From c929d074dc888a737b40581ca01a0eb8fb5b895d Mon Sep 17 00:00:00 2001
From: MooglyGuy <therealmogminer@gmail.com>
Date: Mon, 14 Jan 2019 23:36:20 +0100
Subject: [PATCH] spg2xx: Only flag sprite DMA done IRQ if it is enabled. Gets
 mattelcs to boot. nw

---
 src/devices/machine/spg2xx.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/devices/machine/spg2xx.cpp b/src/devices/machine/spg2xx.cpp
index 755c9bc9120..c9eba98f2cb 100644
--- a/src/devices/machine/spg2xx.cpp
+++ b/src/devices/machine/spg2xx.cpp
@@ -688,7 +688,14 @@ void spg2xx_device::do_sprite_dma(uint32_t len)
 	}
 
 	m_video_regs[0x72] = 0;
-	VIDEO_IRQ_STATUS |= 4;
+	if (VIDEO_IRQ_ENABLE & 4)
+	{
+		const uint16_t old = VIDEO_IRQ_STATUS;
+		VIDEO_IRQ_STATUS |= 4;
+		const uint16_t changed = old ^ (VIDEO_IRQ_ENABLE & VIDEO_IRQ_STATUS);
+		if (changed)
+			check_video_irq();
+	}
 }
 
 READ16_MEMBER(spg2xx_device::video_r)