TRS-80 DOS - TRSDOS v1.3 - SYS06/SYS Disassembled

1. Program Overview

SYS6 is the TRSDOS 1.3 DOS Command Handler overlay for the TRS-80 Model III. It is a demand-loaded overlay residing in the SYSHI (high-system) PSECT, mapped to addresses 5200H–623DH. SYS6 is not resident in memory at all times; it is loaded by SYS0 whenever the user invokes any of the nineteen DOS commands it services.

On entry, Register C holds the order number of the requested command (matched against the TABCOM jump table), and Register Pair HL points to the remainder of the command line supplied by the user. SYS6 dispatches to the appropriate command handler via GETTAB/TABCOM, then returns control to the caller or to the DOS error handler as appropriate.

The nineteen commands handled by SYS6 are: APPEND, ATTRIB, AUTO, BUILD, CLEAR, CLOCK, CREATE, DATE, DIR, DO, DUMP, ERROR, FREE, LIB, LOAD, PAUSE, PROT, RENAME, and TIME. CLOCK, CLOCKN, and CLOCKF are forwarded to ROM routines; LIB lists available SYS1-resident library commands from the TABCOM table. LOAD uses the SYS0 program loader (LDPGM). The DO command installs a replacement keyboard DCB driver in high RAM to replay a .BLD script file as simulated keyboard input.

2. Memory Map

Address Range	Label	Description
5200H–623DH	SYS6 / SYSHI	Entire SYS6 overlay (assembled at ORG 5200H, END 5200H)
5200H	BEGIN	Entry point — command dispatcher
529BH	GETTAB	Table-search routine
52A8H	TABCOM	Command jump table (19 DCF entries + terminator)
52F6H (approx.)	AUTO	AUTO command handler
S6BUF3	S6BUF3	64-byte (40H) scratch buffer (DEFS 40H)
S6DCB1	S6DCB1	Primary file DCB (DEFS DCBSIZ)
S6DCB2	S6DCB2	Secondary file DCB (immediately follows S6DCB1)
S6BUF1	S6BUF1	256-byte sector buffer (ORG aligned to 256-byte boundary)
S6BUF2	S6BUF2	Second 256-byte sector buffer (S6BUF1 + 256)

3. Self-Modifying Code Variables and Workspace Locations

SYS6 makes heavy use of self-modifying code — immediate operand bytes within instructions serve as in-place storage for runtime values. These locations are internal to the overlay and are NOT recorded in the global RAM JSON. The table below documents all such locations identified from the source.

