Initial implementation of sprite overflow and sprite collision status register flags

2 files changed, 18 insertions, 4 deletions

diff --git a/vdp.c b/vdp.c
index c1e04f0..26fbb32 100644
--- a/vdp.c
+++ b/vdp.c
@@ -156,10 +156,16 @@ void render_sprite_cells(vdp_context * context)
 		context->cur_slot--;
 		for (uint16_t address = d->address; address != ((d->address+4) & 0xFFFF); address++) {
 			if (x >= 0 && x < 320 && !(context->linebuf[x] & 0xF)) {
+				if (context->linebuf[x] && (context->vdpmem[address] >> 4)) {
+					context->flags2 |= FLAG2_SPRITE_COLLIDE;
+				}
 				context->linebuf[x] = (context->vdpmem[address] >> 4) | d->pal_priority;
 			}
 			x += dir;
 			if (x >= 0 && x < 320 && !(context->linebuf[x] & 0xF)) {
+				if (context->linebuf[x] && (context->vdpmem[address] & 0xF)) {
+					context->flags2 |= FLAG2_SPRITE_COLLIDE;
+				}
 				context->linebuf[x] = (context->vdpmem[address] & 0xF)  | d->pal_priority;
 			}
 			x += dir;
@@ -1539,6 +1545,14 @@ uint16_t vdp_control_port_read(vdp_context * context)
 	if (context->flags2 & FLAG2_VINT_PENDING) {
 		value |= 0x80;
 	}
+	if (context->flags & FLAG_DOT_OFLOW) {
+		value |= 0x40;
+	}
+	if (context->flags2 & FLAG2_SPRITE_COLLIDE) {
+		value |= 0x20;
+		//TODO: Test when this is actually cleared
+		context->flags2 &= ~FLAG2_SPRITE_COLLIDE;
+	}
 	if ((context->regs[REG_MODE_4] & BIT_INTERLACE) && context->framebuf == context->oddbuf) {
 		value |= 0x10;
 	}
@@ -1557,7 +1571,6 @@ uint16_t vdp_control_port_read(vdp_context * context)
 		value |= 0x1;
 	}
 	//printf("status read at cycle %d returned %X\n", context->cycles, value);
-	//TODO: Sprite overflow, sprite collision, odd frame flag
 	return value;
 }
 
diff --git a/vdp.h b/vdp.h
index 9b99b97..830aa5a 100644
--- a/vdp.h
+++ b/vdp.h
@@ -45,9 +45,10 @@
 #define FLAG_DMA_RUN       0x40
 #define FLAG_DMA_PROG      0x80
 
-#define FLAG2_VINT_PENDING 0x01
-#define FLAG2_HINT_PENDING 0x02
-#define FLAG2_READ_PENDING 0x04
+#define FLAG2_VINT_PENDING   0x01
+#define FLAG2_HINT_PENDING   0x02
+#define FLAG2_READ_PENDING   0x04
+#define FLAG2_SPRITE_COLLIDE 0x08
 
 #define DISPLAY_ENABLE 0x40