riscii: Add interrupt processing (nw)

src/devices/cpu/rii/riscii.cpp

@@ -1826,6 +1826,43 @@ void riscii_series_device::execute_tbrd(u32 ptr)
 		m_exec_state = EXEC_CYCLE1;
 }
 
+bool riscii_series_device::interrupt_active() const
+{
+	if (!BIT(m_cpucon, 2))
+		return false;
+	else
+		return (m_intcon & m_intsta) != 0
+			|| (m_painten & m_paintsta) != 0
+			|| (m_spista & 0x30) == 0x30
+			|| (m_sphtcon & 0x30) == 0x30;
+}
+
+u32 riscii_series_device::vector_interrupt() const
+{
+	// Input port A
+	if ((m_painten & m_paintsta) != 0)
+		return 0x00002;
+
+	// Capture
+	if ((m_intcon & m_intsta & 0x80) != 0)
+		return 0x00004;
+
+	// Speech timer
+	if ((m_sphtcon & 0x30) == 0x30)
+		return 0x00006;
+
+	// Timers 0–2
+	if ((m_intcon & m_intsta & 0x07) != 0)
+		return 0x00008;
+
+	// Peripheral
+	if ((m_intcon & m_intsta & 0x78) != 0 || (m_spista & 0x30) == 0x30)
+		return 0x0000a;
+
+	// Should not reach here
+	return 0x00000;
+}
+
 void riscii_series_device::execute_run()
 {
 	while (m_icount > 0)
@@ -1844,6 +1881,12 @@ void riscii_series_device::execute_run()
 					m_pc = m_ppc;
 				}
 			}
+			else if (interrupt_active())
+			{
+				// Disable interrupts and call handler
+				m_cpucon &= 0xfb;
+				execute_call(vector_interrupt());
+			}
 			else
 				execute_cycle1(fetch_program_word());
 			break;

src/devices/cpu/rii/riscii.h

@@ -263,6 +263,10 @@ private:
 	void execute_cycle1(u16 opcode);
 	void execute_tbrd(u32 ptr);
 
+	// interrupt helpers
+	bool interrupt_active() const;
+	u32 vector_interrupt() const;
+
 	enum exec_state : u8 {
 		EXEC_CYCLE1,
 		EXEC_ADCPCM, EXEC_SBCPCM,