b5000: remove tkbs_step

src/devices/cpu/b5000/b5000.cpp

@@ -63,7 +63,7 @@ u16 b5000_cpu_device::decode_digit(u8 data)
 		0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f,
 
 		// ?, ?, ?, ?, ?, ?
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+		0, 0, 0, 0, 0, 0
 	};
 	return lut_segs[data & 0xf];
 }
@@ -120,7 +120,7 @@ void b5000_cpu_device::execute_one()
 		case 0x00: op_nop(); break;
 		case 0x01: op_tc(); break;
 		case 0x02: op_tkb(); break;
-		case 0x03: m_tkbs_step = 1; break;
+		case 0x03: op_tkbs(); break;
 		case 0x39: op_rsc(); break;
 		case 0x3b: op_sc(); break;
 		case 0x74: op_kseg(); break;

src/devices/cpu/b5000/b5000.h

@@ -100,7 +100,7 @@ protected:
 	virtual void op_kseg();
 	virtual void op_atbz() override;
 	virtual void op_tkb();
-	virtual void op_tkbs() override;
+	virtual void op_tkbs();
 	virtual void op_read();
 	virtual void op_tdin();
 };

src/devices/cpu/b5000/b5000base.cpp

@@ -73,13 +73,11 @@ void b5000_base_device::device_start()
 	m_c = 0;
 	m_prev_c = 0;
 	m_prev2_c = 0;
-	m_prev3_c = 0;
 	m_sr = false;
 	m_skip = false;
 	m_seg = 0;
 
 	m_atbz_step = 0;
-	m_tkbs_step = 0;
 	m_tra_step = 0;
 	m_ret_step = 0;
 
@@ -101,13 +99,11 @@ void b5000_base_device::device_start()
 	save_item(NAME(m_c));
 	save_item(NAME(m_prev_c));
 	save_item(NAME(m_prev2_c));
-	save_item(NAME(m_prev3_c));
 	save_item(NAME(m_sr));
 	save_item(NAME(m_skip));
 	save_item(NAME(m_seg));
 
 	save_item(NAME(m_atbz_step));
-	save_item(NAME(m_tkbs_step));
 	save_item(NAME(m_tra_step));
 	save_item(NAME(m_ret_step));
 
@@ -152,7 +148,6 @@ void b5000_base_device::device_reset()
 	m_skip = false;
 
 	m_atbz_step = 0;
-	m_tkbs_step = 0;
 	m_tra_step = 0;
 	m_ret_step = 0;
 }
@@ -180,7 +175,6 @@ void b5000_base_device::execute_run()
 
 		m_prev_bl = m_bl;
 		m_prev_bu = m_bu;
-		m_prev3_c = m_prev2_c;
 		m_prev2_c = m_prev_c;
 		m_prev_c = m_c;
 
@@ -203,7 +197,6 @@ void b5000_base_device::execute_run()
 		// some opcodes have multiple steps and will run in parallel with next ones,
 		// eg. it may fetch in order A,B and parts executed in order B,A
 		if (m_atbz_step) op_atbz();
-		if (m_tkbs_step) op_tkbs();
 		if (m_tra_step) op_tra();
 		if (m_ret_step) op_ret();
 

src/devices/cpu/b5000/b5000base.h

@@ -89,18 +89,15 @@ protected:
 	u8 m_c;
 	u8 m_prev_c;
 	u8 m_prev2_c;
-	u8 m_prev3_c;
 	bool m_sr;
 	bool m_skip;
 	u16 m_seg;
 
 	u8 m_atbz_step;
-	u8 m_tkbs_step;
 	u8 m_tra_step;
 	u8 m_ret_step;
 
 	virtual void op_atbz() { ; }
-	virtual void op_tkbs() { ; }
 	virtual void op_tra() { ; }
 	virtual void op_ret() { ; }
 

src/devices/cpu/b5000/b5000op.cpp

@@ -281,13 +281,13 @@ void b5000_cpu_device::op_atbz()
 			op_kseg();
 			break;
 
-		// step 2: disable strobe
-		case 2:
+		// step 3: disable strobe
+		case 3:
 			m_write_str(0);
 			break;
 
-		// step 3: load strobe from Bl
-		case 3:
+		// step 4: load strobe from Bl
+		case 4:
 			m_write_str(1 << (m_ram_addr & 0xf));
 			m_atbz_step = 0;
 			return;
@@ -306,27 +306,11 @@ void b5000_cpu_device::op_tkb()
 
 void b5000_cpu_device::op_tkbs()
 {
-	assert(m_tkbs_step > 0);
+	// TKBS: TKB + load segments
+	op_tkb();
 
-	// TKBS: TKB + load segments (multi step)
-	switch (m_tkbs_step)
-	{
-		// step 1: TKB
-		case 1:
-			op_tkb();
-			break;
-
-		// step 2: load segments from RAM
-		case 2:
-			// note: SEG0(DP) from C flag is delayed 2 cycles
-			seg_w(m_seg | decode_digit(ram_r()) << 1 | m_prev3_c);
-			m_tkbs_step = 0;
-			return;
-
-		default:
-			break;
-	}
-	m_tkbs_step++;
+	// note: SEG0(DP) from C flag is delayed 2 cycles
+	seg_w(m_seg | decode_digit(ram_r()) << 1 | m_prev2_c);
 }
 
 void b5000_cpu_device::op_read()

src/devices/cpu/b5000/b6000.cpp

@@ -102,7 +102,7 @@ void b6000_cpu_device::op_tkbs()
 
 void b6000_cpu_device::op_atbz()
 {
-	// ATBZ: load strobe from A (no ATB step)
-	m_write_str(1 << (m_a & 0xf));
+	// ATBZ: KSEG + load strobe (no ATB step)
 	op_kseg();
+	m_write_str(1 << m_a);
 }

src/devices/cpu/b5000/b6100.cpp

@@ -2,7 +2,7 @@
 // copyright-holders:hap
 /*
 
-  Rockwell B6100 MCU (based on A5500+B6000)
+  Rockwell B6100 MCU (based on B5500+B6000)
 
 */