VERSA: Add support for XGP ;LFTMAR and ;TOPMAR.

Since this means adding support for parsing numeric arguments in XGP
control lines, also check that ;SKIP's argument is 1.

src/dcp/versa.211

@@ -4328,9 +4328,12 @@ xgp50:	call mapper"finish	;"no longer need the file
 	call plot"finish	;"finished plotting (for this file)
 	return			;and th.th.th.that's all folks
 
-.scalar nskip,ksetok
+.scalar nskip,ksetok,lftmar,topmar
 scrimp:	setzm nskip
 	setzm ksetok
+	movei a,128
+	movem a,topmar
+	movem a,lftmar
 scrmor:	call mapper"nxtbyt	;"
 	 jrst scrfin
 	cain x,";		;"
@@ -4349,8 +4352,9 @@ scrfin:	skipn ksetok
 		movei x,string"badreq	;"
 		call util"throw	;"
 		]
-	skipn nskip
-	 jrst [	movei x,[ [asciz "~%~T  XGP: File error: no ;SKIP command"]]
+	movei 1
+	came nskip
+	 jrst [	movei x,[ [asciz "~%~T  XGP: File error: must have ;SKIP 1"]]
 		call log"log	;"
 		movei x,string"badreq	;"
 		call util"throw	;"
@@ -4362,7 +4366,11 @@ scrcom:	call scrget		;get the command
 	camn a,['kset]
 	 jrst scrkset		;get fonts
 	camn a,['skip]
-	 jrst scrskip		;do a ;skip (assume 1 for now)
+	 jrst scrskip		;do a ;skip
+	camn a,['lftmar]
+	 jrst scrlft
+	camn a,['topmar]
+	 jrst scrtop
 	jrst scrloo		;ignore rest
 
 scrget:	setzi a,
@@ -4377,9 +4385,29 @@ scrge2:	call mapper"nxtbyt	;"
 	addi a,(x)
 	jrst scrge2
 
+scrnum:	setzi a,		;read numeric arg into a
+scrnm2:	call mapper"nxtbyt
+	 return			;eof
+	cail	x,"0		;"numeric?
+	 caile	x,"9		;"
+	  return		;no, done
+	subi x,"0
+	imuli a,10
+	add a,x
+	jrst scrnm2
+
 scrskip:
-	setom nskip
-	jrst scrloo		;assume just one for now
+	call scrnum
+	movem a,nskip
+	jrst scrloo
+
+scrlft:	call scrnum
+	movem a,lftmar
+	jrst scrloo
+
+scrtop:	call scrnum
+	movem a,topmar
+	jrst scrloo
 
 .vector ksetbf(50.),ksetfi(4)
 .scalar ksetnm,ksetmr
@@ -4466,7 +4494,8 @@ xarg2:	call xarg1
 	return
 
 dopage:	setzm eopp		;not end of page
-	setzm scanln
+	move y,topmar
+	movem y,scanln
 ;	setzm nscanl		;next scan line
 dopag1:	call doline
 	 jrst [			;end of page, maybe end of file
@@ -4479,6 +4508,8 @@ doline:	setzm outena		;disable output
 	setzm chrrct		;should really be current height??
 	setzm movdwn		;nothing forced us down yet
 	setzm count		;count of saved characters
+	move x,lftmar		;underline from left margin by default
+	movem x,stubit
 	move x,[440700,,rescan]
 	movem x,ptr
 	call dolin1
@@ -4550,8 +4581,8 @@ linfin:	skipn outena
 		return]
 	return
 
-cretrn:				;get leftmargin
-	movem x,xgp.x
+cretrn:	move lftmar		;get leftmargin
+	movem xgp.x
 	aos (p)
 	return