hmcs40: block interrupt after conditional jump

src/devices/cpu/hmcs40/hmcs40.cpp

@@ -10,12 +10,6 @@ References:
 - opcode decoding by Tatsuyuki Satoh, Olivier Galibert, Kevin Horton, Lord Nightmare
   (verified a while later after new documentation was found)
 
-TODO:
-- How the stack works, is probably m_stack_levels+1 program counters, and
-  an index pointing to the current program counter. Then push/pop simply
-  decrements/increments the index. The way it is implemented right now
-  behaves the same.
-
 */
 
 #include "emu.h"
@@ -214,7 +208,6 @@ void hmcs40_cpu_device::device_start()
 
 	// zerofill
 	memset(m_stack, 0, sizeof(m_stack));
-	m_sp = 0;
 	m_op = 0;
 	m_prev_op = 0;
 	m_i = 0;
@@ -244,7 +237,6 @@ void hmcs40_cpu_device::device_start()
 
 	// register for savestates
 	save_item(NAME(m_stack));
-	save_item(NAME(m_sp));
 	save_item(NAME(m_op));
 	save_item(NAME(m_prev_op));
 	save_item(NAME(m_i));
@@ -566,8 +558,8 @@ void hmcs40_cpu_device::execute_run()
 		m_prev_op = m_op;
 		m_prev_pc = m_pc;
 
-		// check/handle interrupt, but not in the middle of a long jump
-		if (m_ie && (m_iri || m_irt) && (m_prev_op & 0x3e0) != 0x340)
+		// check/handle interrupt, but not after LPU/BR/CAL
+		if (m_ie && (m_iri || m_irt) && (m_prev_op & 0x3e0) != 0x340 && (m_prev_op & 0x1c0) != 0x1c0)
 			do_interrupt();
 
 		// fetch next opcode
@@ -575,6 +567,7 @@ void hmcs40_cpu_device::execute_run()
 		m_op = m_program->read_word(m_pc) & 0x3ff;
 		m_i = bitswap<4>(m_op,0,1,2,3); // reversed bit-order for 4-bit immediate param (except for XAMR)
 		increment_pc();
+		cycle();
 
 		// handle opcode
 		switch (m_op)
@@ -805,7 +798,5 @@ void hmcs40_cpu_device::execute_run()
 			default:
 				op_illegal(); break;
 		} /* big switch */
-
-		cycle();
 	}
 }

src/devices/cpu/hmcs40/hmcs40.h

@@ -147,7 +147,6 @@ protected:
 	u16 m_polarity;     // i/o polarity (pmos vs cmos)
 	int m_stack_levels; // number of callstack levels
 	u16 m_stack[4];     // max 4
-	int m_sp;           // internal 'stackpointer'
 	u16 m_op;           // current opcode
 	u16 m_prev_op;
 	u8 m_i;             // 4-bit immediate opcode param
@@ -188,7 +187,6 @@ protected:
 
 	u8 ram_r();
 	void ram_w(u8 data);
-	void exc_stack();
 	void pop_stack();
 	void push_stack();
 

src/devices/cpu/hmcs40/hmcs40op.cpp

@@ -21,26 +21,18 @@ inline void hmcs40_cpu_device::ram_w(u8 data)
 	m_data->write_byte(address, data & 0xf);
 }
 
-void hmcs40_cpu_device::exc_stack()
-{
-	// exchange stack/pc
-	u16 pc = m_stack[m_sp] & m_pcmask;
-	m_stack[m_sp] = m_pc;
-	m_pc = pc;
-}
-
 void hmcs40_cpu_device::pop_stack()
 {
-	if (++m_sp >= m_stack_levels)
-		m_sp = 0;
-	exc_stack();
+	m_pc = m_stack[0] & m_pcmask;
+	for (int i = 0; i < m_stack_levels-1; i++)
+		m_stack[i] = m_stack[i+1];
 }
 
 void hmcs40_cpu_device::push_stack()
 {
-	exc_stack();
-	if (--m_sp < 0)
-		m_sp = m_stack_levels - 1;
+	for (int i = m_stack_levels-1; i >= 1; i--)
+		m_stack[i] = m_stack[i-1];
+	m_stack[0] = m_pc;
 }
 
 
@@ -182,7 +174,7 @@ void hmcs40_cpu_device::op_xsp()
 }
 
 
-// Ram Register Instruction
+// RAM Register Instruction
 
 void hmcs40_cpu_device::op_lam()
 {
@@ -668,6 +660,8 @@ void hmcs40_cpu_device::op_lrb()
 
 void hmcs40_cpu_device::op_p()
 {
+	cycle();
+
 	// P p: Pattern Generation
 	u16 address = m_a | m_b << 4 | m_c << 8 | (m_op & 7) << 9 | (m_pc & ~0x3f);
 	u16 o = m_program->read_word(address & m_prgmask);
@@ -686,6 +680,4 @@ void hmcs40_cpu_device::op_p()
 		write_r(2, o & 0xf);
 		write_r(3, o >> 4 & 0xf);
 	}
-
-	cycle();
 }

src/mame/handheld/hh_hmcs40.cpp

@@ -107,9 +107,6 @@ ROM source notes when dumped from another model, but confident it's the same:
 
