--- xinu/sys/ttyread.c	2018/04/24 17:39:02	1.1.1.1
+++ xinu/sys/ttyread.c	2018/04/24 17:39:17	1.1.1.2
@@ -10,86 +10,61 @@
  *------------------------------------------------------------------------
  */
 ttyread(devptr, buff, count)
-struct	devsw	*devptr;
-int count;
-char *buff;
+	struct	devsw	*devptr;
+	int count;
+	char *buff;
 {
-	PStype ps;
-	register struct	tty *iptr;
-	int avail, nread;
-	char ch, eofch;
-	int	donow, dolater;
+	register struct	tty	*ttyp;
+	int	avail, numread;
 
+#ifdef	DEBUG
+	dotrace("ttyread", &devptr, 3);
+#endif
 	if (count < 0)
 		return(SYSERR);
-	disable(ps);
-	if ( (avail=scount((iptr= &tty[devptr->dvminor])->isem)) < 0)
-		avail = 0;
-	if (count == 0) {	/* read whatever is available */
-		if (avail == 0) {
-			restore(ps);
-			return(0);
-		}
-		count = avail;
+	disable();
+
+	avail = scount( (ttyp= &tty[devptr->dvminor])->isem );
+	if ( (count = (count==0 ? avail : count)) == 0) {
+		restore();
+		return(0);
 	}
-	if (count < avail) {
-		donow = count;
-		dolater = 0;
-	} else {
-		donow = avail;
-		dolater = count - avail;
+	numread = count;
+	if (avail >= count) {
+		readcopy(buff, ttyp, count);
+		restore();
+		return(numread);
 	}
-	nread = 0;
-	if (donow > 0) {
-		ch = iptr->ibuff[iptr->itail++];
-		if (iptr->itail >= IBUFLEN)
-			iptr->itail = 0;
-		if ( ((eofch=iptr->ieofc) == ch) && iptr->ieof) {
-				sreset(iptr->isem, avail-1);
-				restore(ps);
-				return(EOF);
-		}
-		*buff++ = ch;
-		for (nread=1 ; nread < donow ; ) {
-			ch = iptr->ibuff[iptr->itail];
-			if ( (ch==eofch) && iptr->ieof) {
-				sreset(iptr->isem, avail - nread);
-				restore(ps);	
-				return(nread);
-			}
-			*buff++ = ch;
-			if (++iptr->itail >= IBUFLEN)
-				iptr->itail = 0;
-			nread++;
-			if (ch == NEWLINE || ch == RETURN) {
-				sreset(iptr->isem, avail - nread);
-				restore(ps);	
-				return(nread);
-			}
-		}
-		sreset(iptr->isem, avail - nread);
+	if (avail > 0) {
+		readcopy(buff, ttyp, avail);
+		buff += avail;
+		count -= avail;
 	}
-	donow = nread;
-	for (nread=0 ; nread < dolater ; ) {
-		wait(iptr->isem);
-		ch = iptr->ibuff[iptr->itail];
-		if (ch == iptr->ieofc && iptr->ieof) {
-			if (nread == 0 && donow == 0) {
-				if (++iptr->itail >= IBUFLEN)
-				iptr->itail = 0;
-				restore(ps);
-				return(EOF);
-			}
-			signal(iptr->isem);
-			break;
-		}
-		*buff++ = ch;
-		nread++;
-		if (++iptr->itail >= IBUFLEN)
-			iptr->itail = 0;
-		if (ch == NEWLINE || ch == RETURN)
-			break;
+	restore();
+	for ( ; count>0 ; count--)
+		*buff++ = ttygetc(devptr);
+	return(numread);
+}
+
+/*------------------------------------------------------------------------
+ *  readcopy - high speed copy procedure used by ttyread
+ *------------------------------------------------------------------------
+ */
+LOCAL readcopy(buff,ttyp,count)
+register char *buff;
+struct tty *ttyp;
+int count;
+{
+	register char *qtail, *qend, *uend;	/* copy	loop variables	*/
+
+	qtail =	&ttyp->ibuff[ttyp->itail];
+	qend  =	&ttyp->ibuff[IBUFLEN];
+	uend = buff + count;
+	while (	buff < uend ) {
+		*buff++	= *qtail++;
+		if ( qtail >= qend )
+			qtail =	ttyp->ibuff;
 	}
-	restore(ps);
-	return(donow + nread);
+	ttyp->itail = qtail-ttyp->ibuff;
+	sreset(ttyp->isem, scount(ttyp->isem)-count);
 }