Improved graphics performance (callback on memory write)

sample/test.s

@@ -0,0 +1,49 @@
+; head position
+ldx #$00
+stx $00             ; head position low
+ldx #$e0
+stx $01             ; head position high
+
+; colours
+ldx #$f0
+stx $04             ; paint colour
+ldx #$00
+stx $05             ; rubber colour
+
+jsr one
+jsr two
+jsr three
+jsr four
+
+clv
+bvc end
+
+one
+    lda #$50
+    ldx #$00
+    sta ($00, x)
+    inc $00
+    rts
+
+two
+    lda #$F0
+    ldx #$00
+    sta ($00, x)
+    inc $00
+    rts
+
+three
+    lda #$FF
+    ldx #$00
+    sta ($00, x)
+    inc $00
+    rts
+
+four
+    lda #$af
+    ldx #$00
+    sta ($00, x)
+    inc $00
+    rts
+
+end

src/machine/machine.cpp

@@ -77,8 +77,8 @@ namespace emu_6502 {
                 auto byte = read_program_byte();
                 opcode_handler_dir->execute(byte, machine);
 
-                if (terminal_initialised)
-                    terminal->refresh();
+//                if (terminal_initialised)
+//                    terminal->refresh();
             }
         }
     };

src/machine/memory.cpp

@@ -7,6 +7,7 @@ namespace emu_6502 {
 
     Memory::Memory() {
         memory = vector<uint8_t>(0xFFFF);
+        on_write_callbacks = {};
     }
 
     uint8_t Memory::get_at(uint16_t address) {
@@ -15,6 +16,11 @@ namespace emu_6502 {
 
     void Memory::set_at(uint16_t address, uint8_t value) {
         memory.at(address) = value;
+
+        for (auto& cb : on_write_callbacks) {
+            pair<uint16_t, uint8_t> address_value{address, value};
+            cb(address_value);
+        }
     }
 
     uint8_t Memory::get_from_page(uint8_t page, uint8_t offset) {
@@ -24,4 +30,8 @@ namespace emu_6502 {
     void Memory::set_on_page(uint8_t page, uint8_t offset, uint8_t value) {
         set_at(get_page_offset(page) + offset, value);
     }
+
+    void Memory::register_callback(function<void(pair<uint16_t, uint8_t>)> callback) {
+        on_write_callbacks.push_back(callback);
+    }
 }

src/machine/memory.h

@@ -3,6 +3,7 @@
 
 #include <vector>
 #include <cstdint>
+#include <functional>
 
 using namespace std;
 
@@ -10,6 +11,7 @@ namespace emu_6502 {
     class Memory {
     private:
         vector<uint8_t> memory;
+        vector<function<void(pair<uint16_t, uint8_t>)>> on_write_callbacks;
 
         uint16_t get_page_offset(uint8_t page);
 
@@ -23,6 +25,8 @@ namespace emu_6502 {
 
         uint8_t get_from_page(uint8_t page, uint8_t offset);
         void set_on_page(uint8_t page, uint8_t offset, uint8_t value);
+
+        void register_callback(function<void(pair<uint16_t, uint8_t>)> callback);
     };
 }
 

src/machine/terminal.cpp

@@ -15,6 +15,8 @@ namespace emu_6502 {
         for (auto i = LOW_ADDR; i <= HIGH_ADDR; i++) {
             memory.set_at(i, 0);
         }
+
+        memory.register_callback([this](pair<uint16_t, uint8_t> addr_val) { on_memory_written(addr_val); });
     }
 
     Terminal::~Terminal() {
@@ -23,17 +25,32 @@ namespace emu_6502 {
         SDL_Quit();
     }
 
-    void Terminal::refresh() {
-        int x, y = 0;
-        for (auto i = LOW_ADDR; i <= HIGH_ADDR; i++) {
-            x = (i - LOW_ADDR) % WIDTH;
-            y = (i - LOW_ADDR) / HEIGHT;
+//    void Terminal::refresh() {
+//        int x, y = 0;
+//        for (auto i = LOW_ADDR; i <= HIGH_ADDR; i++) {
+//            x = (i - LOW_ADDR) % WIDTH;
+//            y = (i - LOW_ADDR) / HEIGHT;
+//
+//            draw_pixel(x, y, memory.get_at(i));
+//        }
+//
+//        SDL_RenderPresent(renderer);
+//        SDL_Delay(150);
+//    }
 
-            draw_pixel(x, y, memory.get_at(i));
+    void Terminal::on_memory_written(pair<uint16_t, uint8_t> address_value) {
+        uint16_t address = address_value.first;
+
+        if (address >= LOW_ADDR && address <= HIGH_ADDR) {
+            uint8_t colour = address_value.second;
+            int x = (address - LOW_ADDR) % WIDTH;
+            int y = (address - LOW_ADDR) / HEIGHT;
+
+            draw_pixel(x, y, colour);
+
+            SDL_RenderPresent(renderer);
+            SDL_Delay(5);
         }
-
-        SDL_RenderPresent(renderer);
-        //SDL_Delay(20);
     }
 
     void Terminal::draw_pixel(int x, int y, uint8_t colour) {

src/machine/terminal.h

@@ -23,6 +23,7 @@ namespace emu_6502 {
         SDL_Renderer* renderer;
         SDL_Window* window;
 
+        void on_memory_written(pair<uint16_t, uint8_t> address_value);
         void draw_pixel(int x, int y, uint8_t colour);
 
     public:
@@ -31,7 +32,7 @@ namespace emu_6502 {
         Terminal& operator=(const Terminal&) = delete;
         ~Terminal();
 
-        void refresh();
+        //void refresh();
     };
 }
 

src/main.cpp

@@ -12,7 +12,9 @@ using namespace std;
 using namespace emu_6502;
 
 int main() {
-    ifstream in("/home/tony/CLionProjects/6502-emulator/sample/a.o65", ios::binary);
+    string binary = "/home/tony/CLionProjects/6502-emulator/sample/a.o65";
+    //string binary = "/home/tony/Downloads/6502_functional_test.bin";
+    ifstream in(binary, ios::binary);
     if (in.fail())
         throw runtime_error("Failed to read program file");
 
@@ -21,7 +23,7 @@ int main() {
             (istreambuf_iterator<char>()));
 
     auto machine = make_unique<Machine>();
-    machine->load(code, 0x1000);
+    machine->load(code, 0x600);
     machine->execute();
 
     return 0;

src/opcode/handler/jump-opcode-handler-container.cpp

@@ -38,7 +38,7 @@ namespace emu_6502 {
         auto low_byte = machine.get_stack().pop();
         auto high_byte = machine.get_stack().pop();
 
-        uint16_t return_address = (high_byte << 8) + low_byte + 1;
+        uint16_t return_address = (high_byte << 8) + low_byte;// + 1;
         machine.get_cpu().get_pc().set_value(return_address);
     }
 }