From 9e9c15e28975aa84be7caaa05e97f708af055b64 Mon Sep 17 00:00:00 2001
From: Adrian Conlon <adrian.conlon@gmail.com>
Date: Wed, 27 Oct 2021 09:53:58 +0100
Subject: [PATCH] Use C++20 co-routines as generators for opcode suite and test
 generation.

Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
---
 M6502/HarteTest_6502/HarteTest_6502.vcxproj   |  12 +-
 .../HarteTest_6502.vcxproj.filters            |   9 +
 M6502/HarteTest_6502/TestRunner.cpp           |  22 +-
 M6502/HarteTest_6502/TestRunner.h             |  25 +-
 M6502/HarteTest_6502/checker_t.cpp            | 245 ++++++++++++++++++
 M6502/HarteTest_6502/checker_t.h              | 107 ++++++++
 M6502/HarteTest_6502/co_generator_t.h         |  57 ++++
 M6502/HarteTest_6502/element_t.h              |  12 +-
 M6502/HarteTest_6502/opcode_test_suite_t.cpp  |   5 +
 M6502/HarteTest_6502/opcode_test_suite_t.h    |   5 +
 M6502/HarteTest_6502/parser_t.cpp             |   2 +-
 M6502/HarteTest_6502/parser_t.h               |   6 +-
 .../HarteTest_6502/processor_test_suite_t.cpp |  13 +
 M6502/HarteTest_6502/processor_test_suite_t.h |  20 ++
 M6502/HarteTest_6502/state_t.h                |   6 +-
 M6502/HarteTest_6502/tests.cpp                |  61 ++++-
 16 files changed, 560 insertions(+), 47 deletions(-)
 create mode 100644 M6502/HarteTest_6502/checker_t.cpp
 create mode 100644 M6502/HarteTest_6502/checker_t.h
 create mode 100644 M6502/HarteTest_6502/co_generator_t.h
 create mode 100644 M6502/HarteTest_6502/processor_test_suite_t.cpp
 create mode 100644 M6502/HarteTest_6502/processor_test_suite_t.h

diff --git a/M6502/HarteTest_6502/HarteTest_6502.vcxproj b/M6502/HarteTest_6502/HarteTest_6502.vcxproj
index 93577ab..7f99a99 100644
--- a/M6502/HarteTest_6502/HarteTest_6502.vcxproj
+++ b/M6502/HarteTest_6502/HarteTest_6502.vcxproj
@@ -24,6 +24,7 @@
     <ProjectGuid>{894eb6ef-4c8d-4401-bbaa-aba05a021abb}</ProjectGuid>
     <RootNamespace>HarteTest_6502</RootNamespace>
     <ProjectName>HarteTest_6502</ProjectName>
+    <WindowsTargetPlatformVersion>10.0</WindowsTargetPlatformVersion>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
@@ -94,7 +95,7 @@
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
       <PrecompiledHeader>Use</PrecompiledHeader>
     </ClCompile>
     <Link>
@@ -107,7 +108,7 @@
       <WarningLevel>Level3</WarningLevel>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <ControlFlowGuard>false</ControlFlowGuard>
@@ -127,7 +128,7 @@
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
       <PrecompiledHeader>Use</PrecompiledHeader>
     </ClCompile>
     <Link>
@@ -140,7 +141,7 @@
       <WarningLevel>Level3</WarningLevel>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <ControlFlowGuard>false</ControlFlowGuard>
@@ -162,6 +163,7 @@
     <ClCompile Include="element_t.cpp" />
     <ClCompile Include="opcode_test_suite_t.cpp" />
     <ClCompile Include="parser_t.cpp" />
+    <ClCompile Include="processor_test_suite_t.cpp" />
     <ClCompile Include="ram_t.cpp" />
     <ClCompile Include="simdjson\simdjson.cpp">
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">NotUsing</PrecompiledHeader>
@@ -183,11 +185,13 @@
   <ItemGroup>
     <ClInclude Include="array_t.h" />
     <ClInclude Include="byte_t.h" />
+    <ClInclude Include="co_generator_t.h" />
     <ClInclude Include="cycles_t.h" />
     <ClInclude Include="cycle_t.h" />
     <ClInclude Include="element_t.h" />
     <ClInclude Include="opcode_test_suite_t.h" />
     <ClInclude Include="parser_t.h" />
+    <ClInclude Include="processor_test_suite_t.h" />
     <ClInclude Include="ram_t.h" />
     <ClInclude Include="simdjson\simdjson.h" />
     <ClInclude Include="state_t.h" />
diff --git a/M6502/HarteTest_6502/HarteTest_6502.vcxproj.filters b/M6502/HarteTest_6502/HarteTest_6502.vcxproj.filters
index eddd4ad..e487be5 100644
--- a/M6502/HarteTest_6502/HarteTest_6502.vcxproj.filters
+++ b/M6502/HarteTest_6502/HarteTest_6502.vcxproj.filters
@@ -56,6 +56,9 @@
     <ClCompile Include="parser_t.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="processor_test_suite_t.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="stdafx.h">
@@ -97,5 +100,11 @@
     <ClInclude Include="parser_t.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="processor_test_suite_t.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="co_generator_t.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/M6502/HarteTest_6502/TestRunner.cpp b/M6502/HarteTest_6502/TestRunner.cpp
index 465e0a5..fd38f08 100644
--- a/M6502/HarteTest_6502/TestRunner.cpp
+++ b/M6502/HarteTest_6502/TestRunner.cpp
@@ -25,11 +25,11 @@ void TestRunner::lowerPOWER() {
     EightBit::Bus::lowerPOWER();
 }
 
