fix/add sys comments

src/sys/s2.s

@@ -27,8 +27,8 @@
 
 	" capture display?
 .capt:
-   lac u.ac
+   lac u.ac			" get user AC
-   dac u.dspbuf
+   dac u.dspbuf			" save as user display buffer
    jms movdsp
    jmp sysexit
 

src/sys/s5.s

@@ -242,11 +242,13 @@ dspnl: 0			" only called once!
 dspinit: 0
    lac dspbufp3			" get pointer to dspbuf+3
    dac dsploc			" store location
-   lac o400000			" display "TRAP" instruction
+   lac o400000			" display "TRAP" instruction (end of list)
    dac dspbuf+3			" save in buffer
    dzm dsplno			" clear display line number
    jmp dspinit i
 
+	" "move display" (change display buffer pointer)
+	" called with new buffer pointer in AC??
 movdsp: 0
    iof
    cdf

src/sys/s7.s

@@ -101,7 +101,7 @@ dsprestart:
 
 1: sna ral			" dataphone flag set (bit 7)??
    jmp .+3			"  no
-   raef				" XXX: fix comment
+   raef				" "resume after edges flag"
    jmp piret			" return
    sma				" light pen flags (bit 2)
    jmp 1f			"  no
@@ -114,9 +114,9 @@ dsprestart:
 1: ksf				" (TTY) keyboard flag set?
    jmp 1f			"  no
 
-   lac ttydelay		" get TTY delay
+   lac ttydelay			" get TTY delay
-   sma				"
+   sma				" minus (waiting for output)?
-   isz ttydelay
+   isz ttydelay			"  no: increment??? (make more positive)
    krb				" read keyboard buffer
    dac char			" save in char
    sad o375			" interrupt char (TTY ALT MODE?)
@@ -128,12 +128,12 @@ dsprestart:
    jms wakeup			" wake processes
    dac sfiles+0			" clear sleep word
    lac char			" get character
-   sad o212			" odd condition (break???)
+   sad o212			" new line (with parity)??
    skp				"  yes
    jmp piret			"   no: done
-   lac sfiles+1			" get ttyout wait word
+   lac sfiles+1			" get ttyout sleep word
-   sma				" bit for process 1 already set?
+   sma				" highest bit set?
-   xor o400000			" no, make it so
+   xor o400000			" no, make it so (why???)
    dac sfiles+1			" save back
 
 "** 01-s1.pdf page 43
@@ -259,7 +259,7 @@ ttyrestart: 0
    jmp piret
 
 		"** BEGIN CROSSED OUT
-1: spb					" graphic 2 push button flag set?
+1: spb					" any graphic-2 push button?
    jmp 1f				"  no
 
    cpb					" clear push button flag
@@ -268,11 +268,11 @@ ttyrestart: 0
 
 "** 01-s1.pdf page 45
 
-   and o2000
+   and o2000				" get push button 7
-   sna
+   sna					" set?
-   jmp piret
+   jmp piret				"  no: done
-   jms dspinit
+   jms dspinit				" yes: reset display buffer
-   lac sfiles+6
+   lac sfiles+6				" wake up anyone sleeping on display
    jms wakeup
    dac sfiles+6
    cla					" clear button lights