Label	Source Pattern	Description
AUTDRV	EQU $+1 / LD C,0	Drive number for AUTO command (self-modifying byte in LD C,n)
LPFLAG	EQU $+1 / LD BC,0	Line-printer flag for DIR and FREE output routing
S6DLFN	EQU $+1 / LD B,0	DIR command: current directory LFN counter
S6DDRV	EQU $+1 / LD C,0	DIR command: current drive number
PNTBUF	EQU $+1 / LD HL,0	DIR command: rolling pointer into hash-code buffer
SYS	EQU $+1 / LD DE,0	DIR command: user's "show SYS files" switch
S6INV	EQU $+1 / LD DE,0	DIR command: user's "show invisible files" switch
SAVMTH	EQU $+1 / LD A,0	DIR: creation month saved for display
SAVYR	EQU $+1 / LD A,0	DIR: creation year saved for display
LRL2	EQU $+1 / LD A,0	DIR: logical record length saved for record-count calculation
S6EOF	EQU $+1 / LD L,0	DIR: EOF byte saved for record-count calculation
DRV3	EQU $+1 / LD C,0	PROT command: drive number
INPPAS	EQU $+1 / LD DE,0	PROT command: pointer to entered old password hash
PW	EQU $+1 / LD DE,0	PROT command: new password hash (from SWITCH parse)
LOCK	EQU $+1 / LD DE,0	PROT command: lock password hash
PASSW	EQU $+1 / LD DE,0	PROT command: user-supplied hash to write to directory
BUFSAV	EQU $+1 / LD HL,0	PROT command: rolling pointer through directory buffer
STAT	EQU $+1 / LD D,0	ATTRIB command: attribute OR-mask to apply
STAT1	EQU $+1 / OR 0	ATTRIB command: protection-level value to OR in
ISTAT	EQU $+1 / OR 0	ATTRIB command: invisible-bit OR-mask
ISTAT1	EQU $+1 / AND 0FFH	ATTRIB command: invisible-bit AND-mask (for clearing)
RELO1 / START	EQU $+1 / LD HL,0	DUMP command: modified start address (self-modifying LD HL,nn)
RELO	EQU $+2 / LD IY,0	DUMP command: relocation base address (self-modifying LD IY,nn)
END	EQU $+1 / LD HL,0	DUMP command: ending address
TRA	EQU $+1 / LD HL,0	DUMP command: transfer address written to CMD file
TMPDCB	EQU $+1 / LD DE,0	DO command: temporary DCB pointer during setup
GODCB	EQU $+1 / LD DE,0	DO command: DCB pointer stored in the GOGO1 keyboard stub
LOWRAM	EQU $+1 / LD DE,0	CLEAR command: lower address of range to clear
HIGRAM	EQU $+1 / LD HL,0	CLEAR command: upper address of range to clear
NEWMEM	EQU $+1 / LD HL,0	CLEAR command: new MEMEND value if MEM option given
S6LRL	EQU $+1 / LD BC,0	CREATE command: parsed LRL value
NRECS	EQU $+1 / LD BC,0	CREATE command: parsed record count
HEXADD	(label on DEFM '0000')	CLEAR/DUMP: 4-byte ASCII hex address in "MEMORY FAULT AT X" message
DCOUNT	DEFB 0	DUMP command: residual byte count for partial sector
NAMFIL	DEFW 0 × 4 / DEFB 0	DUMP command: 9-byte filename scratch area
BIN	DEFB 0 / DEFW 0	DATE/TIME conversion: 3-byte binary result buffer
NAME1	DEFS 10H	RENAME command: 16-byte buffer for old filename
NAME2	DEFS 10H	RENAME command: 16-byte buffer for new filename
BUFPNT	DEFW 0	Miscellaneous buffer pointer (reserved word)
COUNT	DEFB 0	FREE command: current track counter
CDIRET	DEFB 0	FREE command: directory track number (from TRKGET)
DPRT1/DPRT2/DPRT3	DEFM '00'/'00'/'00~'	DATE/TIME display: three two-digit ASCII fields
DELIM1/DELIM2	DEFM ':'	DATE/TIME display: delimiter characters (patched to '/' for date)
GOSAVE	(referenced in DO)	DO command: saved original keyboard DCB driver address
DOFLAG	(referenced in DO/CLEAR/PAUSE)	DO active flag (FFH = active, 0 = inactive) — in external RAM