-void TestRunner::addActualCycle(const uint16_t address, const uint8_t value, const std::string action) {
-    m_actualCycles.push_back({ address, value, action });
+void TestRunner::addActualCycle(const uint16_t address, const uint8_t value, std::string_view action) {
+    m_actualCycles.push_back({ address, value, std::string(action) });
 }
 
-void TestRunner::addActualCycle(const EightBit::register16_t address, const uint8_t value, const std::string action) {
+void TestRunner::addActualCycle(const EightBit::register16_t address, const uint8_t value, std::string_view action) {
     addActualCycle(address.word, value, action);
 }
 
@@ -41,8 +41,8 @@ void TestRunner::addActualWriteCycle(const EightBit::register16_t address, const
     addActualCycle(address, value, "write");
 }
 
-void TestRunner::dumpCycles(const std::string which, const actual_cycles_t& events) {
-    m_messages.push_back(which);
+void TestRunner::dumpCycles(std::string_view which, const actual_cycles_t& events) {
+    m_messages.push_back(std::string(which));
     dumpCycles(events);
 }
 
@@ -55,8 +55,8 @@ void TestRunner::dumpCycle(const actual_cycle_t& cycle) {
     dumpCycle(std::get<0>(cycle), std::get<1>(cycle), std::get<2>(cycle));
 }
 
-void TestRunner::dumpCycles(const std::string which, const cycles_t events) {
-    m_messages.push_back(which);
+void TestRunner::dumpCycles(std::string_view which, const cycles_t events) {
+    m_messages.push_back(std::string(which));
     dumpCycles(events);
 }
 
@@ -84,7 +84,7 @@ void TestRunner::initialise() {
     os() << std::hex << std::uppercase;
 }
 
-void TestRunner::raise(const std::string what, const uint16_t expected, const uint16_t actual) {
+void TestRunner::raise(std::string_view what, const uint16_t expected, const uint16_t actual) {
     os()
         << std::setw(2) << std::setfill(' ')
         << what
@@ -94,7 +94,7 @@ void TestRunner::raise(const std::string what, const uint16_t expected, const ui
     pushCurrentMessage();
 }
 
-void TestRunner::raise(const std::string what, const uint8_t expected, const uint8_t actual) {
+void TestRunner::raise(std::string_view what, const uint8_t expected, const uint8_t actual) {
     os()
         << std::setw(2) << std::setfill(' ')
         << what
@@ -106,7 +106,7 @@ void TestRunner::raise(const std::string what, const uint8_t expected, const uin
     pushCurrentMessage();
 }
 
-void TestRunner::raise(const std::string what, const std::string_view expected, const std::string_view actual) {
+void TestRunner::raise(std::string_view what, std::string_view expected, std::string_view actual) {
     os()
         << std::setw(0) << std::setfill(' ')
         << what
@@ -115,7 +115,7 @@ void TestRunner::raise(const std::string what, const std::string_view expected,
     pushCurrentMessage();
 }
 
-bool TestRunner::check(const std::string what, const uint16_t address, const uint8_t expected, const uint8_t actual) {
+bool TestRunner::check(std::string_view what, const uint16_t address, const uint8_t expected, const uint8_t actual) {
     const auto success = actual == expected;
     if (!success) {
         os() << what << ": " << std::setw(4) << std::setfill('0') << (int)address;
diff --git a/M6502/HarteTest_6502/TestRunner.h b/M6502/HarteTest_6502/TestRunner.h
index 2de325b..90d6792 100644
--- a/M6502/HarteTest_6502/TestRunner.h
+++ b/M6502/HarteTest_6502/TestRunner.h
@@ -45,23 +45,30 @@ private:
 
     void pushCurrentMessage();
 
