verify Infocom 18-sector format

src/apicode.a

@@ -53,6 +53,11 @@
                           ; reset before each operation
                           ; set in IDBootloader() after reading T00,S00
 
+;gIsInfocom18
+         !byte FALSE      ; 0=true, 1=false
+                          ; reset before each operation
+                          ; set in IDBootFailure() after reading T00
+
 FIRSTFILTER
 ;gIsRDOS
          !byte FALSE      ; 0=true, 1=false

src/apidefs.a

@@ -99,8 +99,10 @@ gIsPanglosDOS                 = gIsAdvent-$01                     ; byte
 gIsDavidson                   = gIsPanglosDOS-$01                 ; byte
 gIsRDOS13                     = gIsDavidson-$01                   ; byte
 ;LASTFILTER ; add new gIs* above this line
+;gIsInfocom18 is a special case whose ID is not in the regular inspection path
+gIsInfocom18                  = gIsRDOS13-$01                     ; byte
 ;gMECCFastloadType is a special case integer whose default value cannot be #FALSE
-gMECCFastloadType             = gIsRDOS13-$01                     ; byte
+gMECCFastloadType             = gIsInfocom18-$01                  ; byte
 
 gOnAClearDayYouCanReadForever = gMECCFastloadType-$01             ; byte
 gUsingRAMDisk                 = gOnAClearDayYouCanReadForever-$01 ; byte
@@ -168,6 +170,7 @@ ConstructStandardDelivery = jConstructStandardDelivery
 !warn "gIsPanglosDOS=",gIsPanglosDOS
 !warn "gIsDavidson=",gIsDavidson
 !warn "gIsRDOS13=",gIsRDOS13
+!warn "gIsInfocom18=",gIsInfocom18
 !warn "gOnAClearDayYouCanReadForever=",gOnAClearDayYouCanReadForever
 !warn "gUsingRAMDisk=",gUsingRAMDisk
 !warn "gRAMDiskRef=",gRAMDiskRef

src/id/inspect0.a

@@ -18,6 +18,14 @@ IDBootloader
          bne   -
          stx   gMECCFastloadType
          stx   gLastTrack
+
+         lda   gIsInfocom18
+         bne   .sanity
+         lda   #s_infocom18
+         jsr   PrintByID
+         jmp   UseUniversal
+
+.sanity
 ;
 ; Quick sanity check -- only recognized values for $0800
 ; are 1 or 2 for regular disks, and 5 for possible Electronic Arts.
@@ -288,3 +296,92 @@ PrereadT00Partial
 .exit
          rts
 }
+
+;-------------------------------
+; IDBootFailure
+; main entry point to identify the bootloader
+; when the initial read failed
+; identifies Infocom 18-sector side B disks
+; doubles as verification routine after ID
+; written by qkumba
+;
+; in:    nothing
+; out:   carry set if we can't ID it
+;-------------------------------
+!zone {
+IDBootFailure
+         lda   #FALSE
+         sta   gIsInfocom18
+         bit   gMode      ; only in verify-mode
+         bmi   .branchno
+
+VerifyInfocom18
+         lda   $C0E9
+         lda   #$1A       ; the length of a track
+         sta   tmp        ; keep X register free
+         ldy   #0
+
+-        iny
+         bne   +
+         dec   tmp
+         beq   .branchno
++        lda   $C0EC
+         bpl   -
+--       cmp   #$D5
+         bne   -
+-        lda   $C0EC
+         bpl   -
+         cmp   #$AA
+         bne   --
+-        lda   $C0EC
+         bpl   -
+         cmp   #$AD
+         beq   .tryinfocom
+         ldx   gIsInfocom18
+         beq   --         ; resume if already in Infocom mode
+         ;;other things here in future
+.branchno
+         jmp   .no
+
+.tryinfocom
+-        lda   $C0EC
+         bpl   -
+         nop
+         nop              ; ignore half of 4x4 track number
+-        lda   $C0EC
+         bpl   -          ; ignore half of 4x4 track number
+
+         lda   #$12       ; all 18 sectors when in verify mode
+         ldx   gIsInfocom18
+         beq   .setcount
+         lda   #$01       ; only one sector when in ID mode
+.setcount
+         sta   tmp        ; sector counter
+
+         lda   #$00
+--       ldy   #$56
+-        ldx   $C0EC
+         bpl   -
+         eor   $BA00,x    ; from universal RWTS
+         dey
+         bne   -
+-        ldx   $C0EC
+         bpl   -
+         eor   $BA00,x    ; from universal RWTS
+         iny
+         bne   -
+-        ldx   $C0EC
+         bpl   -
+         eor   $BA00,x    ; from universal RWTS
+         bne   .no
+         dec   tmp
+         bne   --
+         sta   gIsInfocom18
+         clc              ; all clear
+         !byte $24
+.no
+         sec
+         lda   $C0E8
+         rts
+
+}

src/passport.a

@@ -274,6 +274,8 @@ Reaction
          jsr   IgnoreAddressChecksum
          jsr   ReadSector
          bcc   +
+         jsr   IDBootFailure ; /src/id/inspect0
+         bcc   +
          lda   #s_fail
          jsr   PrintByID
          lda   #s_fatal0000
@@ -375,11 +377,20 @@ ReadWithRWTS
          sta   checksector+2
 .read
          lda   KEY
-         bpl   checksector
+         bpl   .checkinfocom
          bit   STROBE
          cmp   #$e0 ;ignore backtick (MAME debug break)
-         beq   checksector
+         beq   .checkinfocom
          jmp   Cancel
+.checkinfocom
+         lda   gIsInfocom18
+         bne   checksector
+         jsr   VerifyInfocom18
+         bcc   .passtrack
+         jmp   FatalError
+.passtrack
+         jmp   .prevtrack
+
 checksector
          lda   $FFFF                            ; status of current sector in sector map (modified above)
          pha
@@ -387,10 +398,8 @@ checksector
          bcc   +
          cmp   #kSectorCustomLast
          bcs   +
-         jsr   PreReadSector
-         tax
          pla
-         txa
+         jsr   PreReadSector
          pha                                    ; replace status (on stack) with new status returned from PreReadSector
 +        cmp   #kSectorIgnore                   ; skip this sector?
          beq   nextsector

src/strings/en.a

@@ -123,6 +123,7 @@ StringTable
          !word .rdos13
          !word .ssi
          !word .aacount
+         !word .infocom18
 ;
 ; Text can contain substitution strings, which
 ; are replaced by current values at runtime. Each
@@ -148,7 +149,7 @@ StringTable
 ; can be set directly before calling PrintByID.
 ;
 .header
-         !text "Passport by 4am               2018-10-14",$00
+         !text "Passport by 4am               2018-12-28",$00
 .mainmenu
          !text "________________________________________",$8D,$8D,$8D,$8D,$8D,$8D,$8D
          !text "              "
@@ -456,4 +457,6 @@ StringTable
          !text "T%t,S%0 Found SSI protection check",$8D,$00
 .aacount
          !text "T%t,S%0 Found AA nibble count",$8D,$00
+.infocom18
+         !text "T00,S00 Found Infocom 18-sector format",$8D,$00
 }

src/strings/enid.a

@@ -109,4 +109,5 @@ s_davidson =   $67
 s_rdos13   =   $68
 s_ssi      =   $69
 s_aacount =    $6A
-STRINGCOUNT =  $6B
+s_infocom18 =  $6B
+STRINGCOUNT =  $6C