put in a skeleton execution core so you can see the code with -debug

scripts/src/cpu.lua

@@ -3899,6 +3899,8 @@ end
 --------------------------------------------------
 
 if opt_tool(CPUS, "EVOLUTION") then
+	table.insert(disasm_files , MAME_DIR .. "src/devices/cpu/evolution/evo.cpp")
+	table.insert(disasm_files , MAME_DIR .. "src/devices/cpu/evolution/evo.h")
 	table.insert(disasm_files , MAME_DIR .. "src/devices/cpu/evolution/evod.cpp")
 	table.insert(disasm_files , MAME_DIR .. "src/devices/cpu/evolution/evod.h")
 end

src/devices/cpu/evolution/evo.cpp

@@ -0,0 +1,78 @@
+// license:BSD-3-Clause
+// copyright-holders:David Haywood
+
+#include "emu.h"
+#include "evo.h"
+#include "evod.h"
+
+DEFINE_DEVICE_TYPE(EVOLUTION_CPU, evo_cpu_device, "evo_cpu", "Evolution CPU")
+
+evo_cpu_device::evo_cpu_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+	: cpu_device(mconfig, EVOLUTION_CPU, tag, owner, clock)
+	, m_program_config("program", ENDIANNESS_LITTLE, 16, 24, -1)
+	, m_pc(0), m_program(nullptr), m_icount(0), m_debugger_temp(0)
+{
+}
+
+std::unique_ptr<util::disasm_interface> evo_cpu_device::create_disassembler()
+{
+	return std::make_unique<evolution_disassembler>();
+}
+
+device_memory_interface::space_config_vector evo_cpu_device::memory_space_config() const
+{
+	return space_config_vector {
+		std::make_pair(AS_PROGRAM, &m_program_config)
+	};
+}
+
+void evo_cpu_device::device_start()
+{
+	m_pc = 0;
+	m_debugger_temp = 0;
+	m_program = &space(AS_PROGRAM);
+	state_add(EVO_PC,  "PC", m_debugger_temp).callimport().callexport().formatstr("%08X");
+	state_add(STATE_GENPCBASE, "CURPC", m_debugger_temp).callimport().callexport().noshow();
+	set_icountptr(m_icount);
+}
+
+void evo_cpu_device::state_export(const device_state_entry &entry)
+{
+	switch (entry.index())
+	{
+		case EVO_PC:
+		case STATE_GENPCBASE:
+			m_debugger_temp = m_pc;
+			break;
+	}
+}
+
+void evo_cpu_device::state_import(const device_state_entry &entry)
+{
+	switch (entry.index())
+	{
+		case EVO_PC:
+		case STATE_GENPCBASE:
+			m_pc = (m_debugger_temp & 0xffffffff);
+			break;
+	}
+}
+
+void evo_cpu_device::device_reset()
+{
+	m_pc = 0x400000;
+}
+
+void evo_cpu_device::execute_set_input(int irqline, int state)
+{
+}
+
+void evo_cpu_device::execute_run()
+{
+	while (m_icount > 0)
+	{
+		debugger_instruction_hook(m_pc);
+		m_pc++;
+		m_icount--;
+	}
+}

src/devices/cpu/evolution/evo.h

@@ -0,0 +1,50 @@
+// license:BSD-3-Clause
+// copyright-holders:David Haywood
+
+#ifndef MAME_CPU_EVO_EVO_H
+#define MAME_CPU_EVO_EVO_H
+
+#pragma once
+
+enum
+{
+	EVO_PC = STATE_GENPC
+};
+
+class evo_cpu_device : public cpu_device
+{
+public:
+	evo_cpu_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+
+protected:
+	virtual void device_start() override;
+	virtual void device_reset() override;
+
+	virtual uint32_t execute_min_cycles() const noexcept override { return 5; }
+	virtual uint32_t execute_max_cycles() const noexcept override { return 5; }
+	virtual uint32_t execute_input_lines() const noexcept override { return 0; }
+	virtual void execute_run() override;
+	virtual void execute_set_input(int inputnum, int state) override;
+
+	virtual space_config_vector memory_space_config() const override;
+
+	virtual void state_import(const device_state_entry &entry) override;
+	virtual void state_export(const device_state_entry &entry) override;
+
+	virtual std::unique_ptr<util::disasm_interface> create_disassembler() override;
+
+private:
+	address_space_config m_program_config;
+
+	uint32_t m_pc;
+
+	address_space *m_program;
+	int m_icount;
+
+	uint32_t m_debugger_temp;
+};
+
+
+DECLARE_DEVICE_TYPE(EVOLUTION_CPU, evo_cpu_device)
+
+#endif // MAME_CPU_EVO_EVO_H

src/mame/skeleton/evolution_handheld.cpp

@@ -8,14 +8,16 @@
 #include "speaker.h"
 #include "screen.h"
 
+#include "cpu/evolution/evo.h"
 
 namespace {
 
 class evolution_handheldgame_state : public driver_device
 {
 public:
 	evolution_handheldgame_state(const machine_config &mconfig, device_type type, const char *tag) :
-		driver_device(mconfig, type, tag)
+		driver_device(mconfig, type, tag),
+		m_maincpu(*this, "maincpu")
 	{ }
 
 	void evolhh(machine_config &config);
@@ -25,6 +27,10 @@ class evolution_handheldgame_state : public driver_device
 	virtual void machine_reset() override;
 
 	uint32_t screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect);
+
+	required_device<evo_cpu_device> m_maincpu;
+
+	void evolution_map(address_map &map);
 };
 
 void evolution_handheldgame_state::machine_start()
@@ -44,8 +50,17 @@ uint32_t evolution_handheldgame_state::screen_update(screen_device &screen, bitm
 	return 0;
 }
 
+void evolution_handheldgame_state::evolution_map(address_map &map)
+{
+	map(0x400000, 0x41ffff).rom().region("maincpu", 0x00000);              
+}
+
+
 void evolution_handheldgame_state::evolhh(machine_config &config)
 {
+	EVOLUTION_CPU(config, m_maincpu, XTAL(16'000'000)); 
+	m_maincpu->set_addrmap(AS_PROGRAM, &evolution_handheldgame_state::evolution_map);
+
 	screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_RASTER));
 	screen.set_refresh_hz(60);
 	screen.set_vblank_time(ATTOSECONDS_IN_USEC(0));
@@ -57,7 +72,7 @@ void evolution_handheldgame_state::evolhh(machine_config &config)
 }
 
 ROM_START( evolhh )
-	ROM_REGION32_BE( 0x400000, "nand", 0 )
+	ROM_REGION( 0x400000, "maincpu", 0 )
 	ROM_LOAD( "s29gl032m90tfir4.u4", 0x000000, 0x400000, CRC(c647ca01) SHA1(a88f512d3fe8803dadc4eb6a94b5babd40c698de) )
 ROM_END