-    void raise(std::string what, uint16_t expected, uint16_t actual);
-    void raise(std::string what, uint8_t expected, uint8_t actual);
-    void raise(std::string what, std::string_view expected, std::string_view actual);
+    void raise(std::string_view what, uint16_t expected, uint16_t actual);
+    void raise(std::string_view what, uint8_t expected, uint8_t actual);
+    void raise(std::string_view what, std::string_view expected, std::string_view actual);
 
     template<class T>
-    bool check(std::string what, T expected, T actual) {
+    bool check(std::string_view what, T expected, T actual) {
         const auto success = actual == expected;
         if (!success)
             raise(what, expected, actual);
         return success;
     }
 
-    bool check(std::string what, uint16_t address, uint8_t expected, uint8_t actual);
+    bool check(std::string_view what, std::string_view expected, std::string_view actual) {
+        const auto success = actual == expected;
+        if (!success)
+            raise(what, expected, actual);
+        return success;
+    }
+
+    bool check(std::string_view what, uint16_t address, uint8_t expected, uint8_t actual);
 
     void addActualCycle(const actual_cycle_t& value);
-    void addActualCycle(uint16_t address, uint8_t value, std::string action);
-    void addActualCycle(EightBit::register16_t address, uint8_t value, std::string action);
+    void addActualCycle(uint16_t address, uint8_t value, std::string_view action);
+    void addActualCycle(EightBit::register16_t address, uint8_t value, std::string_view action);
 
     void addActualReadCycle(EightBit::register16_t address, uint8_t value);
     void addActualWriteCycle(EightBit::register16_t address, uint8_t value);
@@ -78,11 +85,11 @@ private:
         pushCurrentMessage();
     }
 
-    void dumpCycles(std::string which, cycles_t cycles);
+    void dumpCycles(std::string_view which, cycles_t cycles);
     void dumpCycles(cycles_t cycles);
     void dumpCycle(cycle_t cycle);
 
-    void dumpCycles(std::string which, const actual_cycles_t& cycles);
+    void dumpCycles(std::string_view which, const actual_cycles_t& cycles);
     void dumpCycles(const actual_cycles_t& cycles);
     void dumpCycle(const actual_cycle_t& cycle);
 
