# HG changeset patch
# User Michael Pavone <pavone@retrodev.com>
# Date 1708804424 28800
# Node ID b0408f38f46461efe32c4766e7213e7ae9a5ad3d
# Parent  f9d5c137c74b93f89bc34d6278c97a9ca7100056
Add missing mask to vscroll calculation in Mode 4

diff -r f9d5c137c74b -r b0408f38f464 vdp.c
--- a/vdp.c	Fri Feb 23 23:09:20 2024 -0800
+++ b/vdp.c	Sat Feb 24 11:53:44 2024 -0800
@@ -1371,8 +1371,10 @@
 	uint32_t vscroll = line;
 	if (column < 24 || !(context->regs[REG_MODE_1] & BIT_VSCRL_LOCK)) {
 		vscroll += context->regs[REG_Y_SCROLL];
+		vscroll &= 511;
 	}
 	if (vscroll > 223) {
+		//TODO: support V28 and V30 for SMS2/GG VDPs
 		vscroll -= 224;
 	}
 	address += (vscroll >> 3) * 2 * 32;