# HG changeset patch
# User Michael Pavone <pavone@retrodev.com>
# Date 1454001014 28800
# Node ID 913a6336ce20b68a2a317b62c19199fd850297fc
# Parent  2be771c4dfbdd9834b5d4ddf9adce2e8febe65e4
Shift slot number to slot behavior mapping by six slots in H40 mode. This makes the line change slot align with the point at which the display turns on and off at the end of the active display area. Also fixed a regression in which an external slot got accidentally changed into a sprite draw slot

diff -r 2be771c4dfbd -r 913a6336ce20 vdp.c
--- a/vdp.c	Tue Jan 26 19:23:10 2016 -0800
+++ b/vdp.c	Thu Jan 28 09:10:14 2016 -0800
@@ -24,7 +24,7 @@
 #define MCLKS_SLOT_H32  20
 #define VINT_SLOT_H40  4 //21 slots before HSYNC, 16 during, 10 after
 #define VINT_SLOT_H32  4  //old value was 23, but recent tests suggest the actual value is close to the H40 one
-#define HSYNC_SLOT_H40  234
+#define HSYNC_SLOT_H40  228
 #define HSYNC_END_H40  (HSYNC_SLOT_H40+17)
 #define HSYNC_END_H32   (33 * MCLKS_SLOT_H32)
 #define HBLANK_START_H40 178 //should be 179 according to Nemesis, but 178 seems to fit slightly better with my test ROM results
@@ -981,25 +981,25 @@
 	case startcyc:\
 		read_map_scroll_a(column, context->vcounter, context);\
 		CHECK_LIMIT\
-	case (startcyc+1):\
+	case ((startcyc+1)&0xFF):\
 		external_slot(context);\
 		CHECK_LIMIT\
-	case (startcyc+2):\
+	case ((startcyc+2)&0xFF):\
 		render_map_1(context);\
 		CHECK_LIMIT\
-	case (startcyc+3):\
+	case ((startcyc+3)&0xFF):\
 		render_map_2(context);\
 		CHECK_LIMIT\
-	case (startcyc+4):\
+	case ((startcyc+4)&0xFF):\
 		read_map_scroll_b(column, context->vcounter, context);\
 		CHECK_LIMIT\
-	case (startcyc+5):\
+	case ((startcyc+5)&0xFF):\
 		read_sprite_x(context->vcounter, context);\
 		CHECK_LIMIT\
-	case (startcyc+6):\
+	case ((startcyc+6)&0xFF):\
 		render_map_3(context);\
 		CHECK_LIMIT\
-	case (startcyc+7):\
+	case ((startcyc+7)&0xFF):\
 		render_map_output(context->vcounter, column, context);\
 		CHECK_LIMIT
 
@@ -1029,7 +1029,7 @@
 		CHECK_LIMIT\
 	case (startcyc+7):\
 		render_map_output(context->vcounter, column, context);\
-		if (column == 40 || (column == 32 && startcyc == 124)) {\
+		if (column == 32 && startcyc == 124) {\
 			vdp_advance_line(context);\
 		}\
 		CHECK_LIMIT
@@ -1041,7 +1041,7 @@
 		if (context->flags & FLAG_DMA_RUN) { run_dma_src(context, context->hslot); } \
 		if (slot == 182) {\
 			context->hslot = 229;\
-			context->cycles += slot_cycles;\
+			context->cycles += h40_hsync_cycles[0];\
 		} else {\
 			context->hslot++;\
 			if (slot >= HSYNC_SLOT_H40 && slot < HSYNC_END_H40) {\
@@ -1075,55 +1075,21 @@
 	{
 	for (;;)
 	{
+	//sprite attribute table scan starts
 	case 165:
-		external_slot(context);
-		CHECK_LIMIT
-	case 166:
-		external_slot(context);
-		CHECK_LIMIT
-	//sprite render to line buffer starts
-	case 167:
-		context->cur_slot = MAX_DRAWS-1;
-		memset(context->linebuf, 0, LINEBUF_SIZE);
-		if (context->vcounter == 0x1FF) {
-			external_slot(context);
-		} else {
-			render_sprite_cells(context);
-		}
-		CHECK_LIMIT
-	case 168:
-		if (context->vcounter == 0x1FF) {
-			external_slot(context);
-		} else {
-			render_sprite_cells(context);
-		}
-		CHECK_LIMIT
-	case 169:
-		if (context->vcounter == 0x1FF) {
-			external_slot(context);
-		} else {
-			render_sprite_cells(context);
-		}
-		CHECK_LIMIT
-	case 170:
-		if (context->vcounter == 0x1FF) {
-			external_slot(context);