diff --git a/M6502/HarteTest_6502/checker_t.cpp b/M6502/HarteTest_6502/checker_t.cpp
new file mode 100644
index 0000000..a2ee7d8
--- /dev/null
+++ b/M6502/HarteTest_6502/checker_t.cpp
@@ -0,0 +1,245 @@
+#include "stdafx.h"
+#include "checker_t.h"
+
+std::set<uint8_t> checker_t::m_undocumented_opcodes;
+bool checker_t::m_undocumented_opcodes_initialised = false;
+
+void checker_t::addActualCycle(const uint16_t address, const uint8_t value, const std::string action) {
+    m_actualCycles.push_back({ address, value, action });
+}
+
+void checker_t::addActualCycle(const EightBit::register16_t address, const uint8_t value, const std::string action) {
+    addActualCycle(address.word, value, action);
+}
+
+void checker_t::addActualReadCycle(const EightBit::register16_t address, const uint8_t value) {
+    addActualCycle(address, value, "read");
+}
+
+void checker_t::addActualWriteCycle(const EightBit::register16_t address, const uint8_t value) {
+    addActualCycle(address, value, "write");
+}
+
+void checker_t::dumpCycles(const std::string which, const actual_cycles_t& events) {
+    m_messages.push_back(which);
+    dumpCycles(events);
+}
+
+void checker_t::dumpCycles(const actual_cycles_t& cycles) {
+    for (const auto& cycle : cycles)
+        dumpCycle(cycle);
+}
+
+void checker_t::dumpCycle(const actual_cycle_t& cycle) {
+    dumpCycle(std::get<0>(cycle), std::get<1>(cycle), std::get<2>(cycle));
+}
+
+void checker_t::dumpCycles(const std::string which, const cycles_t events) {
+    m_messages.push_back(which);
+    dumpCycles(events);
+}
+
+void checker_t::dumpCycles(const cycles_t cycles) {
+    for (const auto cycle : cycles)
+        dumpCycle(cycle_t(cycle));
+}
+
+void checker_t::dumpCycle(const cycle_t cycle) {
+    dumpCycle(cycle.address(), cycle.value(), cycle.action());
+}
+
+void checker_t::raise(const std::string what, const uint16_t expected, const uint16_t actual) {
+    os()
+        << std::setw(2) << std::setfill(' ')
+        << what
+        << std::setw(4) << std::setfill('0')
+        << ": expected: " << (int)expected
+        << ", actual: " << (int)actual;
+    pushCurrentMessage();
+}
+
+void checker_t::raise(const std::string what, const uint8_t expected, const uint8_t actual) {
+    os()
+        << std::setw(2) << std::setfill(' ')
+        << what
+        << std::setfill('0')
+        << ": expected: " << (int)expected
+        << " (" << EightBit::Disassembly::dump_Flags(expected) << ")"
+        << ", actual: " << (int)actual
+        << " (" << EightBit::Disassembly::dump_Flags(actual) << ")";
+    pushCurrentMessage();
+}
+
+void checker_t::raise(const std::string what, const std::string_view expected, const std::string_view actual) {
+    os()
+        << std::setw(0) << std::setfill(' ')
+        << what
+        << ": expected: " << expected
+        << ", actual: " << actual;
+    pushCurrentMessage();
+}
+//
+//bool TestRunner::check(const std::string what, const uint16_t address, const uint8_t expected, const uint8_t actual) {
+//    const auto success = actual == expected;
+//    if (!success) {
+//        os() << what << ": " << std::setw(4) << std::setfill('0') << (int)address;
+//        raise(os().str(), expected, actual);
+//    }
+//    return success;
+//}
+//
+
+checker_t::checker_t(const test_t test)
+: m_test(test) {}
+
+void checker_t::initialiseState(EightBit::MOS6502& cpu, EightBit::Ram& ram) {
+
+    const auto initial = test().initial();
+
+    cpu.PC().word = initial.pc();
+    cpu.S() = initial.s();
+    cpu.A() = initial.a();
+    cpu.X() = initial.x();
+    cpu.Y() = initial.y();
+    cpu.P() = initial.p();
+    for (const auto entry : initial.ram()) {
+        const byte_t byte(entry);
+        ram.poke(byte.address(), byte.value());
+    }
+}
+
+void checker_t::initialise(EightBit::Bus& bus) {
+
+    seedUndocumentedOpcodes();
+
+    bus.ReadByte.connect([this, &bus](EightBit::EventArgs&) {
+        addActualReadCycle(bus.ADDRESS(), bus.DATA());
+    });
+
+    bus.WrittenByte.connect([this, &bus](EightBit::EventArgs&) {
+        addActualWriteCycle(bus.ADDRESS(), bus.DATA());
+    });
+
+    os() << std::hex << std::uppercase;
+}
+
+//
+bool checker_t::checkState(EightBit::MOS6502& cpu, EightBit::Ram& ram) {
+
+    const auto expected_cycles = test().cycles();
+    const auto actual_cycles = m_actualCycles;
+    m_cycle_count_mismatch = expected_cycles.size() != actual_cycles.size();
+    if (m_cycle_count_mismatch)
+        return false;
+
+    size_t actual_idx = 0;
+    for (const auto expected_cycle : expected_cycles) {
+        const auto expected = cycle_t(expected_cycle);
+        const auto actual = actual_cycles.at(actual_idx++);   // actual could be less than expected
+        check("Cycle address", expected.address(), std::get<0>(actual));
