cpu/z80: Improved z80 code generation

before: ~/workspace/mame (z80-perf*) » ./mame pacman -bench 300
Average speed: 11871.24% (299 seconds)

after: ~/workspace/mame (z80-perf*) » ./mame pacman -bench 300
Average speed: 12235.35% (299 seconds)

src/devices/cpu/z80/nsc800.cpp

@@ -47,8 +47,7 @@ void nsc800_device::device_reset()
 //-------------------------------------------------
 //  execute
 //-------------------------------------------------
-
+void nsc800_device::execute_run()
-void nsc800_device::do_op()
 {
 	#include "cpu/z80/ncs800.hxx"
 }

src/devices/cpu/z80/nsc800.h

@@ -26,9 +26,9 @@ protected:
 	virtual void device_reset() override ATTR_COLD;
 
 	// device_execute_interface implementation
+	virtual void execute_run() override;
 	virtual void execute_set_input(int inputnum, int state) override;
 
-	virtual void do_op() override;
 	u8 m_nsc800_irq_state[3]; // state of NSC800 restart interrupts A, B, C
 };
 

src/devices/cpu/z80/r800.cpp

@@ -97,7 +97,7 @@ void r800_device::muluw(u16 value)
 	set_f((F & (HF|NF)) | z | c);
 }
 
-void r800_device::do_op()
+void r800_device::execute_run()
 {
 	#include "cpu/z80/r800.hxx"
 }

src/devices/cpu/z80/r800.h

@@ -33,6 +33,7 @@ protected:
 	// device_execute_interface overrides
 	virtual u64 execute_clocks_to_cycles(u64 clocks) const noexcept override { return (clocks + 4 - 1) / 4; }
 	virtual u64 execute_cycles_to_clocks(u64 cycles) const noexcept override { return (cycles * 4); }
+	virtual void execute_run() override;
 
 	// device_disasm_interface implementation
 	virtual std::unique_ptr<util::disasm_interface> create_disassembler() override;
@@ -40,8 +41,6 @@ protected:
 	u8 r800_sll(u8 value);
 	void mulub(u8 value);
 	void muluw(u16 value);
-
-	virtual void do_op() override;
 };
 
 // device type declaration

src/devices/cpu/z80/z80.cpp

@@ -699,26 +699,12 @@ void z80_device::device_reset()
 	m_iff2 = 0;
 }
 
-void z80_device::do_op()
-{
-	#include "cpu/z80/z80.hxx"
-}
-
 /****************************************************************************
  * Execute 'cycles' T-states.
  ****************************************************************************/
 void z80_device::execute_run()
 {
-	if (m_wait_state)
+	#include "cpu/z80/z80.hxx"
-	{
-		m_icount = 0; // stalled
-		return;
-	}
-
-	while (m_icount > 0)
-	{
-		do_op();
-	}
 }
 
 void z80_device::execute_set_input(int inputnum, int state)

src/devices/cpu/z80/z80.h

@@ -121,8 +121,6 @@ protected:
 	void set_f(u8 f);
 	void block_io_interrupted_flags();
 
-	virtual void do_op();
-
 	virtual u8 data_read(u16 addr);
 	virtual void data_write(u16 addr, u8 value);
 	virtual u8 stack_read(u16 addr) { return data_read(addr); }

src/devices/cpu/z80/z80.lst

@@ -508,11 +508,11 @@ macro   r800:otdr
 
 macro   jump	%opcode
 	m_ref = 0x%opcode00;
-	if (true) return;
+	goto start;
 
 macro   jump_prefixed   %prefix
 	m_ref = (%prefix << 16) | (TDAT8 << 8);
-	if (true) return;
+	goto start;
 
 macro   take_nmi
 	// Check if processor was halted
@@ -671,6 +671,9 @@ macro   ncs800:check_interrupts
 # ROP
 ##########################################################
 ffff
+	rop:
+	m_ref = 0xffff00;
+	if (m_icount <= 0) return;
 	if (m_busrq_state) {
 		if (!m_busack_state) {
 			m_busack_state = 1;
@@ -691,13 +694,13 @@ ffff
 		call rop
 		PC--;
 		m_ref = 0xffff00;
-		return;
+		goto rop;
 	} else {
 		PRVPC = PC;
 		debugger_instruction_hook(PC);
 		call rop
 		m_ref = (0x00 << 16) | (TDAT8 << 8);
-		return;
+		goto start;
 	}
 
 

src/devices/cpu/z80/z80make.py

@@ -220,6 +220,13 @@ class OpcodeList:
 
     def save_exec(self, f):
         prefix = None
+        print("if (m_wait_state)", file=f)
+        print("{", file=f)
+        print("	m_icount = 0; // stalled", file=f)
+        print("	return;", file=f)
+        print("}", file=f)
+        print("while (true) {", file=f)
+        print("start:", file=f)
         print("switch (u8(m_ref >> 16)) // prefix", file=f)
         print("{", file=f)
         for opc in self.opcode_info:
@@ -237,10 +244,8 @@ class OpcodeList:
                 print("\tswitch (u8(m_ref >> 8)) // opcode", file=f)
                 print("\t{", file=f)
             print("\tcase 0x%s:" % (opc.code[2:]), file=f)
-            #print("\t{", file=f)
             opc.save_dasm(f)
-            #print("\t}", file=f)
+            print("\t\tgoto rop;", file=f)
-            print("\t\tbreak;", file=f)
             print("", file=f)
         print("\t} // switch opcode", file=f)
         print("}", file=f)
@@ -248,7 +253,7 @@ class OpcodeList:
         print("", file=f)
         print("} // switch prefix", file=f)
         print("", file=f)
-        print("m_ref = 0xffff00;", file=f)
+        print("} // while (true)", file=f)
 
 def main(argv):
     if len(argv) != 3 and len(argv) != 4:

src/devices/cpu/z80/z80n.cpp

@@ -31,7 +31,7 @@ z80n_device::z80n_device(const machine_config &mconfig, const char *tag, device_
 {
 }
 
-void z80n_device::do_op()
+void z80n_device::execute_run()
 {
 	#include "cpu/z80/z80n.hxx"
 }

src/devices/cpu/z80/z80n.h

@@ -26,7 +26,8 @@ protected:
 	virtual void device_start() override ATTR_COLD;
 	virtual void device_reset() override ATTR_COLD;
 
-	virtual void do_op() override;
+	// device_execute_interface implementation
+	virtual void execute_run() override;
 
 	devcb_write8 m_out_retn_seen_cb;
 	devcb_read8 m_in_nextreg_cb;