From 931d5ef33c84ad3db93bd8baafe8f335b60799a2 Mon Sep 17 00:00:00 2001
From: Jeroen Domburg <git@j0h.nl>
Date: Wed, 18 Oct 2017 15:20:12 +0800
Subject: [PATCH] Add some decoding debug logic

---
 components/tme/scc.c | 84 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 80 insertions(+), 4 deletions(-)

diff --git a/components/tme/scc.c b/components/tme/scc.c
index 42e6719..4ec5cbf 100644
--- a/components/tme/scc.c
+++ b/components/tme/scc.c
@@ -18,7 +18,7 @@ void sccIrq(int ena);
 #define NO_RXBUF 4
 
 typedef struct {
-	int delay; //-1 if buffer is free, 
+	int delay; //-1 if buffer is free
 	int len;
 	uint8_t data[BUFLEN];
 } RxBuf;
@@ -36,6 +36,8 @@ typedef struct {
 	int rxPos;
 	int rxBufCur;
 	int rxDelay;
+	int eofDelay;
+	int eofIntPending;
 } SccChan;
 
 typedef struct {
@@ -49,6 +51,16 @@ typedef struct {
 static Scc scc;
 
 
+/*
+For SCC, Special conditions are:
+- Receive overrun
+- Framing Error (async)
+- End of Frame
+- Optional: Parity error
+
+For the emu (where we atm only do sldc for appletalk) only End Of Frame is important.
+*/
+
 static void triggerRx(int chan);
 
 
@@ -111,11 +123,59 @@ static int rxBufTick(int chan) {
 #define SCC_RR3_CHA_TX  (1<<4)
 #define SCC_RR3_CHA_RX  (1<<5)
 
+static void explainWrite(int reg, int chan, int val) {
+	const static char *cmdLo[]={"null", "point_high", "reset_ext_status_int", "send_ABORT", 
+			"ena_int_on_next_char", "reset_tx_pending", "error_reset", "reset_highest_ius"};
+	const static char *cmdHi[]={"null", "reset_rx_crc", "reset_tx_crc", "reset_tx_underrun_EOM_latch"};
+	const static char *intEna[]={"RxIntDisabled", "RxInt1stCharOrSpecial", "RxIntAllCharOrSpecial", "RxIntSpecial"};
+	const static char *rstDesc[]={"NoReset", "ResetChB", "ResetChA", "HwReset"};
+	if (reg==0 && ((val&0xF8)!=0)) {
+		if (((val&0xF8)!=0) && ((val&0xF8)!=0x08)) {
+			printf("Write reg 0; CmdHi=%s CmdLo=%s\n", cmdHi[(val>>6)&3], cmdLo[(val>>3)&7]);
+		}
+	} else if (reg==1) {
+		printf("Write reg 1 for chan %d: ", chan);
+		if (val&0x80) printf("WaitDmaReqEn ");
+		if (val&0x40) printf("WaitDmaReqFn ");
+		if (val&0x20) printf("WaitDmaOnRxTx ");
+		if (val&0x04) printf("ParityIsSpecial ");
+		if (val&0x02) printf("TxIntEna ");
+		if (val&0x01) printf("RxIntEna ");
+		printf("%s\n", intEna[(val>>3)&3]);
+	} else if (reg==9) {
+		printf("Write reg 9: cmd=%s ", rstDesc[(val>>6)&3]);
+		if (val&0x01) printf("VIS ");
+		if (val&0x02) printf("NV ");
+		if (val&0x04) printf("DLC ");
+		if (val&0x08) printf("MIE ");
+		if (val&0x10) printf("StatusHi ");
+		if (val&0x20) printf("RESVD ");
+		printf("\n");
+	} else if (reg==15) {
+		printf("Write reg 15: ");
+		if (val&0x02) printf("ZeroCountIE ");
+		if (val&0x08) printf("DcdIE ");
+		if (val&0x10) printf("SyncHuntIE ");
+		if (val&0x20) printf("CtsIE ");
+		if (val&0x40) printf("TxUnderrunIE ");
+		if (val&0x80) printf("BreakAbortIE ");
+		printf("\n");
+	} else {
+		printf("Write chan %d reg %d val 0x%02X\n", chan, reg, val);
+	}
+}
 
+//Raises an interrupt if needed, specifically when intpending indicates so. Need to 
+//change intpending beforehand.
 static void raiseInt(int chan) {
+	const char *desc[]={"CHB_EXT", "CHB_TX", "CHB_RX", "CHA_EXT", "CHA_TX", "CHA_RX"};
 	if ((scc.chan[chan].wr1&1) ){ //&& (scc.intpending&(~scc.intpendingOld))) {
 		scc.intpendingOld=scc.intpending;
-		printf("SCC int, pending %x\n", scc.intpending);
+		printf("SCC int, pending %x: ", scc.intpending);
+		for (int i=0; i<6; i++) {
+			if (scc.intpending&(1<<i)) printf("%s ", desc[i]);
+		}
+		printf("\n");
 		sccIrq(1);
 	}
 }
@@ -195,6 +255,7 @@ static void triggerRx(int chan) {
 			raiseInt(chan);
 		}
 		scc.chan[chan].hunting=0;
+		scc.chan[chan].eofDelay=scc.chan[chan].rx[bufid].len*3;
 	} else {
 		printf("...Not for us, ignoring.\n");
 		rxBufIgnoreRest(chan);
@@ -212,7 +273,7 @@ void sccWrite(unsigned int addr, unsigned int val) {
 		reg=scc.regptr;
 		scc.regptr=0;
 	}
-	
+	explainWrite(reg, chan, val);
 	if (reg==0) {
 		scc.regptr=val&0x7;
 		if ((val&0x38)==0x8) scc.regptr|=8;
@@ -251,7 +312,7 @@ void sccWrite(unsigned int addr, unsigned int val) {
 		scc.chan[chan].wr15=val;
 		raiseInt(chan);
 	}
-	printf("SCC: write to addr %x chan %d reg %d val %x\n", addr, chan, reg, val);
+//	printf("SCC: write to addr %x chan %d reg %d val %x\n", addr, chan, reg, val);
 }
 
 
@@ -267,6 +328,8 @@ unsigned int sccRead(unsigned int addr) {
 		scc.regptr=0;
 	}
 	if (reg==0) {
+		//Actually, the bits in this register that have an associated external/status int will be
+		//latched when that int is triggered. Yah...
 		if (rxHasByte(chan)) val|=(1<<0);
 		//Bit 1 is zero count - never set
 		val=(1<<2); //tx buffer always empty
@@ -354,6 +417,19 @@ void sccTick() {
 		if (rxBufTick(n)) {
 			triggerRx(n);
 		}
+		if (scc.chan[n].eofDelay>0) {
+			scc.chan[n].eofDelay--;
+			if (scc.chan[n].eofDelay==0 && (scc.chan[n].wr1&0x10)!=0) {
+				//Int mode is recv char or special / special only
+				printf("Raise EOF int for channel %d\n", n);
+				scc.chan[n].eofIntPending=1;
+				scc.intpending|=((n==0)?SCC_RR3_CHA_RX:SCC_RR3_CHB_RX);
+				raiseInt(n);
+			}
+			//Break/Abort
+			scc.intpending|=(n?SCC_RR3_CHA_EXT:SCC_RR3_CHB_EXT);
+			raiseInt(n);
+		}
 	}
 }