4. Major Routine List

Label	Description	Entry / Exit Conditions
BEGIN	Main entry point — command dispatcher. Saves command line pointer, clears FLAG1/SCAFLG/BASICG, calls GETTAB to look up command in TABCOM, then returns into the command via EX (SP),HL / RET.	Entry: C = command order number, HL → command line. Exit: falls through to command, or jumps to error handler.
BEGIN1	Continuation for "command not found" path — pops HL and falls into ERR2.	Entry: called from BEGIN on C flag set by GETTAB.
ERR1	FILE ALREADY EXISTS error (28H / EFAT).	Loads A = 28H, jumps to ERRX → ERR (SYS0).
ERR2	ILLEGAL PARAMETER error (0BH / ERICP).	Loads A = 0BH, jumps to ERRX.
ERR3	MISSING PARAMETER error (0AH / ERCPM).	Loads A = 0AH, jumps to ERRX.
ERR4	ACCESS DENIED error (19H / EFAD).	Loads A = 19H, jumps to ERRX.
ERR5	Displays "End less than Start" message.	HL → MES5, jumps to ERRY → PRINT.
ERR6	Displays "Start less than 6000~" message.	HL → MES6, jumps to ERRY.
ERR7	Displays "Memory fault at X nnnn" message.	HL → BADRAM, jumps to ERRY. Address filled in by HEXS into HEXADD.
ERR9	DISK DRIVE NOT IN SYSTEM error (02H / EDNS).	Loads A = 02H, jumps to ERRX.
ERR13	Displays "LRL of Files Do NOT Match~" message.	HL → BADLRL, jumps to ERRY.
ERRX	Common error jump to SYS0 ERR routine.	Entry: A = error code. JP ERR (SYS0 at 6132H).
ERRY	Common message print and return.	Entry: HL → message. JP PRINT (SYS0).
GETTAB	Searches TABCOM for a matching command order number. Each entry is a 3-byte DCF record: [order-byte][addr-low][addr-high]. Scans sequentially until match or 0 terminator.	Entry: C = order number, HL → TABCOM. Exit: NZ+NC with HL = command address on match; SCF (carry set) if not found.
TABCOM	Jump table — 19 DCF macro entries, each 3 bytes: command order code byte + 16-bit handler address. Terminated by DEFB 0.	Read-only data; searched by GETTAB.
AUTO	AUTO command — reads or writes the auto-start command in the disk GAT sector. Optionally accepts a drive specifier and a command name. Pads command to 32 bytes and writes via WRGAT.	Entry: HL → command line. Uses RDGAT/WRGAT (SYS0). Displays "Auto = <command>" or "Auto = ~" if cleared.
S6DATE	DATE command — displays current date or updates it. Parses MM/DD/YY via CONV1/DECBIN. Validates ranges. Stores into YEAR/DTSAVE (SYS0 RAM).	Entry: HL → command line, C = '/'. Exit: RET or JP ERR2.
S6TIME	TIME command — displays current time or updates it. Parses HH:MM:SS via CONV1/DECBIN. Validates ranges. Stores into SECOND (SYS0 RAM).	Entry: HL → command line, C = ':'. Exit: RET or JP ERR2.
CLOCK	CLOCK command — calls SYS1 CHKFLG to determine ON/OFF, then dispatches to ROM CLOCKF or CLOCKN.	Entry: HL → command line. Forwards to ROM clock routines.
CONV1	Decimal-to-binary conversion for 3-field values (date and time). Calls DECBIN twice per field, stores result into BIN+2 downward.	Entry: HL → ASCII string, C = delimiter, DE → BIN+2. Exit: Z on success, NZ on syntax error.
DECBIN	Converts two ASCII decimal digits at (HL) to a binary value.	Entry: HL → digit string. Exit: A = value (0–99), Z on success, NZ on error.
DECCHK	Reads one character from (HL), subtracts 30H. Returns NC if not a decimal digit.	Entry: HL → character. Exit: A = digit value; carry clear if not numeric.
LIB	LIB command — iterates through TABCOM and prints the first 6 characters of each command name, 8 per row.	Entry: none. Calls DSP (SYS0) for each character.
S6PROT	PROT command — changes the master disk password. Reads old password via MASINP/RDGAT, verifies it matches, prompts for new password, writes via WRGAT. Optionally locks all unprotected files.	Entry: HL → command line. Uses RDGAT, WRGAT, SREAD, XWRITE (SYS0).
MASINP	Reads up to 8 characters of keyboard input into BUFF1, then calls TRAP to compute the trap-door hash.	Exit: HL = computed hash code.
TRAP / SETTDC	Computes a two-byte trap-door hash code from an 8-character password string. Used for master password and file access/update passwords.	Entry: DE → password string, B = length. Exit: HL = hash. Returns NZ if hash would be zero (increments L).
RENAME	RENAME command — checks protection level (must be < write = level 3), moves names to DCBs, verifies old file exists and new name does not, updates directory record and hash table.	Entry: HL → command line. Calls GETSYN, OPEN, RDDIR, WRDIR, RDHIT, WRHIT, HASH, DSPNAM.
MOVNAM	Copies a filename from a DCB (DE) into a buffer (HL) until a control character is encountered, then appends a 03H terminator.	Entry: HL → dest, DE → DCB name field.
DSPNAM	Displays "oldname ---> newname CR" using PRINT (SYS0).	Uses NAME1, NAMARO, NAME2 data strings.
APPEND	APPEND command — opens two files, verifies their LRLs match, positions to EOF of the destination, copies all bytes from source to destination.	Entry: HL → command line. Calls GETSYN, SYNTAX, OPEN, OPENIT, POSEOF, GET, PUT, CLOSE.
DUMP	DUMP command — creates a CMD-format load file containing a memory range. Accepts START, END, TRA, RELO parameters. Writes load-format records (type 01) followed by an end record (type 02). Includes a remark record (type 05) with filename and date.	Entry: HL → command line. Uses SWITCH, GETSYN, INIT, CLOSE, PUTIT, PUT (SYS0).
PUTIT	Increments the DCOUNT residual count and writes one byte to disk via PUT (SYS0).	Entry: A = byte to write.
CREATE	CREATE command — initialises a new file with optional LRL and REC count parameters. Optionally pre-extends the file to the specified number of records.	Entry: HL → command line. Calls GETSYN, SWITCH, CONVHX, INIT, POSN, WRITE, CLOSE.
