Proper ensata handshake on reconnection.

desmume/src/MMU.cpp

@@ -1835,31 +1835,40 @@ static void writereg_POWCNT1(const int size, const u32 adr, const u32 val)
 
 static INLINE void MMU_IPCSync(u8 proc, u32 val)
 {
-	//INFO("IPC%s sync 0x%04X (0x%02X|%02X)\n", proc?"7":"9", val, val >> 8, val & 0xFF);
+
 	u32 sync_l = T1ReadLong(MMU.MMU_MEM[proc][0x40], 0x180) & 0xFFFF;
 	u32 sync_r = T1ReadLong(MMU.MMU_MEM[proc^1][0x40], 0x180) & 0xFFFF;
-
-	sync_l = ( sync_l & 0x000F ) | ( val & 0x0F00 );
-	sync_r = ( sync_r & 0x6F00 ) | ( (val >> 8) & 0x000F );
-
-	sync_l |= val & 0x6000;
-
-	if(nds.ensataEmulation && proc==1 && nds.ensataIpcSyncCounter<9) {
-		u32 iteration = (val&0x0F00)>>8;
-
-		if(iteration==8-nds.ensataIpcSyncCounter)
-			nds.ensataIpcSyncCounter++;
-		else printf("ERROR: ENSATA IPC SYNC HACK FAILED; BAD THINGS MAY HAPPEN\n");
-
-		//for some reason, the arm9 doesn't handshake when ensata is detected.
-		//so we complete the protocol here, which is to mirror the values 8..0 back to 
-		//the arm7 as they are written by the arm7
-		sync_r &= 0xF0FF;
-		sync_r |= (iteration<<8);
-		sync_l &= 0xFFF0;
-		sync_l |= iteration;
+	u32 iterThis = (val & 0x0F00) >> 8;
+
+	sync_l = ( sync_l & 0x000F ) | ( val & 0x6F00 );
+	sync_r = ( sync_r & 0x6F00 ) | ( iterThis );
+
+	// For some reason, the arm9 doesn't handshake when ensata is detected.
+	// So we complete the protocol here, which is to mirror the values 8..0 back to 
+	// The arm7 as they are written by the arm7
+	if (nds.ensataEmulation) {
+
+		if (proc) {
+			// However this hack would break soft reset because it also syncs through ipcsync.
+			// So we have to add some additional checks to ensure that it's handshake instead of reset.
+			if ((iterThis & 8) || (nds.ensataIpcSyncCounter)) {
+				// sync_r = (sync_r & 0xF0FF) | (iterThis << 8); // This is not necessary.
+				sync_l = (sync_l & 0xFFF0) | iterThis;
+				nds.ensataIpcSyncCounter = iterThis;
+			}
+		}
+		else {
+			// After ensata handshake, arm9 will write 0x100 as a signal if Ensata is detected.
+			// This will prevent reset from working, so we have to ignore this.
+			if (nds.ensataHandshake == ENSATA_HANDSHAKE_complete) {
+				nds.ensataHandshake = ENSATA_HANDSHAKE_none;
+				return; 
+			}
+		}
 	}
 
+	// printf("IPCSync(%d, %04x): %04x %04x %d\n", proc, val, sync_l, sync_r, nds.ensataIpcSyncCounter);
+
 	T1WriteLong(MMU.MMU_MEM[proc][0x40], 0x180, sync_l);
 	T1WriteLong(MMU.MMU_MEM[proc^1][0x40], 0x180, sync_r);
 
@@ -4969,7 +4978,7 @@ void FASTCALL _MMU_ARM9_write32(u32 adr, u32 val)
 					//todo - these are usually write only regs (these and 1000 more)
 					//shouldnt we block them from getting written? ugh
 				case eng_3D_CLIPMTX_RESULT:
-					if(nds.ensataEmulation && nds.ensataHandshake == ENSATA_HANDSHAKE_none && val==0x2468ace0)
+					if(nds.ensataEmulation /* && nds.ensataHandshake == ENSATA_HANDSHAKE_none */&& val==0x2468ace0)
 					{
 						printf("ENSATA HANDSHAKE BEGIN\n");
 						nds.ensataHandshake = ENSATA_HANDSHAKE_query;