 TODO:
 - cgalaxn discrete sound (alien attacking sound effect)
-- gckong glitchy jump on 1st level (rarely happens), caused by MCU stack overflow.
-  It can be tested by jumping up repeatedly at the start position under the ladder,
-  if the glitch happens there, you can jump onto the 2nd floor.
 - epacman2 booting the game in demo mode, pacman should take the shortest route to
   the upper-left power pill: mcu cycle/interrupt timing related
 - kevtris's HMCS40 ROM dumps are incomplete, missing MCU factory test code from
@@ -1420,7 +1417,7 @@ ROM_START( bbtime )
 	ROM_CONTINUE(           0x1e80, 0x0100 )
 
 	ROM_REGION( 461598, "screen", 0)
-	ROM_LOAD( "bbtime.svg", 0, 461598, BAD_DUMP CRC(1fb7b0b8) SHA1(bf938aa1c3c5032daba064a51d5b234bb9e512f5) )
+	ROM_LOAD( "bbtime.svg", 0, 461598, BAD_DUMP CRC(297f30de) SHA1(a5f38cd9c5d5ba9392c5d57ac85ecc2782b6ae7a) )
 ROM_END
 
 
@@ -2730,7 +2727,7 @@ u8 cpacman_state::input_r()
 
 static INPUT_PORTS_START( cpacman )
 	PORT_START("IN.0") // D13 port R0x
-	PORT_CONFNAME( 0x01, 0x01, DEF_STR( Difficulty ) )
+	PORT_CONFNAME( 0x01, 0x00, DEF_STR( Difficulty ) )
 	PORT_CONFSETTING(    0x00, "1" )
 	PORT_CONFSETTING(    0x01, "2" )
 	PORT_BIT( 0x0e, IP_ACTIVE_HIGH, IPT_UNUSED )
@@ -3108,7 +3105,7 @@ static INPUT_PORTS_START( epacman2 )
 
 	PORT_START("IN.3") // D4 port R0x
 	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_UNUSED )
-	PORT_CONFNAME( 0x02, 0x02, DEF_STR( Difficulty ) )
+	PORT_CONFNAME( 0x02, 0x00, DEF_STR( Difficulty ) )
 	PORT_CONFSETTING(    0x00, "1" )
 	PORT_CONFSETTING(    0x02, "2" )
 	PORT_CONFNAME( 0x0c, 0x04, DEF_STR( Players ) )
@@ -3282,7 +3279,7 @@ ROM_END
 
   Entex Turtles (manufactured in Japan)
   * PCB label: 560359
-  * Hitachi QFP HD38820A43 MCU
+  * Hitachi QFP HD38820A43 MCU, speed adjustable by knob
   * COP411L sub MCU for sound, label COP411L-KED/N
   * cyan/red/green VFD NEC FIP15BM32T
 
@@ -3484,11 +3481,13 @@ ROM_END
 
   Entex Stargate (manufactured in Japan)
   * PCB label: 5603521/31
-  * Hitachi QFP HD38820A42 MCU
+  * Hitachi QFP HD38820A42 MCU, speed adjustable by knob
   * COP411L sub MCU for sound, label ~/B8236 COP411L-KEC/N, volume control
   * cyan/red/green VFD NEC FIP15AM32T (EL628-003) no. 2-421
   * color overlay: bottom row: red
 
+  BTANB: when changing direction, player bullets remain and become obstacles
+
 ***************************************************************************/
 
 class estargte_state : public eturtles_state
@@ -3549,11 +3548,11 @@ static INPUT_PORTS_START( estargte )
 	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_UNUSED )
 
 	PORT_START("IN.4") // D5 INT0/1
-	PORT_CONFNAME( 0x01, 0x00, DEF_STR( Players ) ) PORT_CHANGED_MEMBER(DEVICE_SELF, eturtles_state, input_changed, 0)
-	PORT_CONFSETTING(    0x00, "0 (Demo)" ) // yes, same value as 1-player, hold the Inviso button at boot to enter demo mode
+	PORT_CONFNAME( 0x11, 0x00, DEF_STR( Players ) ) PORT_CHANGED_MEMBER(DEVICE_SELF, eturtles_state, input_changed, 0)
+	PORT_CONFSETTING(    0x10, "0 (Demo)" ) // yes, same value as 1-player, hold the Inviso button at boot to enter demo mode
 	PORT_CONFSETTING(    0x00, "1" )
 	PORT_CONFSETTING(    0x01, "2" )
-	PORT_CONFNAME( 0x02, 0x02, DEF_STR( Difficulty ) ) PORT_CHANGED_MEMBER(DEVICE_SELF, eturtles_state, input_changed, 0)
+	PORT_CONFNAME( 0x02, 0x00, DEF_STR( Difficulty ) ) PORT_CHANGED_MEMBER(DEVICE_SELF, eturtles_state, input_changed, 0)
 	PORT_CONFSETTING(    0x00, "1" )
 	PORT_CONFSETTING(    0x02, "2" )
 

src/mame/handheld/hh_ucom4.cpp

@@ -1050,7 +1050,7 @@ ROM_START( bcclimbr )
 	ROM_LOAD( "d553c-170", 0x0000, 0x0800, CRC(fc2eabdb) SHA1(0f5cc854be7fdf105d9bd2114659d40c65f9d782) )
 
 	ROM_REGION( 219983, "screen", 0)
-	ROM_LOAD( "bcclimbr.svg", 0, 219983, CRC(02994933) SHA1(e1b650a70c6010cb78c84088e1bde2413682823b) )
+	ROM_LOAD( "bcclimbr.svg", 0, 219983, CRC(92c83961) SHA1(208b4c63c6aecd90acb15d9767fa1cf3aed835fb) )
 ROM_END