FIX: SGB packet bits being written directly instead of through a byte…

… buffer. Recently discovered quirk. gbdev/pandocs#509
binarycounter · Nov 11, 2023 · 78f0b54 · 78f0b54
1 parent 1a5cadb
commit 78f0b54
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/Core/SNES/Coprocessors/SGB/SuperGameboy.cpp b/Core/SNES/Coprocessors/SGB/SuperGameboy.cpp
@@ -163,22 +163,27 @@ void SuperGameboy::ProcessInputPortWrite(uint8_t value)
 					LogPacket();
 				}
 			} else {
-				_packetData[_packetByte] &= ~(1 << _packetBit);
+
+				_packetByteBuffer &= ~(1 << _packetBit);
 			}
 			_packetBit++;
 			if(_packetBit == 8) {
+				_packetData[_packetByte] = _packetByteBuffer;
 				_packetBit = 0;
-				_packetByte++;
+				_packetByte++;	
 			}
+
+
 		} else if(value == 0x10) {
 			//1 bit
 			if(_packetByte >= 16) {
 				//Invalid bit
 				_listeningForPacket = false;
 			} else {
-				_packetData[_packetByte] |= (1 << _packetBit);
+				_packetByteBuffer |= (1 << _packetBit);
 				_packetBit++;
 				if(_packetBit == 8) {
+					_packetData[_packetByte] = _packetByteBuffer;
 					_packetBit = 0;
 					_packetByte++;
 				}

diff --git a/Core/SNES/Coprocessors/SGB/SuperGameboy.h b/Core/SNES/Coprocessors/SGB/SuperGameboy.h
@@ -40,6 +40,7 @@ class SuperGameboy : public BaseCoprocessor, public IAudioProvider
 	uint64_t _inputWriteClock = 0;
 	uint8_t _inputValue = 0;	
 	uint8_t _packetData[16] = {};
+	uint8_t _packetByteBuffer = 0x00;
 	uint8_t _packetByte = 0;
 	uint8_t _packetBit = 0;