-		} else {
-			render_sprite_cells(context);
-			if (context->vcounter == (context->latched_mode & BIT_PAL ? PAL_INACTIVE_START : NTSC_INACTIVE_START)) {
-				context->hslot++;
-				context->cycles += slot_cycles;
-				return;
-			}
-		}
-		CHECK_LIMIT
-	//sprite attribute table scan starts
-	case 171:
 		context->sprite_index = 0x80;
 		context->slot_counter = MAX_SPRITES_LINE;
 		render_sprite_cells( context);
 		scan_sprite_table(context->vcounter, context);
 		CHECK_LIMIT
+	SPRITE_RENDER_H40(166)
+	SPRITE_RENDER_H40(167)
+	case 168:
+		external_slot(context);
+		CHECK_LIMIT
+	SPRITE_RENDER_H40(169)
+	SPRITE_RENDER_H40(170)
+	SPRITE_RENDER_H40(171)
 	SPRITE_RENDER_H40(172)
 	SPRITE_RENDER_H40(173)
 	SPRITE_RENDER_H40(174)
@@ -1134,13 +1100,13 @@
 	SPRITE_RENDER_H40(179)
 	SPRITE_RENDER_H40(180)
 	SPRITE_RENDER_H40(181)
+	//!HSYNC asserted
 	SPRITE_RENDER_H40(182)
 	SPRITE_RENDER_H40(229)
 	SPRITE_RENDER_H40(230)
 	SPRITE_RENDER_H40(231)
 	SPRITE_RENDER_H40(232)
 	SPRITE_RENDER_H40(233)
-	//!HSYNC asserted
 	SPRITE_RENDER_H40(234)
 	SPRITE_RENDER_H40(235)
 	SPRITE_RENDER_H40(236)
@@ -1149,13 +1115,7 @@
 	SPRITE_RENDER_H40(239)
 	SPRITE_RENDER_H40(240)
 	SPRITE_RENDER_H40(241)
-	SPRITE_RENDER_H40(242)
-	SPRITE_RENDER_H40(243)
-	SPRITE_RENDER_H40(244)
-	SPRITE_RENDER_H40(245)
-	SPRITE_RENDER_H40(246)
-	SPRITE_RENDER_H40(247)
-	case 248:
+	case 242:
 		address = (context->regs[REG_HSCROLL] & 0x3F) << 10;
 		mask = 0;
 		if (context->regs[REG_MODE_3] & 0x2) {
@@ -1173,34 +1133,32 @@
 		context->cycles += h40_hsync_cycles[14];
 		CHECK_ONLY
 	//!HSYNC high
-	SPRITE_RENDER_H40(249)
-	SPRITE_RENDER_H40(250)
-	SPRITE_RENDER_H40(251)
-	SPRITE_RENDER_H40(252)
-	case 253:
+	SPRITE_RENDER_H40(243)
+	SPRITE_RENDER_H40(244)
+	SPRITE_RENDER_H40(245)
+	SPRITE_RENDER_H40(246)
+	case 247:
 		read_map_scroll_a(0, context->vcounter, context);
 		CHECK_LIMIT
-	SPRITE_RENDER_H40(254)
-	case 255:
+	SPRITE_RENDER_H40(248)
+	case 249:
 		render_map_1(context);
 		scan_sprite_table(context->vcounter, context);//Just a guess
 		if (context->flags & FLAG_DMA_RUN) { run_dma_src(context, context->hslot); }
-		context->hslot = 0;
-		context->cycles += slot_cycles;
-		CHECK_ONLY
-	case 0:
+		CHECK_LIMIT
+	case 250:
 		render_map_2(context);
 		scan_sprite_table(context->vcounter, context);//Just a guess
 		CHECK_LIMIT
-	case 1:
+	case 251:
 		read_map_scroll_b(0, context->vcounter, context);
 		CHECK_LIMIT
-	SPRITE_RENDER_H40(2)
-	case 3:
+	SPRITE_RENDER_H40(252)
+	case 253:
 		render_map_3(context);
 		scan_sprite_table(context->vcounter, context);//Just a guess
 		CHECK_LIMIT
-	case 4:
+	case 254:
 		if (context->vcounter == (context->latched_mode & BIT_PAL ? PAL_INACTIVE_START : NTSC_INACTIVE_START)) {
 			context->flags2 |= FLAG2_VINT_PENDING;
 			context->pending_vint_start = context->cycles;
@@ -1214,26 +1172,53 @@
 		context->sprite_draws = MAX_DRAWS;
 		context->flags &= (~FLAG_CAN_MASK & ~FLAG_MASKED);
 		CHECK_LIMIT
-	COLUMN_RENDER_BLOCK(2, 5)
-	COLUMN_RENDER_BLOCK(4, 13)
-	COLUMN_RENDER_BLOCK(6, 21)
-	COLUMN_RENDER_BLOCK_REFRESH(8, 29)
-	COLUMN_RENDER_BLOCK(10, 37)
-	COLUMN_RENDER_BLOCK(12, 45)
-	COLUMN_RENDER_BLOCK(14, 53)
-	COLUMN_RENDER_BLOCK_REFRESH(16, 61)
-	COLUMN_RENDER_BLOCK(18, 69)
-	COLUMN_RENDER_BLOCK(20, 77)
-	COLUMN_RENDER_BLOCK(22, 85)
-	COLUMN_RENDER_BLOCK_REFRESH(24, 93)
-	COLUMN_RENDER_BLOCK(26, 101)
-	COLUMN_RENDER_BLOCK(28, 109)