+        check("Cycle value", expected.value(), std::get<1>(actual));
+        check("Cycle action", expected.action(), std::string_view(std::get<2>(actual)));
+    }
+
+    const auto final = test().final();
+    const auto pc_good = check("PC", final.pc(), cpu.PC().word);
+    const auto s_good = check("S", final.s(), cpu.S());
+    const auto a_good = check("A", final.a(), cpu.A());
+    const auto x_good = check("X", final.x(), cpu.X());
+    const auto y_good = check("Y", final.y(), cpu.Y());
+    const auto p_good = check("P", final.p(), cpu.P());
+
+    bool ram_problem = false;
+    for (const auto entry : final.ram()) {
+        const byte_t byte(entry);
+        const auto ram_good = check("RAM", byte.address(), byte.value(), ram.peek(byte.address()));
+        if (!ram_good && !ram_problem)
+            ram_problem = true;
+    }
+
+    return pc_good && s_good && a_good && x_good && y_good && p_good && !ram_problem;
+}
+//
+void checker_t::pushCurrentMessage() {
+    m_messages.push_back(os().str());
+    os().str("");
+}
+
+//void TestRunner::disassemble(uint16_t address) {
+//    try {
+//        os() << m_disassembler.disassemble(address);
+//    }
+//    catch (const std::domain_error& error) {
+//        os() << "Disassembly problem: " << error.what();
+//    }
+//    pushCurrentMessage();
+//}
+//
+//void TestRunner::check() {
+//    initialise();
+//    raisePOWER();
+//    initialiseState();
+//    const auto pc = CPU().PC().word;
+//    const auto start_opcode = peek(pc);
+//    m_cycles = CPU().step();
+//    lowerPOWER();
+//
+//    m_valid = checkState();
+//
+//    m_undocumented = m_undocumented_opcodes.find(start_opcode) != m_undocumented_opcodes.end();
+//    if (undocumented()) {
+//        m_messages.push_back("Undocumented");
+//        return;
+//    }
+//
+//    if (unimplemented()) {
+//        m_messages.push_back("Unimplemented");
+//        return;
+//    }
+//
+//    if (invalid() && implemented()) {
+//
+//        disassemble(pc);
+//
+//        const auto final = test().final();
+//        raise("PC", final.pc(), CPU().PC().word);
+//        raise("S", final.s(), CPU().S());
+//        raise("A", final.a(), CPU().A());
+//        raise("X", final.x(), CPU().X());
+//        raise("Y", final.y(), CPU().Y());
+//        raise("P", final.p(), CPU().P());
+//
+//        os()
+//            << std::dec << std::setfill(' ')
+//            << "Stepped cycles: " << cycles()
+//            << ", expected events: " << test().cycles().size()
+//            << ", actual events: " << m_actualCycles.size();
+//        pushCurrentMessage();
+//
+//        dumpCycles("-- Expected cycles", test().cycles());
+//        dumpCycles("-- Actual cycles", m_actualCycles);
+//    }
+//}
+//
+void checker_t::seedUndocumentedOpcodes() {
+    if (m_undocumented_opcodes_initialised) return;
+    m_undocumented_opcodes = {
+        0x02, 0x03, 0x04, 0x07, 0x0b, 0x0c, 0x0f,
+        0x12, 0x13, 0x14, 0x17, 0x1a, 0x1b, 0x1c, 0x1f,
+        0x22, 0x23, 0x27, 0x2b, 0x2f,
+        0x32, 0x33, 0x34, 0x37, 0x3a, 0x3b, 0x3c, 0x3f,
+        0x42, 0x43, 0x44, 0x47, 0x4b, 0x4f,
+        0x52, 0x53, 0x54, 0x57, 0x5a, 0x5b, 0x5c, 0x5f,
+        0x62, 0x63, 0x64, 0x67, 0x6b, 0x6f,
+        0x72, 0x73, 0x74, 0x77, 0x7a, 0x7b, 0x7c, 0x7f,
+        0x80, 0x82, 0x83, 0x87, 0x89, 0x8b, 0x8f,
+        0x92, 0x93, 0x97, 0x9b, 0x9c, 0x9e, 0x9f,
+        0xa3, 0xa7, 0xab, 0xaf,
+        0xb2, 0xb3, 0xb7, 0xbb, 0xbf,
+        0xc2, 0xc3, 0xc7, 0xcb, 0xcf,
+        0xd2, 0xd3, 0xd4, 0xd7, 0xda, 0xdb, 0xdc, 0xdf,
+        0xe2, 0xe3, 0xe7, 0xeb, 0xef,
+        0xf1, 0xf2, 0xf3, 0xf4, 0xf7, 0xfa, 0xfb, 0xfc, 0xff,
+    };
+    m_undocumented_opcodes_initialised = true;
+}
diff --git a/M6502/HarteTest_6502/checker_t.h b/M6502/HarteTest_6502/checker_t.h
new file mode 100644
index 0000000..4eff3f5
--- /dev/null
+++ b/M6502/HarteTest_6502/checker_t.h
@@ -0,0 +1,107 @@
+#pragma once
+
+#include <cstdint>
+#include <set>
+
+#include "cycles_t.h"
+#include "cycle_t.h"
+#include "test_t.h"
+
+class checker_t {
+public:
+private:
+    static std::set<uint8_t> m_undocumented_opcodes;
+    static bool m_undocumented_opcodes_initialised;
+
+    const test_t m_test;
+
+    std::ostringstream m_os;
+    std::vector<std::string> m_messages;
+
+    typedef std::tuple<uint16_t, uint8_t, std::string> actual_cycle_t;
+    typedef std::vector<actual_cycle_t> actual_cycles_t;
+    actual_cycles_t m_actualCycles;
+    bool m_cycle_count_mismatch = false;
+
+    //int m_cycles = 0;
+    //bool m_valid = true;
+    //bool m_undocumented = false;
+
+    [[nodiscard]] auto& os() { return m_os; }
+
+    void seedUndocumentedOpcodes();
+    [[nodiscard]] bool checkState(EightBit::MOS6502& cpu, EightBit::Ram& ram);
+
