Reduce the direct use of the Kernal variable IOStatus by using the Kernal API routine READST.

Also remove the code referencing the old R38 RAM/ROM bank switching registers.
Finally remove some unused Kernal variable labels.

6502/C64/src/vf-sys-c16.fth

@@ -9,11 +9,10 @@ include vf-lbls-cbm.fth
 0ff4c >label ConOut
   090 >label IOStatus
   09a >label MsgFlg
+  0ae >label CurDev
 0ff19 >label BrdCol
 0ff15 >label BkgCol
  053b >label PenCol
-  09d >label PrgEnd  \ aka eal; seems unused
-  0b2 >label IOBeg   \ aka stal; seems unused
   0cb >label CurFlg
   0cf >label InsCnt
  0540 >label KeyRep

6502/C64/src/vf-sys-c64.fth

@@ -12,8 +12,6 @@ include vf-lbls-cbm.fth
 0d020 >label BrdCol
 0d021 >label BkgCol
  0286 >label PenCol
-  0ae >label PrgEnd  \ aka eal; seems unused
-  0c1 >label IOBeg   \ aka stal; seems unused
   0d4 >label CurFlg
   0d8 >label InsCnt
  028a >label KeyRep

6502/C64/src/vf-sys-cbm.fth

@@ -151,10 +151,11 @@ Label nodevice     0 # ldx  1 # ldy
 \ ?device                     clv12jul87
 
 Label (?dev
- IOStatus stx (C16 $ae sta ( ) LISTEN jsr
-        \ because of error in OS
+ IOStatus stx  \ because IOStatus isn't cleared by LISTEN or TALK
+ (C16 CurDev sta ( )  \ current device number - because of error in OS
+ LISTEN jsr
  60 # lda  SECOND jsr  UNLSN jsr
- IOStatus lda  0<> ?[ pla pla nodevice jmp ]?
+ READST jsr  0<> ?[ pla pla nodevice jmp ]?
  rts    end-code
 
  Code (?device  ( dev --)

6502/C64/src/vf-sys-x16.fth

@@ -12,20 +12,12 @@ include vf-lbls-cbm.fth
 09f2c >label BrdCol
  0266 >label BkgCol
  0284 >label PenCol
-   8a >label PrgEnd  \ aka eal; seems unused
- 0292 >label IOBeg   \ aka stal; seems unused
  0381 >label CurFlg  \ aka qtsw
  0385 >label InsCnt  \ aka insrt
 
-\ TODO(issues/33): Remove the R?mBank38 labels.
-09f60 >label RomBank38
-09f61 >label RamBank38
 1 >label RomBank
 0 >label RamBank
 
-0a000 >label KeyD  \ keyboard buffer
-0a00a >label Ndx   \ #keys in keyboard buffer
-
   037B >label blnsw  \ C64: $cc
 \   037C >label blnct  \ C64: $cd
 \   037D >label gdbln  \ C64: $ce
@@ -102,8 +94,6 @@ Label restore   pha txa pha tya pha cld
 Label first-init
  sei cld
  RomBank lda  $f8 # and  RomBank sta \ map in KERNAL ROM
-\ TODO(issues/33): Remove this line accessing RomBank38.
- RomBank38 lda  $f8 # and  RomBank38 sta \ map in KERNAL ROM for R38
  IOINIT jsr  CINT jsr  RESTOR jsr  \ init. and set I/O-Vectors
  ink-pot    lda BrdCol sta \ border
  ink-pot 1+ lda BkgCol sta \ backgrnd