;-------------------------------
; #GAMCO
; bad block check POKEd into memory
; from compiled BASIC
; e.g. Essential Grammar, Math Football
;-------------------------------
!zone {
; [speed optimization: only ever seen this protection on disks with
;  a specific nibble sequence on track $22, or an unformatted T22 --
;  if this global variable is set in SkipTrack() after failing to read T22S0F,
;  then we scan every other track for the Gamco protection code]
         lda   gPossibleGamco
         bne   .exit
         ldy   #$12
         jsr   SearchTrack
         !byte $33,$32,$01,$30,$03,$31,$39,$31
         !byte $03,$31,$32,$38,$02,$31,$31,$02
         !byte $39,$36
         bcs   .var2      ; passport-test-suite/Essential Grammar.woz [C=0] matches
         jsr   PrintByID
         !byte s_poke
         jsr   modify
         !byte $34,$34,$01,$30,$02,$31,$30,$03
         !byte $32,$33,$34,$03,$31,$36,$39,$02
         !byte $33,$39
         bvc   .exit
.var2
         ldy   #$12
         jsr   SearchTrack
         !byte $32,$01,$30,$03,$31,$39,$31,$03
         !byte $31,$32,$38,$03,$32,$35,$30,$02
         !byte $33,$31
         bcs   .exit      ; passport-test-suite/Percent (Gamco).woz [C=0] matches
         jsr   PrintByID
         !byte s_poke
         jsr   modify
         !byte $36,$01,$30,$03,$31,$36,$39,$03
         !byte $31,$32,$38,$03,$31,$36,$39,$02
         !byte $33,$39
.exit
}