CONVHX	Converts a BCD value (from SWITCH parsing) to a 16-bit binary integer using a POWR10 lookup table.	Entry: HL = BCD value. Exit: HL = binary value.
CLEAR	CLEAR command — with no parameters, tests and clears RAM from S6DCB1 to MEMEND; with START/END parameters, clears a specified range; with MEM parameter, resets MEMEND. Detects and reports bad RAM via ERR7.	Entry: HL → command line. Calls SWITCH (SYS0), CLS (SYS0).
BUILD	BUILD command — creates a .BLD script file by accepting keyboard input line by line (up to 63 chars per line) until BREAK is pressed, then writes a terminating FFH byte and closes the file.	Entry: HL → command line. Uses GETSYN, PUTEXT, INITIT, KEYN (SYS0), PUT, CLOSE.
DO	DO command — sets up a .BLD file replay. Allocates high-RAM space, copies the GOGO1 keyboard stub there, redirects the keyboard DCB to it. Each subsequent keyboard read pulls one character from the DO file. Restores the original keyboard DCB on EOF.	Entry: HL → command line. Modifies KDCB+1 (SYS0 keyboard DCB), MEMEND, MEM1.
GOGO1–GOGO4	The DO keyboard stub — a small self-contained routine copied to high RAM. On each keyboard call it reads one byte from the DO file; on EOF it restores the original keyboard driver and clears DOFLAG.	Relocated to high RAM by DO. Calls GET (SYS0) via the relocated DCB pointer (GODCB).
SPAUSE	PAUSE command — prints "Press <ENTER> to continue~" then waits for ENTER. If the DO file is active it uses GETCR (keyboard matrix scan); otherwise it uses KEYN (SYS0).	Entry: HL → command line.
GETCR	Waits for the ENTER key by scanning memory location 3840H (keyboard matrix row).	Exit: Z set when ENTER detected.
EZZOR	ERROR command — converts a 1- or 2-digit decimal error number from the command line, ORs in 0C0H (detail bits), then falls into the ERR handler to display the corresponding error message.	Entry: HL → command line after 'ERROR '. Uses DECCHK.
PDATA	Outputs one character to the display via DSP (SYS0) or to the line printer via PRT (SYS0), depending on the LPFLAG self-modifying field.	Entry: A = character to output.
PRT2	Outputs a full message string via LPRINT (if LPFLAG set) and PRINT (SYS0).	Entry: HL → message string.
LPRINT	Prints a 03H-terminated string to the line printer via PRT (SYS0).	Entry: HL → string. Stops on 03H or after 0DH.
INKEY	Checks for BREAK (via BRKCHK / SYS0) then calls GETKBD. Supports hold-mode via HLDPAT.	Exit: A = character (NZ), or A=0 (Z) if no key pressed.
GETKBD	Keyboard scan — if DO is not active uses KBD (SYS0); if DO is active calls the keyboard DCB (KEYBDZ) via IX=KDCB.	Exit: A = character or 0.
HEXS	Converts one byte to two hex ASCII digits and stores them at (HL), advancing HL by 2. Used to fill HEXADD in the "MEMORY FAULT" message.	Entry: A = byte. Entry at HEXS1 for low nibble only.
HEXAAS	Converts a binary value to two decimal ASCII digits and stores them at (HL), advancing HL by 2. Used in date/time display.	Entry: A = value.
BINDEC	Outputs a 16-bit value as a right-justified decimal number preceded by two spaces. Calls ROM routines at 0A9AH / 1034H / 0FD9H and then prints digits from 4131H buffer.	Entry: HL = value. Calls PDATA for each character.
MSGPRT / MSGPR0	Formats date or time for display. Loads the delimiter into DELIM1/DELIM2 and fills DPRT1/DPRT2/DPRT3 with two-digit hex pairs from the date or time RAM variables, then calls PRINT.	Entry: C = delimiter ('/' for date, ':' for time). IX → HOUR or MONTH (SYS0 RAM).
REDIT / OPENIT / INITIT / GETSYN / GETDCB / GETDC1	Convenience wrappers that set up S6DCB1/S6BUF1 and call the SYS0 READ, OPEN, INIT, SYNTAX routines.	Standardised DCB/buffer setup for all file operations in this overlay.
DIR	DIR command — reads the GAT, HIT (hash index table), and directory records for a selected drive; displays filename, attributes, LRL, record count, granule count, extent count, EOF byte, and creation date for each visible file; then displays free-granule count.	Entry: HL → command line. Supports :n (drive), SYS, INV, PRT options via SWITCH. Calls RDGAT, RDHIT, RDDIR, BRKCHK, INKEY, BINDEC, PDATA, PRT2, CLS (all SYS0).
S6FREE	FREE command — reads the GAT for a selected drive and displays a graphical free-space map showing granule allocation status per track. Supports :n (drive) and PRT option.	Entry: HL → command line. Calls RDGAT, TRKGET, HEXCOV, PDATA, PRT2, CLS (SYS0).
HEXCOV	Converts a binary value to two decimal ASCII digits (BCD-style using repeated subtraction) and stores at (HL). Used to fill track numbers in the FREE map display.	Entry: A = value, HL → destination. Advances HL by 2.
SETTDC (alias TRAP)	Trap-door hash computation routine. Referenced in ATTRIB as SETTDC for file access/update password hashing.	Same routine as TRAP above.
LOAD	LOAD command — calls GETSYN to parse the filename, sets IY to SYS1IN (return address), pushes IY, and jumps to LDPGM (SYS0 program loader).	Entry: HL → command line. Returns to SYS1IN after program loads and runs.
ATTRIB	ATTRIB command — modifies protection attributes, visibility (I/N), access password, and update password of a file. Reads current directory record, patches attribute byte and password hash fields, writes directory back.	Entry: HL → command line. Calls GETSYN, OPEN, RDDIR, WRDIR. Uses SETTDC for password hashing.
LEGAL / LEAL	Character-class tests. LEGAL: accepts 0–9 and A–F (hex digits). LEAL: accepts 0–9 and A–Z (alphanumeric). Called by DUMP's filename-copy loop.	Entry: A = character. Exit: carry clear if character is in the accepted set.

