Clear the low 2 bits of CD when a register is written to

1 files changed, 1 insertions, 0 deletions

diff --git a/vdp.c b/vdp.c
index f1f28fc..efe7dac 100644
--- a/vdp.c
+++ b/vdp.c
@@ -1489,6 +1489,7 @@ int vdp_control_port_write(vdp_context * context, uint16_t value)
 						context->framebuf = context->oddbuf;
 					}
 				}
+				context->cd &= 0x3C;
 			}
 		} else {
 			context->flags |= FLAG_PENDING;