X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fvdp.S;h=990a3ef61311d8625226af1c808f734fd8e29287;hb=ce93735c3abce87854765403972df1d26382dd85;hp=1d62565be51705d4c6a41d44f928e8602f6d06fb;hpb=88989dba0a2f0b59d782d25e01227df04452e8d3;p=mdlife

diff --git a/src/vdp.S b/src/vdp.S
index 1d62565..990a3ef 100644
--- a/src/vdp.S
+++ b/src/vdp.S
@@ -4,29 +4,39 @@
 
 	.globl vdp_init
 vdp_init:
-	| initialize registers
-	move.l #def_reg_tab, %a0
-	clr.w %d1
-0:	move.w %d1, %d0
-	lsl.w #8, %d0
+	movea.l #def_reg_tab, %a0
+	moveq #14, %d1
+0:	move.w (%a0)+, %d0
 	or.w #0x8000, %d0
-	move.b (%a0)+, %d0
 	move.w %d0, VDP_CTL_PORT	| VDP_CTL = 0x8000 | (reg << 8) | val
-	add.w #1, %d1
-	cmp.w def_reg_tab_size, %d1
-	bne.s 0b
+	dbra %d1, 0b
 
-	| clear VRAM
-	clr.l %d0
+	| clear vram
+	movea.l #VDP_DATA_PORT, %a0
+	moveq #0, %d0
 	move.l #VDP_VRAM, %d1
 	bsr setup_addr
-	clr.w %d0
-	move.w #0xffff, %d1
-0:	move.w %d0, VDP_DATA_PORT
-	dbra.w %d1, 0b
-	
-	rts
+	moveq #0, %d0
+	move.l #0x7fff, %d1	| 64k / 2 - 1
+0:	move.w %d0, (%a0)
+	dbra %d1, 0b
 
+	| clear colormaps
+	move.l #VDP_CRAM, %d1
+	bsr setup_addr
+	moveq #0, %d0
+	move.l #63, %d1		| 4 palettes * 16 col * 2 bytes / 2 - 1
+0:	move.w %d0, (%a0)
+	dbra %d1, 0b
+
+	| clear vscroll
+	move.l #VDP_VSRAM, %d1
+	bsr setup_addr
+	moveq #0, %d0
+	move.l #39, %d1		| 80 bytes / 2 - 1
+0:	move.w %d0, (%a0)
+	dbra %d1, 0b
+	rts
 
 	| address in d0, type in d1
 setup_addr:
@@ -56,28 +66,24 @@ vdp_setcolor:
 
 	.section .rodata
 def_reg_tab:
-	.byte VDP_M1_INIT			| 0: mode 1
-	.byte VDP_M2_INIT + VDP_M2_DISP		| 1: mode 2
-	.byte VDP_NA_ADDR(0xc000)		| 2: scroll A nametable addr.
-	.byte VDP_NW_ADDR(VDP_ADDR_INVAL)	| 3: window nametable addr.
-	.byte VDP_NB_ADDR(0xd000)		| 4: scroll B nametable addr.
-	.byte VDP_SPRTAB_ADDR(0xe000)		| 5: sprite table addr.
-	.byte 0
-	.byte 0					| 7: bg color
-	.byte 0, 0
-	.byte 0					| 10: horiz. interrupt interval
-	.byte 0					| 11: mode 3
-	.byte VDP_M4_H40			| 12: mode 4
-	.byte 0					| 13: hscroll table addr.
-	.byte 0
-	.byte 2					| 15: autoincrement 2 bytes
-	.byte VDP_SCR_H64			| 16: scroll size (64x32)
-	.byte 0, 0				| 17,18: win x/y pos
-	.byte 0, 0, 0, 0, 0			| 19-23: DMA regs
-def_reg_tab_end:
-	.align 2
-def_reg_tab_size:
-	.word def_reg_tab_end - def_reg_tab
+	.byte VDP_REG_MODE1, VDP_M1_INIT		| 0: mode 1
+	.byte VDP_REG_MODE2, VDP_M2_INIT + VDP_M2_DISP	| 1: mode 2
+	.byte VDP_REG_NAMEA, VDP_NA_ADDR(0xc000)	| 2: scroll A nametable addr.
+	.byte VDP_REG_NAMEW, 0				| 3: window nametable addr.
+	.byte VDP_REG_NAMEB, VDP_NB_ADDR(0xd000)	| 4: scroll B nametable addr.
+	.byte VDP_REG_SPR, VDP_SPRTAB_ADDR(0xe000)	| 5: sprite table addr.
+	.byte VDP_REG_BGCOL, 0				| 7: bg color
+	.byte VDP_REG_HINTR, 0				| 10: horiz. interrupt interval
+	.byte VDP_REG_MODE3, 0				| 11: mode 3
+	.byte VDP_REG_MODE4, VDP_M4_H40			| 12: mode 4
+	.byte VDP_REG_HSCROLL, VDP_HSTAB_ADDR(0xf000)	| 13: hscroll table addr.
+	.byte VDP_REG_AUTOINC, 2			| 15: autoincrement 2 bytes
+	.byte VDP_REG_SCROLLSZ, VDP_SCR_H64		| 16: scroll size (64x32)
+	.byte VDP_REG_WINX, 0, VDP_REG_WINY, 0		| 17,18: win x/y pos
+	| zeroing the DMA registers at this point causes the real machine to
+	| hang, so skip them.
+	|.byte VDP_REG_DMACNTL, 0, VDP_REG_DMACNTH, 0	| 19-23: DMA regs
+	|.byte VDP_REG_DMASRCL, 0, VDP_REG_DMASRCM, 0, VDP_REG_DMASRCH, 0	
 
 	
 | vi:ft=gas68k: