Added PORTS.

Resolves #123.

README.md

@@ -169,6 +169,7 @@ A list of [known ITS machines](doc/machines.md).
    - PEEK, system monitoring.
    - PFTHMG, Puff the magic dragon.
    - PHOTO, capture STY session output.
+   - PORTS, display free network ports.
    - PR, print out various system documentation.
    - PROBE, probe inside job and display various information about it.
    - PRUFD, list files on disk volume.

build/build.tcl

@@ -752,6 +752,10 @@ expect ":KILL"
 respond "*" ":midas sys1;ts timoon_syseng;timoon\r"
 expect ":KILL"
 
+# ports
+respond "*" ":midas sys2;ts ports_sysen2;ports\r"
+expect ":KILL"
+
 # sysmsg
 respond "*" ":midas sys1;ts sysmsg_sysen1;sysmsg\r"
 expect ":KILL"

src/sysen2/ports.1

@@ -0,0 +1,108 @@
+;-*-midas-*-
+
+title ports-> print number of free net ports.
+;Stolen from RMS's LOADP, and prettied up a bit.
+
+a=1
+b=2
+c=3
+d=4
+e=5
+f=6
+g=7
+h=10
+i=11
+j=12
+k=13
+l=14
+m=15
+n=16
+p=17
+t1=20
+t2=21
+chttyo==1
+
+define syscal a,b
+	.call [setz ? sixbit/a/ ? b ((setz))]
+termin
+DEFINE TCAL OP,ARGS
+	.CALL [SETZ ? SIXBIT /OP/ ? ARGS ((SETZ))]
+TERMIN
+DEFINE TYPE CHNL,&STRING
+	MOVEI T1,<.LENGTH STRING>
+	MOVE T2,[440700,,[ASCII STRING]]
+	TCAL SIOT,[%CLIMM,,CHNL ? T2 ? T1]
+	  .LOSE %LSFIL
+TERMIN
+
+
+
+beg:	move p,[-lpdl,,pdl]
+	.open chttyo,[.uao,,'tty]
+	 .lose
+	movei b,0		;B indexes which tty we are looking at.
+	setzm nfstys		;Initialize counters: # of free stys
+count:	syscal ttyget,[%climm,,400000(b) ;D gets TTYST var - negative for free tty.
+			%clout,,a ? %clout,,a ? %clout,,d]
+	 jrst print		;Error means we have run out of tty numbers.
+	syscal ttyvar,[%climm,,400000(b) ? [sixbit/ttytyp/]
+			%clout,,a]
+	 .lose %lsfil
+	trnn a,%tysty		;If it's a sty, is it free?
+	 jrst notfre
+	jumpge d,notfre
+	aos nfstys
+notfre:	aoja b,count		;ok, it isn't free, ignore it.
+
+ascout:	hrli a,440700
+ascou1:	ildb b,a
+	jumpe b,cpopj
+	.iot chttyo,b
+	jrst ascou1
+
+decout:	idivi a,10.
+	hrlm b,(p)
+	skipe a
+	 pushj p,decout
+	hlrz b,(p)
+	addi b,"0
+	.iot chttyo,b
+cpopj:	popj p,
+
+;Having collected the data, print it out.
+print:	move a,nfstys
+	cain a,0
+	 jrst print0
+	cain a,1
+	 jrst print1
+	movei a,[asciz/There are /]
+	pushj p,ascout
+	move a,nfstys
+	pushj p,decout
+	movei a,[asciz/ free net ports.
+/]
+	pushj p,ascout
+	.logout 1,
+
+
+print1:	movei a,[asciz/There is 1 free net port.
+/]
+	pushj p,ascout
+	.logout 1,
+
+print0:	movei a,[asciz/There are no free net ports.
+/]
+	pushj p,ascout
+	.logout 1,
+
+
+nfstys:	0
+
+pat: patch:
+	block 40
+epatch:	-1
+
+lpdl=10
+pdl:	block lpdl
+
+	end beg