5. Jump Table Mapping (TABCOM)

TABCOM is the command dispatch table searched by GETTAB. Each entry is produced by the DCF macro and consists of a 1-byte command order code followed by a 2-byte little-endian handler address (3 bytes total per entry). The table is terminated by a DEFB 0.

Order Code	Label	Command	Handler Label
01H (APP)	APP	APPEND	APPEND
02H (ATT)	ATT	ATTRIB	ATTRIB
03H (AUT)	AUT	AUTO	AUTO
05H (BULD)	BULD	BUILD	BUILD
06H (CLER)	CLER	CLEAR	CLEAR
07H (CLCK)	CLCK	CLOCK	CLOCK
0AH (CRET)	CRET	CREATE	CREATE
0BH (DTE)	DTE	DATE	S6DATE
0DH (DIRE)	DIRE	DIR	DIR
0EH (DODO)	DODO	DO	DO
10H (DMP)	DMP	DUMP	DUMP
11H (RERR)	RERR	ERROR	EZZOR
14H (FREEE)	FREEE	FREE	S6FREE
17H (LIBB)	LIBB	LIB	LIB
19H (LOADD)	LOADD	LOAD	LOAD
1CH (PAU)	PAU	PAUSE	SPAUSE
1DH (PROTT)	PROTT	PROT	S6PROT
20H (RENME)	RENME	RENAME	RENAME
24H (TTIME)	TTIME	TIME	S6TIME
00H	—	(end of table)	DEFB 0 terminator

6. Cross-References and Analysis Notes

ROM dependency: BINDEC calls three Model III ROM routines directly by address (0A9AH, 1034H, 0FD9H) and reads an ASCII result string from ROM address 4131H. These addresses are ROM-version specific and are not resolved through SYS0 vectors.

Keyboard matrix scan: GETCR reads address 3840H directly for the ENTER key row. This is a hardware-level dependency on the Model III keyboard matrix layout.

DO command high-RAM placement: The GOGO1–GOGO4 stub is copied to an address derived from MEMEND at runtime. The exact destination address is not fixed at assembly time; GODCB and GOSAVE within the stub are patched in place after the copy. The stub length is computed as GOGO4−GOGO1 in the source.

Self-modifying code note: Several locations (RELO1/START, END, TRA, RELO) use the EQU $+n pattern targeting the operand of multi-byte LD instructions. The disassembler mis-decodes some of these — most notably at the RELO/START/END cluster — rendering .BYTE 32H in place of LD (nnnn),A. The source is authoritative for byte counts and instruction boundaries in these regions.

LEAL vs. LEGAL: SYS6 defines two character-class predicates: LEGAL (hex digits 0–9, A–F) and LEAL (alphanumeric 0–9, A–Z). These are used in DUMP's filename copying loop. The near-identical names appear to be a deliberate abbreviation convention in the original source.

LIBCOM dependency: The LIB command iterates TABCOM treating each entry as a 3-byte record where the first 6 characters are the printable command name. However, the source label is LIBCOM, not TABCOM. Examination shows LIB starts at LIBCOM which in context resolves to the same table — the two labels may be aliases or LIBCOM may refer to a separate string-only table not present in the visible source. This warrants further investigation against the binary.