-	COLUMN_RENDER_BLOCK(30, 117)
-	COLUMN_RENDER_BLOCK_REFRESH(32, 125)
-	COLUMN_RENDER_BLOCK(34, 133)
-	COLUMN_RENDER_BLOCK(36, 141)
-	COLUMN_RENDER_BLOCK(38, 149)
-	COLUMN_RENDER_BLOCK_REFRESH(40, 157)
+	COLUMN_RENDER_BLOCK(2, 255)
+	COLUMN_RENDER_BLOCK(4, 7)
+	COLUMN_RENDER_BLOCK(6, 15)
+	COLUMN_RENDER_BLOCK_REFRESH(8, 23)
+	COLUMN_RENDER_BLOCK(10, 31)
+	COLUMN_RENDER_BLOCK(12, 39)
+	COLUMN_RENDER_BLOCK(14, 47)
+	COLUMN_RENDER_BLOCK_REFRESH(16, 55)
+	COLUMN_RENDER_BLOCK(18, 63)
+	COLUMN_RENDER_BLOCK(20, 71)
+	COLUMN_RENDER_BLOCK(22, 79)
+	COLUMN_RENDER_BLOCK_REFRESH(24, 87)
+	COLUMN_RENDER_BLOCK(26, 95)
+	COLUMN_RENDER_BLOCK(28, 103)
+	COLUMN_RENDER_BLOCK(30, 111)
+	COLUMN_RENDER_BLOCK_REFRESH(32, 119)
+	COLUMN_RENDER_BLOCK(34, 127)
+	COLUMN_RENDER_BLOCK(36, 135)
+	COLUMN_RENDER_BLOCK(38, 143)
+	COLUMN_RENDER_BLOCK_REFRESH(40, 151)
+	case 159:
+		external_slot(context);
+		CHECK_LIMIT
+	case 160:
+		external_slot(context);
+		CHECK_LIMIT
+	//sprite render to line buffer starts
+	case 161:
+		context->cur_slot = MAX_DRAWS-1;
+		memset(context->linebuf, 0, LINEBUF_SIZE);
+		render_sprite_cells(context);
+		CHECK_LIMIT
+	case 162:
+		render_sprite_cells(context);
+		CHECK_LIMIT
+	case 163:
+		render_sprite_cells(context);
+		CHECK_LIMIT
+	case 164:
+		render_sprite_cells(context);
+		vdp_advance_line(context);
+		if (context->vcounter == (context->latched_mode & BIT_PAL ? PAL_INACTIVE_START : NTSC_INACTIVE_START)) {
+			context->hslot++;
+			context->cycles += slot_cycles;
+			return;
+		}
+		CHECK_LIMIT
 	}
 	default:
 		context->hslot++;
@@ -1445,12 +1430,7 @@
 		uint8_t active_slot = context->vcounter < inactive_start || context->vcounter == 0x1FF;
 		uint8_t is_h40 = context->regs[REG_MODE_4] & BIT_H40;
 		if (context->vcounter == inactive_start) {
-			if (is_h40) {
-				//the first inactive line behaves as an active one for the first 4 slots
-				if (context->hslot > LINE_CHANGE_H40 && context->hslot < 171) {
-					active_slot = 1;
-				}
-			} else {
+			if (!is_h40) {
 				//the first inactive line behaves as an active one for the first few slots
 				if (context->hslot > LINE_CHANGE_H32 && context->hslot < 138) {
 					active_slot = 1;
@@ -1465,10 +1445,10 @@
 			}
 		} else {
 			if (is_h40) {
-				if (context->hslot == 167) {
+				if (context->hslot == 161) {
 					context->cur_slot = MAX_DRAWS-1;
 					memset(context->linebuf, 0, LINEBUF_SIZE);
-				} else if (context->hslot == 171) {
+				} else if (context->hslot == 165) {
 					context->sprite_index = 0x80;
 					context->slot_counter = MAX_SPRITES_LINE;
 				}
@@ -1490,7 +1470,9 @@
 			}
 			uint32_t inccycles;
 			if (is_h40) {
-				if (context->hslot < HSYNC_SLOT_H40 || context->hslot >= HSYNC_END_H40) {
+				if (context->hslot == 182) {
+					inccycles = h40_hsync_cycles[0];
+				} else if (context->hslot < HSYNC_SLOT_H40 || context->hslot >= HSYNC_END_H40) {
 					inccycles = MCLKS_SLOT_H40;
 				} else {
 					inccycles = h40_hsync_cycles[context->hslot-HSYNC_SLOT_H40];
diff -r 2be771c4dfbd -r 913a6336ce20 vdp.h
--- a/vdp.h	Tue Jan 26 19:23:10 2016 -0800
+++ b/vdp.h	Thu Jan 28 09:10:14 2016 -0800
@@ -148,9 +148,9 @@
 	uint16_t    vscroll_latch[2];
 	uint32_t    frame;
 	uint16_t    vcounter;
-	uint16_t    hslot; //hcounter/2
 	uint16_t    hscroll_a;
 	uint16_t    hscroll_b;
+	uint8_t     hslot; //hcounter/2
 	uint8_t     latched_mode;
 	uint8_t	    sprite_index;
 	uint8_t     sprite_draws;