amiga/agnus_copper: delay MOVE writes regardless of what register it triggers

Author: angelosa

hash/amigaocs_flop.xml

@@ -49337,7 +49337,7 @@ ATK test: OK
 		<publisher>Team 17</publisher>
 		<notes><![CDATA[
 Red screen [FDC] dsksync (fixed?)
-a500: no main sprite (works with a500p, a1200)
+Main sprite randomly don't show up, [Copper]?
 [Copper] cuts bottom part of screen badly during gameplay, may use SKIP
 ATK test: failed
 ]]></notes>

src/mame/amiga/agnus_copper.cpp

@@ -309,22 +309,14 @@ int agnus_copper_device::execute_next(int xpos, int ypos, bool is_blitter_busy,
 		word0 = (word0 >> 1) & 0xff;
 		if (word0 >= m_cdang_setting)
 		{
-			if (delay[word0] == 0)
-			{
-				//LOGCHIPSET("%02X.%02X: Write to %s = %04x\n", ypos, xpos / 2, s_custom_reg_names[word0 & 0xff], word1);
-				LOGCHIPSET("%02X.%02X: MOVE $dff%03x = %04x\n",
-					ypos,
-					xpos / 2,
-					word0 << 1,
-					word1
-				);
-				m_host_space->write_word(0xdff000 | (word0 << 1), word1);
-			}
-			else    // additional 2 cycles needed for non-Agnus registers
-			{
-				m_pending_offset = word0;
-				m_pending_data = word1;
-			}
+			// delay write to the next available DMA slot if not in blanking area
+			// - bchvolly (title), suprfrog & abreed (bottom playfield rows)
+			const bool horizontal_blank = xpos < 0x47;
+			const int move_offset = horizontal_blank ? 0 : std::max(num_planes - 4, 0);
+
+			m_pending_offset = word0;
+			m_pending_data = word1;
+			xpos += COPPER_CYCLES_TO_PIXELS(move_offset);
 		}
 
 		/* illegal writes suspend until next frame */
@@ -351,7 +343,8 @@ int agnus_copper_device::execute_next(int xpos, int ypos, bool is_blitter_busy,
 		/* handle a wait */
 		if ((word1 & 1) == 0)
 		{
-			const int wait_offset = std::max(num_planes - 4, 0) + 1;
+			const bool horizontal_blank = xpos < 0x47;
+			const int wait_offset = horizontal_blank ? 0 : std::max(num_planes - 4, 0) + 1;
 
 			LOGINST("  WAIT %04x & %04x (currently %04x, num planes %d +%d)\n",
 				m_waitval,
@@ -383,6 +376,8 @@ int agnus_copper_device::execute_next(int xpos, int ypos, bool is_blitter_busy,
 				LOGINST("  Skipped\n");
 
 				/* count the cycles it out have taken to fetch the next instruction */
+				// TODO: look ahead, check if next instruction is a valid MOVE
+				// SKIP/WAIT and illegal instructions aren't skipped.
 				m_pc += 4;
 				xpos += COPPER_CYCLES_TO_PIXELS(2);
 			}

src/mame/amiga/agnus_copper.h

@@ -68,30 +68,6 @@ class agnus_copper_device : public device_t
 	u16 m_waitmask;
 	u16 m_pending_offset;
 	u16 m_pending_data;
-
-	// waitstate delays for copper
-	// basically anything that doesn't belong to Angus has a penalty for Copper
-	static constexpr u16 delay[256] =
-	{
-		1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,1,1,1,1,0,0,0,0,0,0,0,0,    /* 0x000 - 0x03e */
-		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,                        /* 0x040 - 0x05e */
-		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,                        /* 0x060 - 0x07e */
-		0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,                        /* 0x080 - 0x09e */
-		1,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,    /* 0x0a0 - 0x0de */
-		/* BPLxPTH/BPLxPTL */
-		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,                        /* 0x0e0 - 0x0fe */
-		/* BPLCON0-3,BPLMOD1-2 */
-		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,                        /* 0x100 - 0x11e */
-		/* SPRxPTH/SPRxPTL */
-		1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,                        /* 0x120 - 0x13e */
-		/* SPRxPOS/SPRxCTL/SPRxDATA/SPRxDATB */
-		1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,    /* 0x140 - 0x17e */
-		/* COLORxx */
-		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,    /* 0x180 - 0x1be */
-		/* RESERVED */
-		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 /* 0x1c0 - 0x1fe */
-	};
-
 };
 
 

src/mame/amiga/amiga_m.cpp

@@ -1700,6 +1700,9 @@ void amiga_state::custom_chip_w(offs_t offset, uint16_t data)
 			{
 				CUSTOM_REG(REG_BEAMCON0) = data;
 				update_screenmode();
+				// TODO: variable beam counter, disables hard display stops, enables HTOTAL/VTOTAL programming
+				if (BIT(data, 7))
+					popmessage("BEAMCON0: VARBEAMEN enabled");
 			}
 			break;
 

src/mame/amiga/amigaaga.cpp

@@ -623,10 +623,13 @@ void amiga_state::aga_render_scanline(bitmap_rgb32 &bitmap, int scanline)
 
 		if ((raw_scanline & 1) == 0)
 		{
+   			const int min_x = 0x18 << 1;
+			const int max_x = 0x34 << 1;
+
 			// TODO: refine, merge with OCS version
-			if (x >= 0x18 && x <= 0x34 && (x & 3) == 0)
+			if (x >= min_x && x <= max_x && (x & 7) == 0)
 			{
-				int num = (x - 0x18) >> 2;
+				int num = (x - min_x) >> 3;
 				//printf("%d %02x\n", num, x);
 				aga_update_sprite_dma(raw_scanline >> 1, num);
 			}