Fix two-byte read and write in VDP

1 files changed, 11 insertions, 8 deletions

diff --git a/vdp.cpp b/vdp.cpp
index d870fce..0ac6e1b 100644
--- a/vdp.cpp
+++ b/vdp.cpp
@@ -17,7 +17,7 @@ uint32_t VDP::Read(const uint32_t offset, const enum bitness bitness)
     }
     if (bitness == BITNESS_32) {
         if (offset == 0) {
-            const auto ret = readData(_address_mode, _address & 0xfffe);
+            const uint16_t ret = readData(_address_mode, _address & 0xfffe);
             _address += _reg[static_cast<size_t>(RegID::kAutoIncrement)];
             return ret;
         } else if (offset == 4) {
@@ -25,7 +25,7 @@ uint32_t VDP::Read(const uint32_t offset, const enum bitness bitness)
         }
     } else if (bitness == BITNESS_16) {
         if (offset == 0 || offset == 2) {
-            const auto ret = readData(_address_mode, _address & 0xfffe);
+            const uint16_t ret = readData(_address_mode, _address & 0xfffe);
             _address += _reg[static_cast<size_t>(RegID::kAutoIncrement)];
             return ret;
         } else if (offset == 4 || offset == 6) {
@@ -101,7 +101,8 @@ void VDP::writeData(const uint8_t address_mode, const uint16_t address, const ui
         if (DEBUG_TRACE_VDP_ACCESS) {
             printf(": VRAM @0x%04x 0x%04x", address, value);
         }
-        _vram[address] = value;
+        _vram[address] = (value >> 8) & 0xff;;
+        _vram[address + 1] = value & 0xff;;
         return;
     case AddressMode::kCRAMWrite:
         if (address >= kCRAMSize) {
@@ -113,7 +114,8 @@ void VDP::writeData(const uint8_t address_mode, const uint16_t address, const ui
         if (DEBUG_TRACE_VDP_ACCESS) {
             printf(": CRAM @0x%04x 0x%04x", address, value);
         }
-        _cram[address] = value;
+        _cram[address] = (value >> 8) & 0xff;;
+        _cram[address + 1] = value & 0xff;;
         return;
     case AddressMode::kVSRAMWrite:
         if (address >= kVSRAMSize) {
@@ -125,7 +127,8 @@ void VDP::writeData(const uint8_t address_mode, const uint16_t address, const ui
         if (DEBUG_TRACE_VDP_ACCESS) {
             printf(": VSRAM @0x%04x 0x%04x", address, value);
         }
-        _vsram[address] = value;
+        _vsram[address] = (value >> 8) & 0xff;;
+        _vsram[address + 1] = value & 0xff;;
         return;
     case AddressMode::kVRAMRead:
     case AddressMode::kCRAMRead:
@@ -194,7 +197,7 @@ uint16_t VDP::readData(const uint8_t address_mode, const uint16_t address)
             }
             return 0;
         } else {
-            const auto value = _vram[address];
+            const uint16_t value = (_vram[address] << 8) | _vram[address + 1];
             if (DEBUG_TRACE_VDP_ACCESS) {
                 printf(": VRAM @0x%04x 0x%04x", address, value);
             }
@@ -207,7 +210,7 @@ uint16_t VDP::readData(const uint8_t address_mode, const uint16_t address)
             }
             return 0;
         } else {
-            const auto value = _cram[address];
+            const uint16_t value = (_cram[address] << 8) | _cram[address + 1];
             if (DEBUG_TRACE_VDP_ACCESS) {
                 printf(": CRAM @0x%04x 0x%04x", address, value);
             }
@@ -220,7 +223,7 @@ uint16_t VDP::readData(const uint8_t address_mode, const uint16_t address)
             }
             return 0;
         } else {
-            const auto value = _vsram[address];
+            const uint16_t value = (_vsram[address] << 8) | _vsram[address + 1];
             if (DEBUG_TRACE_VDP_ACCESS) {
                 printf(": VSRAM @0x%04x 0x%04x", address, value);
             }