+    void pushCurrentMessage();
+
+    void raise(std::string what, uint16_t expected, uint16_t actual);
+    void raise(std::string what, uint8_t expected, uint8_t actual);
+    void raise(std::string what, std::string_view expected, std::string_view actual);
+
+    template<class T>
+    bool check(std::string what, T expected, T actual) {
+        const auto success = actual == expected;
+        if (!success)
+            raise(what, expected, actual);
+        return success;
+    }
+
+    bool check(std::string what, uint16_t address, uint8_t expected, uint8_t actual);
+
+    //void addActualCycle(const actual_cycle_t& value);
+    void addActualCycle(uint16_t address, uint8_t value, std::string action);
+    void addActualCycle(EightBit::register16_t address, uint8_t value, std::string action);
+
+    void addActualReadCycle(EightBit::register16_t address, uint8_t value);
+    void addActualWriteCycle(EightBit::register16_t address, uint8_t value);
+
+    //void disassemble(uint16_t address);
+
+    template<class T>
+    void dumpCycle(const uint16_t address, const uint8_t value, const T action) {
+        os()
+            << std::setfill('0') << std::hex
+            << "Address: " << std::setw(4) << (int)address
+            << ", value: " << std::setw(2) << (int)value
+            << ", action: " << action;
+        pushCurrentMessage();
+    }
+
+    void dumpCycles(std::string which, cycles_t cycles);
+    void dumpCycles(cycles_t cycles);
+    void dumpCycle(cycle_t cycle);
+
+    void dumpCycles(std::string which, const actual_cycles_t& cycles);
+    void dumpCycles(const actual_cycles_t& cycles);
+    void dumpCycle(const actual_cycle_t& cycle);
+
+
+
+
+
+
+    //[[nodiscard]] auto test() const noexcept { return m_test; }
+    //[[nodiscard]] constexpr const auto& messages() const noexcept { return m_messages; }
+
+    //[[nodiscard]] constexpr auto cycles() const noexcept { return m_cycles; }
+    //[[nodiscard]] constexpr auto valid() const noexcept { return m_valid; }
+    //[[nodiscard]] constexpr auto invalid() const noexcept { return !valid(); }
+    //[[nodiscard]] constexpr auto unimplemented() const noexcept { return invalid() && m_cycle_count_mismatch && (cycles() == 1); }
+    //[[nodiscard]] constexpr auto implemented() const noexcept { return !unimplemented(); }
+    //[[nodiscard]] constexpr auto undocumented() const noexcept { return m_undocumented; }
+    //[[nodiscard]] constexpr auto documented() const noexcept { return !undocumented(); }
+
+    //void check();
+
+
+public:
+    checker_t(const test_t test);
+
+    [[nodiscard]] auto test() const noexcept { return m_test; }
+
+
+    void initialise(EightBit::Bus& bus);
+    void initialiseState(EightBit::MOS6502& cpu, EightBit::Ram& ram);
+
+};
+
diff --git a/M6502/HarteTest_6502/co_generator_t.h b/M6502/HarteTest_6502/co_generator_t.h
new file mode 100644
index 0000000..97c7d91
--- /dev/null
+++ b/M6502/HarteTest_6502/co_generator_t.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <coroutine>
+#include <utility>
+
+// from https://www.scs.stanford.edu/~dm/blog/c++-coroutines.html
+
+template<typename T>
+struct co_generator_t final {
+
+    struct promise_type;
+    using handle_type = std::coroutine_handle<promise_type>;
+
+    struct promise_type {
+        T value_;
+        std::exception_ptr exception_;
+
+        co_generator_t get_return_object() {
+            return co_generator_t(handle_type::from_promise(*this));
+        }
+        std::suspend_always initial_suspend() { return {}; }
+        std::suspend_always final_suspend() noexcept { return {}; }
+        void unhandled_exception() { exception_ = std::current_exception(); }
+        template<std::convertible_to<T> From> // C++20 concept
+        std::suspend_always yield_value(From&& from) {
+            value_ = std::forward<From>(from);
+            return {};
+        }
+        void return_void() {}
+    };
+
+    handle_type h_;
+
+    co_generator_t(handle_type h) : h_(h) {}
+    ~co_generator_t() { h_.destroy(); }
+    explicit operator bool() {
+        fill();
+        return !h_.done();
+    }
+    T operator()() {
+        fill();
+        full_ = false;
+        return std::move(h_.promise().value_);
+    }
+
+private:
+    bool full_ = false;
+
+    void fill() {
+        if (!full_) {
+            h_();
+            if (h_.promise().exception_)
+                std::rethrow_exception(h_.promise().exception_);
+            full_ = true;
+        }
+    }
+};
diff --git a/M6502/HarteTest_6502/element_t.h b/M6502/HarteTest_6502/element_t.h
index 7053df8..6826904 100644
--- a/M6502/HarteTest_6502/element_t.h
+++ b/M6502/HarteTest_6502/element_t.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <string>
+#include <string_view>
 
