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Version analysis of DELT

This code appears in the following versions (click to see it in the source code):

Code variations between these versions are shown below.

Name: DELT Type: Subroutine Category: Save and load Summary: Catalogue a disc, ask for a filename to delete, and delete the file
This routine asks for a disc drive number, and if it is a valid number (0-3) it displays a catalogue of the disc in that drive. It then asks for a filename to delete, updates the OS command at DELI so that when that command is run, it deletes the correct file, and then it does the deletion.
Other entry points: DELT-1 Contains an RTS
.DELT JSR CATS \ Call CATS to ask for a drive number (or a directory \ name on the Master Compact) and catalogue that disc \ or directory BCS SVE \ If the C flag is set then an invalid drive number was \ entered as part of the catalogue process, so jump to \ SVE to display the disc access menu

Code variation 1 of 6Specific to an individual platform

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LDA CTLI+1 \ The call to CATS above put the drive number into STA DELI+4 \ CTLI+1, so copy the drive number into DELI+4 so that \ the drive number in the "DE.:0.E.1234567" string \ gets updated (i.e. the number after the colon)
IF _SNG47 LDA CTLI+4 \ The call to CATS above put the drive number into STA DELI+8 \ CTLI+4, so copy the drive number into DELI+8 so that \ the drive number in the "DELETE :1.1234567" string \ gets updated (i.e. the number after the colon) ENDIF
LDA CTLI+1 \ The call to CATS above put the drive number into STA DELI+7 \ CTLI+1, so copy the drive number into DELI+7 so that \ the drive number in the "DELETE:0.E.1234567" string \ gets updated (i.e. the number after the colon)

Code variation 2 of 6Related to the Master version

When deleting a file via the disc menu, the disc and 6502SP versions ask for the "FILE TO DELETE?", while the Master version asks for the "COMMANDER'S NAME?".

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LDA #9 \ Print extended token 9 ("{clear bottom of screen}FILE JSR DETOK \ TO DELETE?")
LDA #8 \ Print extended token 8 ("{single cap}COMMANDER'S JSR DETOK \ NAME? ")
 JSR MT26               \ Call MT26 to fetch a line of text from the keyboard
                        \ to INWK+5, with the text length in Y

 TYA                    \ If no text was entered (Y = 0) then jump to SVE to
 BEQ SVE                \ display the disc access menu

Code variation 3 of 6A variation in the comments only

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\ We now copy the entered filename from INWK to DELI, so \ that it overwrites the filename part of the string, \ i.e. the "E.1234567" part of "DE.:0.E.1234567" LDX #9 \ Set up a counter in X to count from 9 to 1, so that we \ copy the string starting at INWK+4+1 (i.e. INWK+5) to \ DELI+5+1 (i.e. DELI+6 onwards, or "E.1234567")
IF _SNG47 \ We now copy the entered filename from INWK to DELI, so \ that it overwrites the filename part of the string, \ i.e. the "E.1234567" part of "DELETE :1.1234567" LDX #9 \ Set up a counter in X to count from 9 to 1, so that we \ copy the string starting at INWK+4+1 (i.e. INWK+5) to \ DELI+9+1 (i.e. DELI+10 onwards, or "1.1234567") \ \ Note that this is a bug - X should be set to 8, as a \ value of 9 overwrites the first character of the \ "SAVE" command in savosc \ \ This means that if you delete a file, it breaks the \ save command, so you can't save a commander file if \ you have previously deleted a file ELIF _COMPACT \ We now copy the entered filename from INWK to DELI, so \ that it overwrites the filename part of the string, \ i.e. the "1234567890" part of "DELETE 1234567890" LDX #8 \ Set up a counter in X to count from 8 to 0, so that we \ copy the string starting at INWK+5+0 (i.e. INWK+5) to \ DELI+7+0 (i.e. DELI+7 onwards, or "1234567890") ENDIF
\ We now copy the entered filename from INWK to DELI, so \ that it overwrites the filename part of the string, \ i.e. the "E.1234567" part of "DELETE:0.E.1234567" LDX #9 \ Set up a counter in X to count from 9 to 1, so that we \ copy the string starting at INWK+4+1 (i.e. INWK+5) to \ DELI+8+1 (i.e. DELI+9 onwards, or "E.1234567")
.DELL1

Code variation 4 of 6Specific to an individual platform

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LDA INWK+4,X \ Copy the X-th byte of INWK+4 to the X-th byte of STA DELI+5,X \ DELI+5 DEX \ Decrement the loop counter BNE DELL1 \ Loop back to DELL1 to copy the next character until we \ have copied the whole filename
IF _SNG47 LDA INWK+4,X \ Copy the X-th byte of INWK+4 to the X-th byte of STA DELI+9,X \ DELI+9 DEX \ Decrement the loop counter BNE DELL1 \ Loop back to DELL1 to copy the next character until we \ have copied the whole filename JSR getzp \ Call getzp to store the top part of zero page in the \ the buffer at &3000, as it gets corrupted by the MOS \ during disc access ELIF _COMPACT LDA INWK+5,X \ Copy the X-th byte of INWK+5 to the X-th byte of STA DELI+7,X \ DELI+7 DEX \ Decrement the loop counter BPL DELL1 \ Loop back to DELL1 to copy the next character until we \ have copied the whole filename JSR NMIRELEASE \ Release the NMI workspace (&00A0 to &00A7) so the MOS \ can use it, and store the top part of zero page in the \ the buffer at &3000, as it gets corrupted by the MOS \ during disc access ENDIF
LDA INWK+4,X \ Copy the X-th byte of INWK+4 to the X-th byte of STA DELI+8,X \ DELI+8 DEX \ Decrement the loop counter BNE DELL1 \ Loop back to DELL1 to copy the next character until we \ have copied the whole filename
 LDX #LO(DELI)          \ Set (Y X) to point to the OS command at DELI, which
 LDY #HI(DELI)          \ contains the DFS command for deleting this file

Code variation 5 of 6Specific to an individual platform

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JSR OSCLI \ Call OSCLI to execute the OS command at (Y X), which \ catalogues the disc
JSR SCLI2 \ Call SCLI2 to execute the OS command at (Y X), which \ deletes the file, setting the SVN flag while it's \ running to indicate disc access is in progress

Code variation 6 of 6Specific to an individual platform

This variation is blank in the Disc (docked) and 6502 Second Processor versions.

JSR getzp \ Call getzp to restore the top part of zero page from \ the buffer at &3000
 JMP SVE                \ Jump to SVE to display the disc access menu and return
                        \ from the subroutine using a tail call