; C02 Module filesys Assembly Language Eoutines for run6502 emulator
; This is the reference implementation of the filesys module 
; Requires external functions FSCMD and FSVDRV (fileio.h02)


        SUBROUTINE FILESYS

;remove(drv, &filnam) - Remove File filnam
;Args: A = Drive Identifier
;      Y,X = Address of Directory Name String
;Returns: A = Error Code (0 = None)
REMOVE: JSR FSVDRV        ;Validate Drive Number
        BCS .DRVERR       ;If Invalid Return Error
        LDA #'K'            ;Set Command to KILL (REMOVE)
.FSCMDX JSR FSCMD           ;Execute Command
        TXA                 ;Return Result
        RTS
        
;rename(drv, &filnam) - Rename File to filnam
;Setup: Call FSNAME with Address of Old Name
;Args: A = Drive Identifier
;      Y,X = Address of Directory Name String
;Returns: A = Error Code (0 = None)
RENAME: JSR FSVDRV        ;Validate Drive Number
        BCS .DRVERR       ;If Invalid Return Error
        LDA #'M'            ;Set Command to KILL (REMOVE)
        BNE .FSCMDX         ;Execute Command and Return Result

;inidrv(drv) - Initialize Disk Drive
;Args: A = Drive Identifier
;Returns: A = Error Code (0 = None)
INIDRV: LDA #$FF            ;Return Error - Not Implemented
        RTS

;chdrv() - Set Current Drive/Disk
;Args: A = Drive# | Disk#
;Returns: A = Result (0 - Success)
;         Y = Error Code (0 = None)
CHDRV:  JSR FSVDRV        ;Validate Drive Number
        BCS .DRVERR       ;If Invalid Return Error
        TAY               ;Set Drive Number
        SEC               ;Set Mode to Change
        BCS .GETDRV       ;Execute DRIVE Command and Return Result

;getdrv() - Get Current Drive/Disk
;Returns: A = Drive# | Disk# (0=Failure)
;         Y = Error Code (0 = None)
GETDRV: CLC               ;Set Mode to Get
.GETDRV LDA #'V'          ;Set Command to DRIVE
        BNE .FSCMDX       ;Execute and Return Result

;drvnam(drv) - Get Drive Name
;Args: A = Drive Number
;Returns: A = Drive Name (0=Failure)
;         Y = Error (0=None)
DRVNAM: JSR FSVDRV          ;Validate Drive Number
        BCS .DRVERR         ;If Valid
        LDY #0              ;  Set Error to None
        ADC #'@'            ;  Return Drive Letter
.DRVERR RTS