 #include "simdjson/simdjson.h"
 
@@ -14,10 +14,8 @@ protected:
 
     [[nodiscard]] auto raw() const noexcept { return m_raw; }
 
-    [[nodiscard]] auto at(std::string key) const noexcept { return raw()[key]; }
-    [[nodiscard]] auto operator[](std::string key) const noexcept { return at(key); }
-    [[nodiscard]] auto array_at(std::string key) const noexcept { return at(key).get_array(); }
-    [[nodiscard]] auto integer_at(std::string key) const noexcept { return at(key).get_int64(); }
-
-
+    [[nodiscard]] auto at(std::string_view key) const noexcept { return raw()[key]; }
+    [[nodiscard]] auto operator[](std::string_view key) const noexcept { return at(key); }
+    [[nodiscard]] auto array_at(std::string_view key) const noexcept { return at(key).get_array(); }
+    [[nodiscard]] auto integer_at(std::string_view key) const noexcept { return at(key).get_int64(); }
 };
diff --git a/M6502/HarteTest_6502/opcode_test_suite_t.cpp b/M6502/HarteTest_6502/opcode_test_suite_t.cpp
index 3efbe46..8daa2fa 100644
--- a/M6502/HarteTest_6502/opcode_test_suite_t.cpp
+++ b/M6502/HarteTest_6502/opcode_test_suite_t.cpp
@@ -3,3 +3,8 @@
 
 opcode_test_suite_t::opcode_test_suite_t(const std::string path) noexcept
 : parser_t(path) {}
+
+co_generator_t<test_t> opcode_test_suite_t::generator() {
+	for (const auto element : *this)
+		co_yield test_t(element);
+}
diff --git a/M6502/HarteTest_6502/opcode_test_suite_t.h b/M6502/HarteTest_6502/opcode_test_suite_t.h
index 69ad42c..6d512ab 100644
--- a/M6502/HarteTest_6502/opcode_test_suite_t.h
+++ b/M6502/HarteTest_6502/opcode_test_suite_t.h
@@ -3,14 +3,19 @@
 #include <string>
 
 #include "parser_t.h"
+#include "co_generator_t.h"
+#include "test_t.h"
 
 class opcode_test_suite_t final : public parser_t {
 private:
     [[nodiscard]] auto array() const noexcept { return raw().get_array(); }
 
 public:
+    opcode_test_suite_t() noexcept {}
     opcode_test_suite_t(std::string path) noexcept;
 
     [[nodiscard]] auto begin() const noexcept { return array().begin(); }
     [[nodiscard]] auto end() const noexcept { return array().end(); }
+
+    co_generator_t<test_t> generator();
 };
diff --git a/M6502/HarteTest_6502/parser_t.cpp b/M6502/HarteTest_6502/parser_t.cpp
index 5f5a026..c252248 100644
--- a/M6502/HarteTest_6502/parser_t.cpp
+++ b/M6502/HarteTest_6502/parser_t.cpp
@@ -7,5 +7,5 @@ parser_t::parser_t(const std::string path) noexcept
 : m_path(path) {}
 
 void parser_t::load() {
-    m_raw = m_parser.load(path());
+    m_raw = m_parser.load(m_path);
 }
diff --git a/M6502/HarteTest_6502/parser_t.h b/M6502/HarteTest_6502/parser_t.h
index 2d5c157..8a383ba 100644
--- a/M6502/HarteTest_6502/parser_t.h
+++ b/M6502/HarteTest_6502/parser_t.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <string>
+#include <string_view>
 
 #include "simdjson/simdjson.h"
 
@@ -11,13 +12,14 @@ private:
     // Therefore, it can only be used for one document at a time.
     static simdjson::dom::parser m_parser;
 
-    const std::string m_path;
+    std::string m_path;
     simdjson::dom::element m_raw;
 
 public:
+    parser_t() noexcept {}
     parser_t(std::string path) noexcept;
 
-    [[nodiscard]] constexpr const auto& path() const noexcept { return m_path; }
+    [[nodiscard]] constexpr std::string_view path() const noexcept { return m_path; }
     [[nodiscard]] const auto raw() const noexcept { return m_raw; }
 
     virtual void load();
diff --git a/M6502/HarteTest_6502/processor_test_suite_t.cpp b/M6502/HarteTest_6502/processor_test_suite_t.cpp
new file mode 100644
index 0000000..7778ef6
--- /dev/null
+++ b/M6502/HarteTest_6502/processor_test_suite_t.cpp
@@ -0,0 +1,13 @@
+#include "stdafx.h"
+#include "processor_test_suite_t.h"
+
+#include <filesystem>
+
+processor_test_suite_t::processor_test_suite_t(std::string location) noexcept
+: m_location(location) {
+}
+co_generator_t<opcode_test_suite_t> processor_test_suite_t::generator() {
+    std::filesystem::path directory = location();
+    for (const auto& entry : std::filesystem::directory_iterator{ directory })
+        co_yield opcode_test_suite_t(entry.path().string());
+}
diff --git a/M6502/HarteTest_6502/processor_test_suite_t.h b/M6502/HarteTest_6502/processor_test_suite_t.h
new file mode 100644
index 0000000..e37ab48
--- /dev/null
+++ b/M6502/HarteTest_6502/processor_test_suite_t.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <string>
+#include <string_view>
+
+#include "co_generator_t.h"
+#include "opcode_test_suite_t.h"
+
+class processor_test_suite_t final {
+private:
+	std::string m_location;
+
+public:
+	processor_test_suite_t(std::string location) noexcept;
+
+	std::string_view location() const noexcept { return m_location; }
+
+	co_generator_t<opcode_test_suite_t> generator();
+};
+
diff --git a/M6502/HarteTest_6502/state_t.h b/M6502/HarteTest_6502/state_t.h
index 17e8f7e..eb1983b 100644
--- a/M6502/HarteTest_6502/state_t.h
+++ b/M6502/HarteTest_6502/state_t.h
@@ -1,7 +1,7 @@
 #pragma once
 
