fix http://mametesters.org/view.php?id=5350

to quote OG:
"CPU cores *must* call standard_irq_callback() when taking an
interrupt.  No ifs, no buts,  Not only HOLD_LINE relies on it, but
more importantly run until interrupt relies on it."

src/emu/cpu/m6809/base6x09.ops

@@ -7,6 +7,7 @@ NMI:
 	m_cc |= CC_I | CC_F;
 	set_ea(VECTOR_NMI);
 	eat(1);
+	standard_irq_callback(INPUT_LINE_NMI);
 	goto INTERRUPT_VECTOR;
 
 FIRQ:
@@ -25,6 +26,7 @@ FIRQ:
 	m_cc |= CC_I | CC_F;
 	set_ea(VECTOR_FIRQ);
 	eat(1);
+	standard_irq_callback(M6809_FIRQ_LINE);
 	goto INTERRUPT_VECTOR;
 
 IRQ:
@@ -35,6 +37,7 @@ IRQ:
 	m_cc |= CC_I;
 	set_ea(VECTOR_IRQ);
 	eat(1);
+	standard_irq_callback(M6809_IRQ_LINE);
 	goto INTERRUPT_VECTOR;
 
 INTERRUPT_VECTOR:
@@ -447,6 +450,16 @@ CWAI:
 
 	set_ea(m_ea.w);	// need to do this to set the addressing mode
 	m_cc |= CC_I | (m_ea.w != VECTOR_IRQ ? CC_F : 0);
+
+	// invoke standard interrupt callback for MAME core
+	switch (m_ea.w)
+	{
+		case VECTOR_NMI:	standard_irq_callback(INPUT_LINE_NMI); break;
+		case VECTOR_FIRQ:	standard_irq_callback(M6809_FIRQ_LINE); break;
+		case VECTOR_IRQ:	standard_irq_callback(M6809_IRQ_LINE); break;
+		default:			break;
+	}
+
 	goto INTERRUPT_VECTOR;
 
 LEA_xy:

src/emu/cpu/m6809/hd6309.h

@@ -140,7 +140,7 @@ enum
 	HD6309_ZERO_WORD
 };
 
-#define HD6309_IRQ_LINE  0   /* IRQ line number */
-#define HD6309_FIRQ_LINE 1   /* FIRQ line number */
+#define HD6309_IRQ_LINE  M6809_IRQ_LINE   /* 0 - IRQ line number */
+#define HD6309_FIRQ_LINE M6809_FIRQ_LINE  /* 1 - FIRQ line number */
 
 #endif // __HD6309_H__

src/emu/cpu/m6809/hd6309.ops

@@ -1,6 +1,6 @@
 MAIN:
 	// check interrupt lines
-	switch(check_pending_interrupt())
+	switch(get_pending_interrupt())
 	{
 		case VECTOR_NMI:	goto NMI;
 		case VECTOR_FIRQ:	goto FIRQ;

src/emu/cpu/m6809/konami.h

@@ -73,7 +73,7 @@ private:
 	void execute_one();
 };
 
-#define KONAMI_IRQ_LINE 0   /* IRQ line number */
-#define KONAMI_FIRQ_LINE 1   /* FIRQ line number */
+#define KONAMI_IRQ_LINE  M6809_IRQ_LINE   /* 0 - IRQ line number */
+#define KONAMI_FIRQ_LINE M6809_FIRQ_LINE  /* 1 - FIRQ line number */
 
 #endif /* __KONAMI_CPU_H__ */

src/emu/cpu/m6809/konami.ops

@@ -1,6 +1,6 @@
 MAIN:
 	// check interrupt lines
-	switch(check_pending_interrupt())
+	switch(get_pending_interrupt())
 	{
 		case VECTOR_NMI:	goto NMI;
 		case VECTOR_FIRQ:	goto FIRQ;

src/emu/cpu/m6809/m6809.h

@@ -238,7 +238,6 @@ protected:
 	bool is_register_addressing_mode();
 	bool is_ea_addressing_mode() { return m_addressing_mode == ADDRESSING_MODE_EA; }
 	UINT16 get_pending_interrupt();
-	UINT16 check_pending_interrupt();
 	void log_illegal();
 
 private:

src/emu/cpu/m6809/m6809.ops

@@ -1,6 +1,6 @@
 MAIN:
 	// check interrupt lines
-	switch(check_pending_interrupt())
+	switch(get_pending_interrupt())
 	{
 		case VECTOR_NMI:	goto NMI;
 		case VECTOR_FIRQ:	goto FIRQ;

src/emu/cpu/m6809/m6809inl.h

@@ -302,43 +302,12 @@ inline bool m6809_base_device::is_register_addressing_mode()
 
 inline UINT16 m6809_base_device::get_pending_interrupt()
 {
-	UINT16 result;
 	if (m_nmi_asserted)
-		result = VECTOR_NMI;
+		return VECTOR_NMI;
 	else if (!(m_cc & CC_F) && m_firq_line)
-		result = VECTOR_FIRQ;
+		return VECTOR_FIRQ;
 	else if (!(m_cc & CC_I) && m_irq_line)
-		result = VECTOR_IRQ;
+		return VECTOR_IRQ;
 	else
-		result = 0;
-	return result;
-}
-
-
-
-//-------------------------------------------------
-//  check_pending_interrupt
-//-------------------------------------------------
-
-inline UINT16 m6809_base_device::check_pending_interrupt()
-{
-	UINT16 result = get_pending_interrupt();
-
-	// check_pending_interrupt() will also invoke the IRQ
-	// callback for FIRQ and IRQ interrupts
-	//
-	// I'm not sure why this is necessary; neither the 6809, 6309
-	// nor (presumably) Konami had any interrupt acknowledge lines so
-	// it isn't clear what this is reflecting
-	switch(result)
-	{
-		case VECTOR_FIRQ:
-			standard_irq_callback(M6809_FIRQ_LINE);
-			break;
-		case VECTOR_IRQ:
-			standard_irq_callback(M6809_IRQ_LINE);
-			break;
-	}
-
-	return result;
+		return 0;
 }