5213H - BEGIN1 - Continuation of the above initial processing routine. Jumped here if there was no routine match.

5218H - ERR3 - Process a PARAMETER NOT FOUND error.

521CH - ERR1 - Process a FILE ALREADY EXISTS error.

5220H - ERR5 - Display "END LESS THAN START" and RETurn.

5225H - ERR6 - Display "START LESS THAN 6000" and RETurn.

522AH - ERR7 - Display "MEMORY FAULT AT X 'nnnn'" and RETurn.

522FH - ERR13 - Display "LRL OF FILES DO NOT MATCH" and RETurn.

5234H - ERR9 - Process a DISK DRIVE NOT ON error.

5238H - ERR4 - Process a FILE ACCESS DENIED error.

523DH - ERRY - Display the message pointed to by Register Pair HL via the ROM and RETurn.

5240H - MES5 - Message Storage Area.

529BH - GETTAB - Routine to Parse the Table of Functions looking to match the requested function number (held in Register C on entry).

52AAH - FOUND - Continuation of the routine to Parse the Table of Functions. If we are here, then HL is pointing to the entry in the lookup table which matches the desired routine held in Register C on entry.

52B1H - NOTFND - Continuation of the routine to Parse the Table of Functions. If we are here, then we parsed the table of functions but did not fine one which matches the requested function number (held in Register C on entry).

52B3H - TABCOM - Table of Functions in this Overlay.

52EDH - AUTO Library Command - Function 3

5315H - AUTO4 - Continuation of the AUTO command; jumped here if there was a command character found in the passed command line. This routine will fill the command line to be 31 chararcters (with spaces) and put it into the appropriate location in the GAT sector.

5349H - AUTO7 - Continuation of the AUTO command; jumped here if we reached the end of the AUTO command as stored in the GAT sector.

5355H - AUTMSG - AUTO COMMAND MESSAGE STORAGE AREA.

5361H - S6DATE - DATE Library Command - Function 11

53ABH - S6TIME - TIME Library Command - Function 36

53E2H - CLOCK Library Command - Function 7. Exits with Z FLAG for OFF and NZ FLAG for ON.

53EBH - BIN - BYTE STORAGE AREA FOR TIME AND DATE ROUTINES.

53EEH - CONV1 - Subroutine within the DATE COMMAND to decode the date and validate for proper delimeters.

5403H - DECBIN - Subroutine within the DATE COMMAND to decode a two digit number pointed to by Register Pair HL; results in Register A.

5418H - RET1 - Subroutine within the DATE COMMAND to exit with the error status set.

541AH - DECCHK - Subroutine within the DATE COMMAND to convert a COMMAND LINE byte pair to decimal. Exits with NC FLAG set if there is an error.

5423H - LIB Library Command - Function 23

5450H - S6CR - Continuation of the LIBRARY COMMAND; jumped to if we have finished displaying the OVERLAY 1 COMMAND TABLE.

5455H - S6PROT - PROT Library Command - Function 29

The next few instructions put the password hash stored in Register Pair DE into the UPDATE and ACCESS password slots of the DIRECTORY SECTOR in RAM.

551AH - MASINP - SUBroutine as part of the PROT routine.

5526H - OLDMAS - MESSAGE STORAGE AREA for the PROT command.

554EH - SWTCH5 - PARAMETER STORAGE AREA for the PROT command.

555FH - TRAP - SUBROUTINE from the PROT library command to encode a password.

559FH - RENAME Library Command

The next 4 instructions just set DE = HL + 5, which is the the pointer to the FILENAME in the directory entry.

563DH - MOVNAM - Copy the contents of (DE) to (HL) until a control character is reached, at which point JUMP to 5647.

5647H - MOVNA1 - Continuation of the 563DH routine; add a 03H Terminator and RETurn.

564AH - DSPNAM - SUBROUTINE called from 5603H to Display a Verification Message of "filename1 ----> filename2".

5666H - NAME1 - MESSAGE STORAGE AREA for the RENAME Command.

568EH - "APPEND" Command.

56DAH - CONT - Continuation of APPEND Command. This routine is jumped to from 56CC if we got a DEVICE READY regarding FILESPEC 1 after reading a byte.

56EDH - CLOZE - Close FILESPEC 1 and FILESPEC 2 and RETurn.

5700H - "DUMP" Command.

5741H - SPCFIL - Part of the DUMP command. Jumped here if the character of the filename stored in Register A is INVALID.

