Reconstruct @ MARK source code.

Source text taken from SYSTEM GEN, mostly by removing the HACK things.

src/syseng/mark.1

@@ -0,0 +1,102 @@
+TITLE MARK TAPE
+
+;Reconstructed in 2020 by lightly editing SYSTEM GEN to match @ MARK
+;binary.
+
+MACLOD=37726
+
+A=1
+D=2
+B=3
+C=4
+P=5
+
+
+BEG:	CONO 635550
+TRY:	CONO UTC,203410
+	CONSZ UTS,2000
+	JRST .-1
+	CONSZ UTS,4
+	JRST TRY
+	CONO UTC,221410
+	CONO DC,3410
+	MOVEI B,2700.
+	MOVE A,[707707707707]
+END1:	BLAT
+	SOJG B,END1
+	MOVEI C,1102
+BLK:	MOVE A,[(70707)70770]
+	BLAT
+	MOVE A,[(77070)7000]
+	BLAT
+	HRLI A,7000
+	BLAT
+	HRRI A,-1000
+	BLAT
+	MOVEI B,175
+	HRLI A,-1000
+	BLAT
+	SOJG B,.-1
+	HRRI A,-701
+	BLAT
+	HRLI A,-701
+	BLAT
+	HRRI A,707007
+	BLAT
+	MOVE A,[(700707)70707]
+	BLAT
+	SOJG C,BLK
+	MOVE A,[70070070070]
+	MOVEI B,2700.
+END2:	BLAT
+	SOJG B,END2
+
+TRY2:	CONO UTC,202510
+	CONSZ UTS,2000
+	JRST .-1
+	CONSZ UTS,4
+	JRST TRY2
+	CONO UTC,233510
+	CONO DC,3410
+	MOVEI B,1101
+	MOVEI C,1
+LUP:	MOVEI A,0
+	CAIN C,1
+	MOVE A,B
+	CAIE C,2
+	CAIN C,203
+	MOVE A,234
+	CAIN C,3
+	MOVEI A,77
+	CAIN C,204
+	JRST COMP
+WR:	BLAT
+	SOJG C,LUP
+	MOVEI C,204
+	SOJGE B,LUP
+	CONSZ UTS,40
+	JRST .-1
+
+	CONO UTC,3000
+	CONSZ UTS,2000
+	JRST .-1
+	JRST TRY
+
+WA:	CONSZ UTS,6
+	JRST DING
+	CONSO DC,1000
+	JRST WA
+	DATAO DC,A
+	JRST (P)
+DING:	DATAO TTY,BELL
+	CONO UTC,1000
+	JRST 4,BEG
+BLAT=JSP P,WA
+COMP:	MOVE D,B
+	ROT D,-3
+	REPEAT 3,[ROTC A,3
+	ROT D,-6
+]	ROTC A,27.
+BELL:	SETCAI A,7
+	JRST WR
+	END BEG