From 508a9aedf03d887dcc00a8c53caf8cef1ada2937 Mon Sep 17 00:00:00 2001
From: Michael Pavone <pavone@retrodev.com>
Date: Sun, 24 Apr 2016 02:19:48 -0700
Subject: Half assed, prefetch based open bus value emulation. Gets BlastEm up
 to 119/122 in VDP FIFO Testing

---
 vdp.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'vdp.c')

diff --git a/vdp.c b/vdp.c
index 8b1ed22..5e1fab8 100644
--- a/vdp.c
+++ b/vdp.c
@@ -1694,9 +1694,8 @@ void vdp_test_port_write(vdp_context * context, uint16_t value)
 uint16_t vdp_control_port_read(vdp_context * context)
 {
 	context->flags &= ~FLAG_PENDING;
-	//TODO: Open bus emulation
 	//Bits 15-10 are not fixed like Charles MacDonald's doc suggests, but instead open bus values that reflect 68K prefetch
-	uint16_t value = 0;
+	uint16_t value = get_open_bus_value() & 0xFC00;
 	if (context->fifo_read < 0) {
 		value |= 0x200;
 	}
-- 
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