From d089f6b64925b806b0a5b1c135cce9a40d412d06 Mon Sep 17 00:00:00 2001
From: Miodrag Milanovic <mmicko@gmail.com>
Date: Thu, 15 Feb 2024 17:52:26 +0100
Subject: [PATCH] z80dma: add PULSE mode handling

---
 src/devices/machine/z80dma.cpp | 21 ++++++++++++++++++++-
 src/devices/machine/z80dma.h   |  1 +
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/devices/machine/z80dma.cpp b/src/devices/machine/z80dma.cpp
index 7bcc98dd520..56dda122074 100644
--- a/src/devices/machine/z80dma.cpp
+++ b/src/devices/machine/z80dma.cpp
@@ -134,7 +134,7 @@ constexpr int TM_SEARCH_TRANSFER    = 0x03;
 #define INT_ON_END_OF_BLOCK     (INTERRUPT_CTRL & 0x02)
 #define INT_ON_READY            (INTERRUPT_CTRL & 0x40)
 #define STATUS_AFFECTS_VECTOR   (INTERRUPT_CTRL & 0x20)
-
+#define PULSE_GENERATED         (INTERRUPT_CTRL & 0x04)
 
 
 //**************************************************************************
@@ -190,6 +190,7 @@ void z80dma_device::device_start()
 	save_item(NAME(m_rdy));
 	save_item(NAME(m_force_ready));
 	save_item(NAME(m_is_read));
+	save_item(NAME(m_is_pulse));
 	save_item(NAME(m_cur_cycle));
 	save_item(NAME(m_latch));
 }
@@ -209,6 +210,7 @@ void z80dma_device::device_reset()
 	m_read_num_follow = m_read_cur_follow = 0;
 	m_reset_pointer = 0;
 	m_is_read = false;
+	m_is_pulse = false;
 	memset(m_regs, 0, sizeof(m_regs));
 	memset(m_regs_follow, 0, sizeof(m_regs_follow));
 
@@ -485,6 +487,23 @@ TIMER_CALLBACK_MEMBER(z80dma_device::timerproc)
 		return;
 	}
 
+	if (PULSE_GENERATED)
+	{
+		if (m_is_pulse)
+		{
+			m_out_int_cb(CLEAR_LINE);
+			m_is_pulse = false;
+		}	
+		else
+		{
+			if ((m_byte_counter & 0xff)==PULSE_CTRL  && is_ready())
+			{
+				m_is_pulse = true;
+				m_out_int_cb(ASSERT_LINE);
+			}
+		}
+	}
+
 	if (m_is_read && !is_ready()) return;
 
 	if (m_is_read)
diff --git a/src/devices/machine/z80dma.h b/src/devices/machine/z80dma.h
index 88b162ed4a2..f327b818223 100644
--- a/src/devices/machine/z80dma.h
+++ b/src/devices/machine/z80dma.h
@@ -125,6 +125,7 @@ private:
 	uint8_t m_reset_pointer;
 
 	bool m_is_read;
+	bool m_is_pulse;
 	uint8_t m_cur_cycle;
 	uint8_t m_latch;