 #include <cstdint>
-#include <string>
+#include <string_view>
 
 #include "simdjson/simdjson.h"
 
@@ -10,8 +10,8 @@
 
 class state_t final : public element_t {
 private:
-    [[nodiscard]] auto address_at(std::string key) const noexcept { return (uint16_t)integer_at(key); }
-    [[nodiscard]] auto byte_at(std::string key) const noexcept { return (uint8_t)integer_at(key); }
+    [[nodiscard]] auto address_at(std::string_view key) const noexcept { return (uint16_t)integer_at(key); }
+    [[nodiscard]] auto byte_at(std::string_view key) const noexcept { return (uint8_t)integer_at(key); }
 
 public:
     state_t(simdjson::dom::element input) noexcept;
diff --git a/M6502/HarteTest_6502/tests.cpp b/M6502/HarteTest_6502/tests.cpp
index f02101c..dd1b62b 100644
--- a/M6502/HarteTest_6502/tests.cpp
+++ b/M6502/HarteTest_6502/tests.cpp
@@ -7,10 +7,13 @@
 #include "TestRunner.h"
 #include "test_t.h"
 #include "opcode_test_suite_t.h"
+#include "processor_test_suite_t.h"
+
+#define USE_COROUTINES
 
 int main() {
 
-	std::filesystem::path location = "C:\\github\\spectrum\\libraries\\EightBit\\modules\\ProcessorTests\\6502\\v1";
+    auto directory = std::string("C:\\github\\spectrum\\libraries\\EightBit\\modules\\ProcessorTests\\6502\\v1");
 
     const auto start_time = std::chrono::steady_clock::now();
 
@@ -21,6 +24,42 @@ int main() {
     TestRunner runner;
     runner.initialise();
 
+#ifdef USE_COROUTINES
+
+    processor_test_suite_t m6502_tests(directory);
+    auto opcode_generator = m6502_tests.generator();
+    while (opcode_generator) {
+
+        auto opcode = opcode_generator();
+
+        const auto path = std::filesystem::path(opcode.path());
+        std::cout << "Processing: " << path.filename() << "\n";
+        opcode.load();
+
+        auto test_generator = opcode.generator();
+        while (test_generator) {
+
+            const auto test = test_generator();
+
+            runner.check(test);
+            if (runner.invalid()) {
+                ++invalid_opcode_count;
+                if (runner.unimplemented())
+                    ++unimplemented_opcode_count;
+                if (runner.undocumented())
+                    ++undocumented_opcode_count;
+                std::cout << "** Failed: " << test.name() << "\n";
+                for (const auto& message : runner.messages())
+                    std::cout << "**** " << message << "\n";
+                break;
+            }
+        }
+    }
+
+#else
+
+    std::filesystem::path location = directory;
+
     for (const auto& entry : std::filesystem::directory_iterator{ location }) {
 
         const auto path = entry.path();
@@ -48,13 +87,15 @@ int main() {
         }
     }
 
-    const auto finish_time = std::chrono::steady_clock::now();
-    const auto elapsed_time = finish_time - start_time;
-    const auto seconds = std::chrono::duration_cast<std::chrono::duration<double>>(elapsed_time).count();
-    std::cout
-        << "Elapsed time: " << seconds << " seconds"
-        << ", undocumented opcode count: " << undocumented_opcode_count
-        << ", unimplemented opcode count: " << unimplemented_opcode_count
-        << ", invalid opcode count: " << (invalid_opcode_count - unimplemented_opcode_count)
-        << std::endl;
+#endif
+
+   const auto finish_time = std::chrono::steady_clock::now();
+   const auto elapsed_time = finish_time - start_time;
+   const auto seconds = std::chrono::duration_cast<std::chrono::duration<double>>(elapsed_time).count();
+   std::cout
+       << "Elapsed time: " << seconds << " seconds"
+       << ", undocumented opcode count: " << undocumented_opcode_count
+       << ", unimplemented opcode count: " << unimplemented_opcode_count
+       << ", invalid opcode count: " << (invalid_opcode_count - unimplemented_opcode_count)
+       << std::endl;
 }