57F4H - DOEND - Part of the "DUMP" COMMAND. Jumped here when there are no more bytes to save.

581CH - PUTIT - Part of the "DUMP" command. This routine is called each time a byte needs to be written, as it also includes that that byte in the running byte count.

5822H - CMD - MESSAGE and RAM STORAGE AREA for the DUMP COMMAND.

584FH - "LOAD" Command.

585EH - "ATTRIB" Command.

5893H - NEXTA - Continuation of the "ATTRIB" Command. Jumped here if a "(" was Found.

58C8H - CMP2 - Continuation of the "ATTRIB" Command. Jumped here during the LEVEL TABLE search when the first character of the desired level matches the first character in the level table; to check the rest for matches

58FAH - INVISB - Continuation of the "ATTRIB" Command. Jumped here if a "I" was found after a "(" was found.

590AH - NONINV - Continuation of the "ATTRIB" Command. Jumped here if a "N" was found after a "(" was found.

591AH - ACCESS - Continuation of the "ATTRIB" Command. Jumped here if a "A" was found after a "(" was found.

592FH - UPDATE - Continuation of the "ATTRIB" Command. Jumped here if a "U" was found after a "(" was found.

5944H - GETEND - Continuation of the "ATTRIB" Command. Jumped here to position to the next parameter on the command line.

594CH - GETEN1 - Continuation of the "ATTRIB" Command. Jumped here from the "position to next parameter" subroutine if a control character was detected.

596DH - DONEA - Continuation of the "ATTRIB" Command. This will mask the values and set the passwords and put them in the RAM STORAGE LOCATION for the DIRECTORY ENTRY.

59AFH - INDEX - MESSAGE AND RAM STORAGE AREA for the "ATTRIB" Command.

59BDH - LEGAL - Part of the "DUMP" Command. Tests the validity of a HEXIDECIMAL NUMBER stored in Register A.

59CBH - LEAL - Part of the "DUMP" Command. Tests the validity of an ALPHA NUMERIC character stored in Register A.

59D9H - "DIR" command.

5AAEH - NOSYS - Continuation of the "DIR" Command. Jumped here when we have passed the first filtering hurdles and the directory entry being pointed to has still not yet been disqualified from being displayed.

5ABAH - NOTINV - Continuation of the "DIR" Command. Display the filespec, 1 space, and the extension.

5AF6H - ENDEXT - Continuation of the "DIR" Command. Position the Cursor to the Right Location.

5B07H - Continuation of the "DIR" Command. Display NON-INV, INV, or SYS FILE

5B23H - Continuation of the "DIR" Command. Display the PROTECTION (U)PDATE, A(CCESS), or B(OTH) UPDATE AND ACCESS

5B4FH - Continuation of the "DIR" Command. Display the PROTECTION NUMBER OF THE PROTECTION LEVEL.

5B58H - Continuation of the "DIR" Command. Get the EOF Byte.

5B5FH - Continuation of the "DIR" Command. Get the LRL Byte.

5B70H - Continuation of the "DIR" Command. Calculate the number of records in a file.

5B87H - NLR256 - Continuation of the "DIR" Library Command. Jumped here from 5B7CH if the LRL is not zero so that we can calculate the number of LRL for records other than a 256 LRL.

5BB6H - CONT4 - Continuation of the "DIR" Command. Display the Number of GRANS in a File.

5BBCH - Continuation of the "DIR" Command. Display the Number of EXTENTS in a File.

5BC2H - Continuation of the "DIR" Command. Display the EOF BYTE OFFSET of a File.

5BCBH - Continuation of the "DIR" Command. Display the DATE OF CREATION for a File.

5BE1H - NO - Continuation of the "DIR" Command. Check for a User HOLD Key.

5BE7H - NXTFIL - Continuation of the "DIR" Command. Bump to the next file in the directory.

5BF5H - ENDFIL - Continuation of the "DIR" Command. All Files have been displayed. Calculate the number of FREE GRANS on the Disk.

5C32H - TITL2 - MESSAGE AND STORAGE for the "DIR" Command.

5CC3H - SWTCH3 - "DIR" Command Parameter Table.

5CDCH - S6FREE - "FREE" Library Command.

5D8EH - L6PO9 - Continuation of the "FREE" command. Jumped here if the track is NOT flawed (so as to skip the display of a flawed track).

5D9AH - L6PO10 - Continuation of the "FREE" command. Jumped here if the track is NOT flawed (so as to skip the display of a flawed track) and we have not yet hit the directory track.

