-		mov	ax, GRAM_400 + ((112 + PLAYFIELD_Y) * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (255 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	112, 256
 		pop	di
 		retn
 sub_BECC	endp
@ -2719,11 +2715,7 @@ loc_C002:
 		stosd
 		sub	di, ROW_SIZE + 12
 		jge	short loc_C002
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (111 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	0, 112
 		pop	di
 		retn
 sub_BFF8	endp
@ -2924,11 +2916,7 @@ sub_C0FC	endp

 sub_C148	proc near
 		push	di
-		mov	ax, GRAM_400 + (((192 + PLAYFIELD_Y) * ROW_SIZE) shr 4)
-		mov	es, ax
-		assume es:nothing
-		mov	di, (175 * ROW_SIZE) + 4
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	192, 176
 		pop	di
 		retn
 sub_C148	endp
@ -8316,16 +8304,8 @@ sub_E8A3	endp

 sub_EA70	proc near
 		push	di
-		mov	ax, GRAM_400 + ((192 + PLAYFIELD_Y) * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (191 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (79 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	192, 192
+		GRCG_FILL_PLAYFIELD_ROWS	  0,  80
 		pop	di
 		retn
 sub_EA70	endp
@ -8801,11 +8781,7 @@ sub_ED71	endp

 sub_EDE2	proc near
 		push	di
-		mov	dx, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, dx
-		assume es:nothing
-		mov	di, (119 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	  0, 120, dx
 		cli
 		mov	dx, 7Eh	; '~'
 		xor	al, al
@ -8814,11 +8790,7 @@ sub_EDE2	proc near
 		out	dx, al
 		out	dx, al
 		sti
-		mov	ax, GRAM_400 + ((248 + PLAYFIELD_Y) * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (119 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	248, 120
 		pop	di
 		retn
 sub_EDE2	endp
@ -15178,16 +15150,8 @@ sub_11FC8	endp

 sub_1200A	proc near
 		push	di
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (39 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
-		mov	ax, GRAM_400 + (((314 + PLAYFIELD_Y) * ROW_SIZE) shr 4)
-		mov	es, ax
-		assume es:nothing
-		mov	di, (53 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	  0, 40
+		GRCG_FILL_PLAYFIELD_ROWS	314, 54
 		pop	di
 		retn
 sub_1200A	endp
@ -15234,29 +15198,12 @@ sub_12024	endp

 sub_1205A	proc near
 		push	di
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (PLAYFIELD_H - 1) * ROW_SIZE + PLAYFIELD_VRAM_X
-		call	sub_12068
+		GRCG_FILL_PLAYFIELD_ROWS	0, PLAYFIELD_H
 		pop	di
 		retn
 sub_1205A	endp

-
-; =============== S U B	R O U T	I N E =======================================
-
-
-sub_12068	proc near
-		mov	cx, 0Ch
-		rep stosd
-		sub	di, 80h
-		jge	short sub_12068
-		retn
-sub_12068	endp
-
-; ---------------------------------------------------------------------------
-		nop
+include th04/hardware/grcg_fill_rows.asm

 ; =============== S U B	R O U T	I N E =======================================

--- a/th05_main.asm
+++ b/th05_main.asm
@ -4558,20 +4558,7 @@ sub_CFEE	proc near
 		retn
 sub_CFEE	endp

-
-; =============== S U B	R O U T	I N E =======================================
-
-
-sub_D024	proc near
-		mov	cx, 0Ch
-		rep stosd
-		sub	di, 80h
-		jge	short sub_D024
-		retn
-sub_D024	endp
-
-; ---------------------------------------------------------------------------
-		nop
+include th04/hardware/grcg_fill_rows.asm

 ; =============== S U B	R O U T	I N E =======================================

@ -6349,11 +6336,7 @@ sub_DD42	proc near
 		out	dx, al
 		out	dx, al
 		sti
-		mov	dx, GRAM_400 + (((192 + PLAYFIELD_Y) * ROW_SIZE) shr 4)
-		mov	es, dx
-		assume es:nothing
-		mov	di, (175 * ROW_SIZE) + 4
-		call	sub_D024
+		GRCG_FILL_PLAYFIELD_ROWS	192, 176, dx
 		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
 		mov	es, ax
 		assume es:nothing
@ -6592,11 +6575,7 @@ sub_DE7A	endp

 sub_DEA6	proc near
 		push	di
-		mov	ax, GRAM_400 + (((192 + PLAYFIELD_Y) * ROW_SIZE) shr 4)
-		mov	es, ax
-		assume es:nothing
-		mov	di, (175 * ROW_SIZE) + 4
-		call	sub_D024
+		GRCG_FILL_PLAYFIELD_ROWS	192, 176
 		pop	di
 		retn
 sub_DEA6	endp
@ -6607,11 +6586,7 @@ sub_DEA6	endp

 sub_DEB4	proc near
 		push	di
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (204 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_D024
+		GRCG_FILL_PLAYFIELD_ROWS	  0, 205
 		pop	di
 		retn
 sub_DEB4	endp
@ -6827,11 +6802,7 @@ sub_DFBA	endp

 sub_E01E	proc near
 		push	di
-		mov	ax, GRAM_400 + (((192 + PLAYFIELD_Y) * ROW_SIZE) shr 4)
-		mov	es, ax
-		assume es:nothing
-		mov	di, (175 * ROW_SIZE) + 4
-		call	sub_D024
+		GRCG_FILL_PLAYFIELD_ROWS	192, 176
 		pop	di
 		retn
 sub_E01E	endp
@ -8148,16 +8119,8 @@ sub_E8FE	endp

 sub_E914	proc near
 		push	di
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (103 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_D024
-		mov	ax, GRAM_400 + ((296 + PLAYFIELD_Y) * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (71 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_D024
+		GRCG_FILL_PLAYFIELD_ROWS	  0, 104
+		GRCG_FILL_PLAYFIELD_ROWS	296,  72
 		pop	di
 		retn
 sub_E914	endp
@ -8180,11 +8143,7 @@ sub_E92E	proc near
 		out	dx, al
 		popf
 		push	di
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		assume es:nothing
-		mov	di, (PLAYFIELD_H - 1) * ROW_SIZE + PLAYFIELD_VRAM_X
-		call	sub_D024
+		GRCG_FILL_PLAYFIELD_ROWS	0, PLAYFIELD_H
 		GRCG_OFF_VIA_XOR al
 		pop	di
 		retn
@ -8206,10 +8165,7 @@ sub_E950	proc near
 		out	dx, al
 		popf
 		push	di
-		mov	ax, GRAM_400 + (PLAYFIELD_Y * ROW_SIZE) shr 4
-		mov	es, ax
-		mov	di, (239 * ROW_SIZE) + PLAYFIELD_VRAM_X
-		call	sub_D024
+		GRCG_FILL_PLAYFIELD_ROWS	0, 240
 		GRCG_OFF_VIA_XOR al
 		pop	di
 		retn