SG1000: Guard cartridge RAM writes

drhelius · drhelius · commit ce9741a2b0db · 2026-06-09T23:37:32.000+02:00
diff --git a/src/SG1000MemoryRule.cpp b/src/SG1000MemoryRule.cpp
@@ -65,7 +65,10 @@ void SG1000MemoryRule::PerformWrite(u16 address, u8 value)
     else if (address < 0x4000)
     {
         // On-cartridge RAM ($2000-$3FFF)
-        m_pMemory->Load(address, value);
+        if (m_pCartridge->HasRAMWithoutBattery())
+            m_pMemory->Load(address, value);
+        else
+            Debug("--> ** Attempting to write on ROM address $%X %X", address, value);
     }
     else if (address < 0x8000)
     {

Original file line number	Diff line number	Diff line change
`@@ -65,7 +65,10 @@ void SG1000MemoryRule::PerformWrite(u16 address, u8 value)`
`65`	`65`	`else if (address < 0x4000)`
`66`	`66`	`{`
`67`	`67`	`// On-cartridge RAM ($2000-$3FFF)`
`68`		`- m_pMemory->Load(address, value);`
	`68`	`+ if (m_pCartridge->HasRAMWithoutBattery())`
	`69`	`+ m_pMemory->Load(address, value);`
	`70`	`+ else`
	`71`	`+ Debug("--> ** Attempting to write on ROM address $%X %X", address, value);`
`69`	`72`	`}`
`70`	`73`	`else if (address < 0x8000)`
`71`	`74`	`{`