Impl vblank irq

1 files changed, 4 insertions, 0 deletions

diff --git a/vdp.hpp b/vdp.hpp
index cd93938..9357377 100644
--- a/vdp.hpp
+++ b/vdp.hpp
@@ -13,6 +13,7 @@ class VDP {
         VDP(const uint32_t base_address_a = VDP_START): base_address(base_address_a) {}
         uint32_t Read(uint32_t offset, enum bitness);
         void Write(uint32_t offset, enum bitness, uint32_t value);
+        bool Scanline(); // Returns true if display disabled or vblank happened
         void Reset();
 
         const uint32_t base_address;
@@ -76,9 +77,12 @@ class VDP {
         static constexpr size_t kVRAMSize = 64*1024;
         static constexpr size_t kCRAMSize = 64*2;
         static constexpr size_t kVSRAMSize = 40*2;
+        static constexpr uint16_t kLinesPerScreenNTSC = 262;
+        static constexpr uint16_t kLinesPerScreenPAL = 312;
 
         StatusRegister _status{};
         bool _control_write_second_word{};
+        uint16_t _lines_counter{};
         uint8_t _address_mode{};
         uint16_t _address{};
         uint8_t _reg[kRegistersCount]{};