Add comments to SALV about encoding data for the DC-10.

src/system/salv.315

@@ -1820,27 +1820,27 @@ MARK69:	MOVE I,TOU
 	 IDPB A,C
 	JRST 6TYL
 DC,[
-HCOMP:	SETOM HPAR'
+HCOMP:	SETOM HPAR'		;RESET PARITY
 	MOVEI J,(I)
-	HRLI J,-2
+	HRLI J,-2		;AOBJN POINTER TO TWO 28-BIT WORDS
 HCOMP1:	MOVEI B,14.
-	MOVE A,(J)
+	MOVE A,(J)		;GET WORD
 	XORM A,HPAR
-	LSH A,-2
+	LSH A,-2		;XOR AND SHIFT 2 BITS, 14 TIMES
 	SOJG B,.-2
 	AOBJN J,HCOMP1
 
-	MOVE B,(I)
-	PUSHJ P,ENCH
-	MOVE B,HPAR
+	MOVE B,(I)		;GET FIRST HEADER WORD
+	PUSHJ P,ENCH		;ENCODE IT
+	MOVE B,HPAR		;GET PARITY BITS
 	ANDI B,3
 	LSH B,20.
-	XORB B,1(I)
-	PUSHJ P,ENCH
+	XORB B,1(I)		;ADD TO SECOND HEADER WORD
+	PUSHJ P,ENCH		;ENCODE IT
 	MOVSI B,770000
-HCOMP2:	TDNN B,DSKBP
+HCOMP2:	TDNN B,DSKBP		;PAD OUT THE WORD
 	 POPJ P,
-	PUSHJ P,ENCDO
+	PUSHJ P,ENCDO		;WITH ONES
 	JRST HCOMP2
 
 ENCO:	SKIPA A,C1
@@ -1856,9 +1856,9 @@ ENCT:	ENC1
 
 ENCDO:	SKIPA A,[3]
 ENCDZ:	 MOVEI A,0
-ENCD:	ANDI A,3
+ENCD:	ANDI A,3		;MASK DATA TO TWO BITS
 	HRRZ T,ENCS
-	JRST @ENCDT(T)
+	JRST @ENCDT(T)		;DISPATCH ACCORDING TO STATE
 
 ENCDT:	ENC2A
 	[JRST 4,.]
@@ -1866,25 +1866,25 @@ ENCDT:	ENC2A
 	[JRST 4,.]
 
 ENC1:	HRLM A,ENCS
-ENC1A:	AOS ENCS
+ENC1A:	AOS ENCS		;DATA WAS ZERO, UPDATE STATE
 	POPJ P,
 
 ENC2:	ROT A,-1
 	HLR A,ENCS
 	ROT A,2
 	JRST ENC2B
-ENC2A:	LSH A,1
-	AOS ENCS
-ENC2B:	JUMPE A,ENC1A
-C1:	TRO A,1
-	IDPB A,DSKBP'
-ENC3:	SETZM ENCS
+ENC2A:	LSH A,1			;SHIFT DATA
+	AOS ENCS		;UPDATE STATE
+ENC2B:	JUMPE A,ENC1A		;DATA ZERO
+C1:	TRO A,1			;SET LOW BIT
+	IDPB A,DSKBP'		;STORE
+ENC3:	SETZM ENCS		;RESET STATE
 	POPJ P,
 
 ENCZ2:	ROT A,-1
 	HLR A,ENCS
 	JRST .+2
-ENCZ2A:	 ROT A,-1
+ENCZ2A:	 ROT A,-1		;HERE WHEN PREVIOUS DATA WAS ZERO
 	ASH A,2
 	TRO A,2
 	IDPB A,DSKBP
@@ -1893,11 +1893,11 @@ ENCZ2A:	 ROT A,-1
 	IDPB A,DSKBP
 	JRST ENC3
 
-ENCH:	LSH B,36.-28.
-	SKIPA C,[14.]
-ENCW:	 MOVEI C,18.
-	LSHC A,2
-	PUSHJ P,ENCD
+ENCH:	LSH B,36.-28.		;MOVE 28-BIT DATA TO THE LEFT
+	SKIPA C,[14.]		;C IS NUMBER OF BITS
+ENCW:	 MOVEI C,18.		;B IS DATA
+	LSHC A,2		;MOVE IN TWO BITS FROM B
+	PUSHJ P,ENCD		;ENCODE THOSE
 	SOJG C,.-2
 	POPJ P,