5DA6H - SETX - Continuation of the "FREE" command. Jumped here if the track is NOT flawed (so as to skip the display of a flawed track) and we have not yet hit the directory track AND the gran is allocated.

5DC2H - TITLE - MESSAGE and BYTE STORAGE AREA for "FREE".

5E46H - HEXCOV - Subroutine in the "FREE" Library Command to Generate a 2-Digit Decimal Number.

5E52H - "CREATE" Library Command.

5EB1H - SWTCH2 - PARAMETER TABLE for the "CREATE" Command.

5EC2H - CONVHX - SUBROUTINE in the "CREATE" Command to Convert the Binary Coded Decimal Value Pointed to by Register Pair HL into Binary.

5ED6H - ADDHL - SUBROUTINE to the above SUBROUTINE in the "CREATE" Command. Converts the value held in A to Hexadecimal.

5EF7H - POWR10 - POWERS OF 10 TABLE for the "CREATE" Command.

5EFFH - "CLEAR" Library Command.

5F1FH - CLEARX - Subroutine in the "CLEAR" Library Command. Jumped to if we have parameters on the command line.

5F4BH - CHKMEM - Continuation of CLEAR command

5F63H - CLEAR0 - Part of the "CLEAR" Library Command. Jumped here if the user didn't provide any parameters.

5F91H - CLRTAB - PARAMETER TABLE for the "CLEAR" Command.

5FC9H - "BUILD" Library Command.

6001H - BLDEXT - Continuation of the "BUILD" Library Command; jumped to if a BREAK key was hit.

600FH - S6PRMP - MESSAGE and BYTE STORAGE AREA for "BUILD".

603DH - "DO" Library Command.

60A6H - GOGO1 - "DO" Driver Routine.

60B8H - OKGO - Continuation of the "DO" Command. Jumped here if there was an error in getting characters.

60BEH - GOGO3 - JUMP to 60BEH to terminate the "DO" Execution.

60CCH - EXT5 - MESSAGE STORAGE AREA for "DO".

60CFH - SPAUSE - "PAUSE" Library Command.

60EAH - SPAUS1 - Continuation of the "PAUSE" Library Command, Jumped here if the "DO" command is active.

60EFH - GETCR - Continuation of the "PAUSE" Library Command. Subroutine to read the keyboard for an ENTER key.

60F8H - PRESNY - MESSAGE STORAGE AREA for "PAUSE".

6114H - EZZOR - "ERROR" Library Command.

6135H - PDATA - Common Subroutine - Display or Print the Character held in Register A.

6147H - PRT2 - Common Subroutine - Display or Print the message pointed to by Register Pair HL.

6157H - LPRINT - Common Subroutine - Print a Message Pointed to by Register Pair HL, until a 03H or 0DH is reached.

6167H - INKEY - SUBROUTINE in the "DIR" Library Routine to Start Processing a @ (aka Pause) request.

617CH - HLDPAT - Continuation of the SUBROUTINE in the "DIR" Library Routine to Process a @ (aka Pause) keypress.

6188H - GETKBD - Continuation of the SUBROUTINE in the "DIR" Library Routine to Process a @ (aka Pause) keypress. This part scans the keyboard, bypassing the DO command.

61A1H - HEXS - Part of the "CLEAR" Library Command. Jumped here to insert a value into a message.

61B5H - HEXAAS - Part of the "DIR" Library Command to convert a value held in Register A (which is either FILE CREATION MONTH or FILE CREATION YEAR as extracted from a files directory entry) and place it in the middle of the message " 00/00", in the specific the location pointed to by Register Pair HL. Routine is called once with MONTH and then once with YEAR.

61C1H - BINDEC - Part of the "DIR" Library Command to display the contents of Register Pair HL in decimal form.

61E1H - DPRT1 - Message Storage Area for TIME and DATE DISPLAY.

61EAH - MSGPRT - Display TIME$ and DATE$. This routine is called by both the DATE and TIME library commands, and Register C holds the delimter character of either / or :.

61F0H - MSGPR0 - Part of the "DATE" and "TIME" Library Commands. This generates the text line of xx/xx/xx or yy:yy:yy.

6218H - REDIT - Routine to READ A RECORD from FILE 1.

6225H - OPENIT - Routine to OPEN from FILE 1.

622BH - GETDCB - Routine to Set the Variables Needed for a JUMP to 4424H.

6234H - INITIT - Routine to CREATE FILE 1.

623AH - GETSYN - Routine to CHECK FILE 1.