# HG changeset patch
# User Michael Pavone <pavone@retrodev.com>
# Date 1453864990 28800
# Node ID 2be771c4dfbdd9834b5d4ddf9adce2e8febe65e4
# Parent  e64168bb2b25dbc0ad93144eec6937cd750f5fe0
After reviewing the results of my test ROM again it seems pretty clear that the VBlank flag gets set at the same time as the vcounter changes

diff -r e64168bb2b25 -r 2be771c4dfbd vdp.c
--- a/vdp.c	Sun Jan 17 14:46:12 2016 -0800
+++ b/vdp.c	Tue Jan 26 19:23:10 2016 -0800
@@ -1692,22 +1692,7 @@
 	uint32_t line= context->vcounter;
 	uint32_t slot = context->hslot;
 	uint32_t inactive_start = (context->latched_mode & BIT_PAL ? PAL_INACTIVE_START : NTSC_INACTIVE_START);
-	if (
-		(
-			line > inactive_start
-			&& line < 0x1FF
-		)
-		|| (line == inactive_start
-			&& (
-				slot >= (context->regs[REG_MODE_4] & BIT_H40 ? VBLANK_START_H40 : VBLANK_START_H32)
-				|| slot < (context->regs[REG_MODE_4] & BIT_H40 ? LINE_CHANGE_H40 : LINE_CHANGE_H32)
-			)
-		)
-		|| (line == 0x1FF
-			&& slot < (context->regs[REG_MODE_4] & BIT_H40 ? VBLANK_START_H40 : VBLANK_START_H32))
-			&& slot >= (context->regs[REG_MODE_4] & BIT_H40 ? LINE_CHANGE_H40 : LINE_CHANGE_H32)
-		|| !(context->regs[REG_MODE_2] & BIT_DISP_EN)
-	) {
+	if ((line >= inactive_start && line < 0x1FF) || !(context->regs[REG_MODE_2] & BIT_DISP_EN)) {
 		value |= 0x8;
 	}
 	if (context->regs[REG_MODE_4] & BIT_H40) {